Date   

Re: [OT] Best glue to repair lifted trace?

 

I use Circuit Works CW2500 epoxy to repair traces on a PCB and overcoat the result.  Its a good epoxy but somewhat expensive.  All epoxy "glues" will melt when soldering so plan accordingly.  In your case I would 1.  remove the connector, 2.  use CW2500 to put the trace back on the board, 3.  scrape mask off a strip of the conductor after its repaired, 4.  solder a small wire or strip of copper tape to the repaired trace, 5. Put the connector (better, a new one) back on the board, 6. use CW2500 to overcoat the repaired trace.
Amazon and Newark sell CW2500 but I have no idea what the shipping might be to Austria.

On Saturday, May 4, 2019, 02:06:46 PM CDT, cheater cheater <cheater00@gmail.com> wrote:

Good warning. Thanks.

On Sat, May 4, 2019 at 6:20 PM Mark Goldberg <marklgoldberg@gmail.com> wrote:

Silicone will rip with mechanical stress. Epoxy is much stronger.

Regards,

Mark
W7MLG

On Sat, May 4, 2019 at 8:56 AM Brad Thompson <brad.thompsonaa1ip@gmail.com>
wrote:



cheater cheater wrote on 5/4/2019 10:15 AM:

That's the plan, unfortunately I can't find an acceptable source of
high temperature resistant, electrically insulating epoxy in Austria.
The closest is in Germany, but that's still 10 euro shipping.

On Sat, May 4, 2019 at 2:54 PM Tony Fleming <czecht@gmail.com> wrote:
<snip>
Hello--

Do you have automobile-supply stores in Austria such as this one...

https://www.autozone.com/
<https://www.vipauto.com/>
If so, you might investigate whether they sell high-temperature silicone
gasket sealant such as...


https://www.autozone.com/sealants-glues-adhesives-and-tape/rtv-adhesive/permatex-5-oz-14-g-ultra-black-hi-temp-rtv-silicone-gasket-maker/415412_0_0

This might do the job.

73--

Brad  AA1IP





Re: [OT] Best glue to repair lifted trace?

 

Good warning. Thanks.

On Sat, May 4, 2019 at 6:20 PM Mark Goldberg <marklgoldberg@gmail.com> wrote:

Silicone will rip with mechanical stress. Epoxy is much stronger.

Regards,

Mark
W7MLG

On Sat, May 4, 2019 at 8:56 AM Brad Thompson <brad.thompsonaa1ip@gmail.com>
wrote:



cheater cheater wrote on 5/4/2019 10:15 AM:

That's the plan, unfortunately I can't find an acceptable source of
high temperature resistant, electrically insulating epoxy in Austria.
The closest is in Germany, but that's still 10 euro shipping.

On Sat, May 4, 2019 at 2:54 PM Tony Fleming <czecht@gmail.com> wrote:
<snip>
Hello--

Do you have automobile-supply stores in Austria such as this one...

https://www.autozone.com/
<https://www.vipauto.com/>
If so, you might investigate whether they sell high-temperature silicone
gasket sealant such as...


https://www.autozone.com/sealants-glues-adhesives-and-tape/rtv-adhesive/permatex-5-oz-14-g-ultra-black-hi-temp-rtv-silicone-gasket-maker/415412_0_0

This might do the job.

73--

Brad AA1IP





Re: Again a 7854 power supply beast to be repaired...

unclebanjoman
 

OK Harvey,

I did as you suggested, putting a V and H plugin. Here the results:

1) Trace is moveable in both horizontal and vertical position. So I put the trace off-screen to avoid CRT damage.
2) Readout is visible.
3) All the display is highly blurred
4) Focus and astigmatism works but in a barely manner because the the display is at very very high intensity.
5) With another scope I checked the output of the Z-axys board (board A21, diagram 13) test point TP183: the output is stuck at approx. +120V. No pulses or other artifacts are visible. Moving the A, B or readout intensity has no effect.

Max

Max


Re: Again a 7854 power supply beast to be repaired...

Harvey White
 

On Sat, 04 May 2019 09:22:37 -0700, you wrote:

O.K. I checked power rails and found a short on -15V, pin 7 of P82 connector (sense).
NOTE: some other people was attempted to repair this poor 7854, so...they left behind a disaster with no success.

After careful inspection I found the P132 connector on the motherboard mounted wrong, shifted one pin left!
I pulled out P132 connector and reinsert it in the correct way, carefully matching all the pins.

Power up and... woah! It started! All the lights up!

BUT: now the bad surprise.
On the CRT I see a BIG unfocused and very, very brilliant spot centered on the screen (no plug-ins are inserted). The INTENSITY control has no effect (fully counterclockwise).
To avoid damage to the crt I turned it off immediately.
I turned the scope back on, just to perform a quick check on the low voltage regulator board A22: all voltages are perfect, all in range.
Check to see if the astigmatism control works, if focus works (do not
focus down to a full intensity spot).

Do this with at least a V and H plugin. That's a sanity check on the
V and H frame amplifiers. You ought to see readouts, too. Spot
should be moveable with the V and H controls, so you can move it off
the screen while you check the power supply voltages (just because it
comes up doesn't mean that there isn't still a bad cap somewhere).

The good news is that you have high voltage on the scope.

The question is if it's right, and the control voltages to the CRT are
ok.

That's what I'd do to start with.

Harvey



And now? Z board damaged? :-(
Where to check?

Max

.



Re: Again a 7854 power supply beast to be repaired...

Craig Sawyers <c.sawyers@...>
 

Oh dear - the dreaded one pin out problem. We've all done that at some point. I've got away with it
until I did it on my 577 curve tracer and took out most of the silicon. Fixing it is a "work in
progress".

Hopefully there won't be too horrendous damage.

Craog

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of unclebanjoman
Sent: 04 May 2019 17:23
To: TekScopes@groups.io
Subject: Re: [TekScopes] Again a 7854 power supply beast to be repaired...

O.K. I checked power rails and found a short on -15V, pin 7 of P82 connector (sense).
NOTE: some other people was attempted to repair this poor 7854, so...they left behind a disaster
with
no success.

After careful inspection I found the P132 connector on the motherboard mounted wrong, shifted one
pin left!
I pulled out P132 connector and reinsert it in the correct way, carefully matching all the pins.

Power up and... woah! It started! All the lights up!

BUT: now the bad surprise.
On the CRT I see a BIG unfocused and very, very brilliant spot centered on the screen (no plug-ins
are
inserted). The INTENSITY control has no effect (fully counterclockwise).
To avoid damage to the crt I turned it off immediately.
I turned the scope back on, just to perform a quick check on the low voltage regulator board A22:
all
voltages are perfect, all in range.

And now? Z board damaged? :-(
Where to check?

Max

.


Re: Again a 7854 power supply beast to be repaired...

unclebanjoman
 

O.K. I checked power rails and found a short on -15V, pin 7 of P82 connector (sense).
NOTE: some other people was attempted to repair this poor 7854, so...they left behind a disaster with no success.

After careful inspection I found the P132 connector on the motherboard mounted wrong, shifted one pin left!
I pulled out P132 connector and reinsert it in the correct way, carefully matching all the pins.

Power up and... woah! It started! All the lights up!

BUT: now the bad surprise.
On the CRT I see a BIG unfocused and very, very brilliant spot centered on the screen (no plug-ins are inserted). The INTENSITY control has no effect (fully counterclockwise).
To avoid damage to the crt I turned it off immediately.
I turned the scope back on, just to perform a quick check on the low voltage regulator board A22: all voltages are perfect, all in range.

And now? Z board damaged? :-(
Where to check?

Max

.


Re: [OT] Best glue to repair lifted trace?

Mark Goldberg
 

Silicone will rip with mechanical stress. Epoxy is much stronger.

Regards,

Mark
W7MLG

On Sat, May 4, 2019 at 8:56 AM Brad Thompson <brad.thompsonaa1ip@gmail.com>
wrote:



cheater cheater wrote on 5/4/2019 10:15 AM:

That's the plan, unfortunately I can't find an acceptable source of
high temperature resistant, electrically insulating epoxy in Austria.
The closest is in Germany, but that's still 10 euro shipping.

On Sat, May 4, 2019 at 2:54 PM Tony Fleming <czecht@gmail.com> wrote:
<snip>
Hello--

Do you have automobile-supply stores in Austria such as this one...

https://www.autozone.com/
<https://www.vipauto.com/>
If so, you might investigate whether they sell high-temperature silicone
gasket sealant such as...


https://www.autozone.com/sealants-glues-adhesives-and-tape/rtv-adhesive/permatex-5-oz-14-g-ultra-black-hi-temp-rtv-silicone-gasket-maker/415412_0_0

This might do the job.

73--

Brad AA1IP




Re: [OT] Best glue to repair lifted trace?

Brad Thompson
 

cheater cheater wrote on 5/4/2019 10:15 AM:

That's the plan, unfortunately I can't find an acceptable source of
high temperature resistant, electrically insulating epoxy in Austria.
The closest is in Germany, but that's still 10 euro shipping.

On Sat, May 4, 2019 at 2:54 PM Tony Fleming <czecht@gmail.com> wrote:
<snip>
Hello--

Do you have automobile-supply stores in Austria such as this one...

https://www.autozone.com/
<https://www.vipauto.com/>
If so, you might investigate whether they sell high-temperature silicone gasket sealant such as...

https://www.autozone.com/sealants-glues-adhesives-and-tape/rtv-adhesive/permatex-5-oz-14-g-ultra-black-hi-temp-rtv-silicone-gasket-maker/415412_0_0

This might do the job.

73--

Brad  AA1IP


Re: [OT] Best glue to repair lifted trace?

Adrian Nicol
 

I really don't understand this insistence on 'high temperature' epoxy, as I said, re-seat the connector and if it has no retention itself then clamp it or put a bit of epoxy away from the solder area to hold it , then solder, then epoxy.

On 5/4/2019 3:15 PM, cheater cheater wrote:
That's the plan, unfortunately I can't find an acceptable source of
high temperature resistant, electrically insulating epoxy in Austria.
The closest is in Germany, but that's still 10 euro shipping.


Re: Calibration and full checkout needed - Tek 7000 series

Harvey White
 

On Sat, 04 May 2019 09:44:43 -0400, you wrote:

John and Harvey, this really great information I wish I had BEFORE I got
started acquiring stuff (though all is not lost). To be clear, in terms of
acquiring additional scopes or plug-ins, today I already own 2 7603s, a
7603R, a 7633, a 466 (to Harvey's points about the 46x family), a 547(1A4),
and a T935. My vertical 7000 plug-ins are a mixture of 7A18's (which get me
to 4 channels on a 7000) and 7A15's (the military version). For horizontal,
it sounds like a 7A22 and 7A26 would be good to throw on the mix. For the
vertical, I have 7B53A's.
With the 76xx series you do need a dual timebase plugin, since there
are only 3 slots.

You're mixing up the letters. For 7000 series, the nomenclature goes
as follows (not all inclusive) and there's an exception.

7/letter/two numbers/optional letter N

7 for 7000 series
A for vertical plugins
B for horizontal plugins
CT (the exception) for the curve tracer (7CT1N)
D for digital
L for spectrum analyzers
S for sampling
T for timebase for samplers (7T11)

the N suffix indicates that readout circuitry was deleted from the
plugin.


I'm curious about your thoughts on the 75Mhz 7A15. Its sensitivity isn't
the 10uV of the 7A22, but with its 10x switch, it can apparently go down to
500uV.
Bandwidth limiting can be useful. The 7A22 is also differential,
which gives additional capability. If you want full bandwidth 75 Mhz,
then the 7A15 is useful,

Also, why would a 200Mhz 7A26 make sense in a 100Mhz 7603 (if it does)?
Because you get the scope frame limiting the bandwidth, not the
plugin. You should get the full 100 Mhz frame bandwidth. The further
advantage is that if you ever go to a faster mainframe, you don't need
to buy plugins for it (or not as many).


I love the Hantek idea.

For DMMs, I have a Fluke 87V and Agilent u1253b already. So I have no
immediate needs there.

Ultimately, I want to thin and enhance (ie: plug-ins) my herd down to only
that which is necessary (and good enough calibrated) for my applications
(again tube amps and radios). At 100Mhz without the flexibility of the
plug-ins, my feeling is the 466 is out (also because I don't need storage
which is also why the 7633 goes too, vs one of the 7603's).
I'd recommend keeping at least one storage scope. See the thread
about the 7854 power supply.

The advantage of the 466 is that it's more portable than any 7000
frame, or, shall we say, it was designed for it.

If you want the versatility of the 7000 series and the storage
capability, I'd keep the 7633.

The third rule of acquisition states that it's easier to keep
something than to try to find one again.

You'll find that having spares, say you have a lot of 7A26, and still
have some 7A18, well, the 7A18 can be be the "if something else
breaks....." plugin.

Since it takes a scope to fix a scope (very frequently), I'd not be
without a spare. I can see situations where, if working on two
things, you'd like a separate scope rather than have to tear down and
rebuild a setup.

I generally work in two or three locations, two of the locations have
scopes, all have power supplies, two have meters. One is the full
lab.

I'm working on microprocessor based, FPGA enhanced, sensor and
graphics platforms, so the power supplies are needed, scopes may be,
meters can be, etc....



I haven't played with the 35Mhz T935 yet but really see no need for it.
Portability is not an issue for me.
Might be a nice gift to a maker group, but not the ones that charge
high admissions fees... (those IMHO are strictly profit centers, and
are more interested in making money than providing facilities...).

If you can find someone who is really working on electronics in high
school or college, that could help as well...


Technically, the 50Mhz 547 seems unjustifiable to keep. Although the
TekWiki mentions a cascading option that, if I read it correctly, gets its
sensitivity down to 200uV of sensitivity (not as good as the 7A22 for low
freq, but better than the 7A15). But I haven't read into it yet. Maybe I
have it wrong. In the end, I just may keep the 547 for its sheer beauty.
Can't think of a thing wrong with that. Some people adore the old
tube scopes, and if you have one that works, they're pretty rare. They
get bought at high prices and robbed for the tubes.

Had you considered making a small "history of oscilloscopes" exhibit?




Finally, the big question (bringing it back to the thread) for me is how
badly do I need the stupid money TM500-related calibration gear or is there
a short cut with something else that gets me close enough for my
application now that I have the signal standardized plug in.
This restricts you to the 7000 series for right now, but yes, there
are ways.

Note that the signal standardizer substitutes for a constant amplitude
signal generator for the frame, but not for any plugin. Pay attention
to the minimum frequency limit on the standardizer, they mean it.

You are going to get close.

As pointed out, any DMM is better (more accurate) than a scope. So
you could use a decent DMM as a DC voltage "standard" to at least look
at voltages on the scope. While you'd like the 1-2-5 sequence that
the PG506 provides, if you can find a decade divider, that would allow
you to relatively easily dial in known voltages (from a known voltage)
to check most of the ranges on a plugin. You could also simply make a
series of voltage dividers with 1% resistors that would give you a
convenient sequence.

You're pretty much calibrating the scopes to the DMM, not elegant, but
should be good for performance verification. You'd want a decent
signal source, DC and AC, though.

Timing? Assuming you're happy with working in digital, buy a packaged
oscillator, 5 volts is fine, 50 Mhz is ok. Divide by 10 with decade
counters, use 7490's (which are /5 /2) wire them as /5 first, then
/2. not that it's super important, but it makes the /10 composite
output symmetric.

What you're looking for is to divide by 10, then take that div10
output and tap off a div2 and div 5 for each. Doing that, you could
also use 74LS192 decade counters, and that gives you the requisite
1,2,5 timing for most scopes.

That handles horizontal timebase stuff.

So yes, you can make stuff if you want. These won't be as nice (or as
full featured) as the stuff made for the scope calibration, but
they'll easily do performance verification.

If you had a synthesized signal generator, it would substitute for the
TTL stuff. All depends on what you have and are willing to make.


Harvey



As always, thank you for your feedback.


On May 3, 2019 9:48:48 PM "John Kolb" <jlkolb@jlkolb.cts.com> wrote:

If you go with the 7000 series mainframe, I'd recommend the 7A26 and
7A22 plugins as primary. The 7A26 for frequencies above 1 MHz, and the
7A22 for low amplitude. the 7A22 has sensitivity down to 10uV/div, and
switch selectable high pass and low pass filters for various freqs.
It's been invaluable to me working with low level audio in a system with
lots of high freq digital noise all over.

The 7A13 is great for measuring AC signals accurately or for high freq
signals down to 1 mV/div but for audio work, you are generally
interested in knowing a voltage within 0.1 db than 0.1% voltage accuracy.

I take the vertical output from the 7000 mainframe into a Hantek digital
scope to freeze a signal trace and store to a USB thumb drive for
transfer to a computer for documentation. In my application, the Hantek
picks up so much digital noise to be worthless viewing even high level
signals without filtering through the 7A22 first.

I'd recommend an AN873 DMM, Digital Multimeter. $30 on Amazon, and
specs as good as the Fluke 77-V, $372. The two I have were both within
the 0.05% spec at 10V and 1V DC. As well as AC and DC volts and current
and ohms, it also measures frequency, capacitance, and temperature. The
AC voltage measurement is true RMS, but dies rapidly above 2 kHz.
Plenty good enough to measure AC or DC volts applied to a scope input to
verify scope basic accuracy.

John

On 5/3/2019 7:39 AM, Harvey White wrote:
On Thu, 2 May 2019 19:59:08 -0400, you wrote:

Harvey, to your point about the application, to be clear, my applications
in order of priority are:


1. tube amp repair.. basically an audio application involving low
frequencies. I occasionally end up in solid state land but have had luck
isolating a misbehaving component with old time techniques.
2. vintage radio repair


So, very basic stuff where the exacting accuracy of the oscilloscope may
not be necessary. But I'd like for them to be the ballpark.
Ballpark you can get without special equipment. DMM calibration is
something else, but there are 10 volt very accurate references
available. It's when you star looking at 4 1/2 digits and up where
things start to get tricky with the reference. That's also just DC
volts, AC, ohms, and current are separate matters.

For what you're looking at, you would like to have a 100 Mhz scope, at
least dual channels. If you're doing audio and you want to start
poking around audio preamps, you'd want a fairly sensitive scope to
match the expected signal levels.

5 mv/div may be too little.

For portable scopes, the 465 would do well. If you want digital as an
add-on (either, without forcing you into digital at all times), then a
468 would work well.

IF you want a 7000 series scope, then a 7603 would do well, 7B53
plugin for sweep, 7A26 (two of them) gives you 4 channels, a pair of
7A18's would give you 75 Mhz bandwidth, which would be good enough,
although I'd go for the 7A26 if you get another scope frame.

You might want to look at the 7A13 (I prefer the electronic readout
one), and the 7A22. Both are differential, have some good low ends for
input ranges, and may be more of what you want for debugging preamps.

almost any 10x probe with a 1meg input match on the plugin would work.

If you care to, the 7704 is a 200 Mhz bandwidth scope, and would work
well with the same plugins.

For specialized test equipment, the SG502 is an ultra low distortion
signal generator module, and the AA501 or AA5001 is a distortion
analyzer. Bear in mind that audio enthusiasts have bid up the prices
on these, because price is no object.

Nice to have, though.

a good 4 1/2 digit meter would help, you'd like the full range of AC,
DC, AC current (could be useful) and DC current.

Harvey



On Thu, May 2, 2019 at 7:27 PM Tony Fleming <czecht@gmail.com> wrote:

Sorry for asking this question: What is " levelling head kit" ?
I think it has something to do with calibration....

On Thu, May 2, 2019 at 5:25 PM Craig Sawyers <
c.sawyers@tech-enterprise.com>
wrote:

And you can get a levelling head kit (no housing) for the SG504 from me
...


David
I have one of your kits and have had for quite a while. Just waiting to
find an SG504 without head
that is less than stupid money ;-)

Craig





Re: Again a 7854 power supply beast to be repaired...

Harvey White
 

On Sat, 04 May 2019 07:22:34 -0700, you wrote:

Good news!
I found another couple of leaky electrolytic. So I decide to change ALL electrolytic capcitors on inverter and control/rectifier board, using Nichicon PWM-R 105 deg (low ESR).
Replaced the two big capacitors 950uF 200V (one of these was severely leaky) with new Nippon Chemi-Con 100uF 200V.
I built a decent dummy lod using the Dennis Tillman's scheme.

Finally the SMPS started up! All voltages was O.K.! Start-up is practically instantaneous and the the waveforms are in good agreement with those reported in the service manual.

Now the bad news.....
I reconnected the SMPS to the mainframe and... nothing happens. No lights, no trace, nothing.
I hear a regular tick tick (it was irregular and random before the cure). So I'm sure that the SMPS is correctly functioning but the service manual does not explain much about how to proceed in this case.

Any idea/suggestion?
Overload. You had bad caps on the power supply, you likely have bad
caps in the scope.

1) remove as many connections to the PS as possible. Check resistance
from the power lines to ground.

2) if you can isolate to a section, check that one out, of course. Do
all of this without plugins.

3) you can try plugging in each section to see if it holds down the
supply.

4) another scope can be used on the rails to see if the power supply
rail comes up or stays flat.

5) digital scope is by far the best for this, if you have one.

Divide and conquer works here. Check individual boards (with power
disconnected) for ESR and resistance on electrolytics from power to
ground. Be especially suspicious of the little gum-drop tantalums. If
they have a substantial series resistor (100 ohms or better, they
really won't hold down the supply unless it's a significant voltage).

Harvey



Max




Re: Again a 7854 power supply beast to be repaired...

george edmonds
 

Hi
A regular ticking means that you have a short on one of the power rails in the mainframe.
George G6HIG

On Saturday, May 4, 2019 3:25 PM, unclebanjoman <mmazza@inrete.it> wrote:


Good news!
I found another couple of leaky electrolytic. So I decide to change ALL electrolytic capcitors on inverter and control/rectifier board, using Nichicon PWM-R 105 deg (low ESR).
Replaced the two big capacitors 950uF 200V (one of these was severely leaky) with new Nippon Chemi-Con 1000 uF 200V.
I built a decent dummy lod using the Dennis Tillman's scheme.

Finally the SMPS started up! All voltages was O.K.! Start-up is practically instantaneous and the the waveforms are in good agreement with those reported in the service manual.

Now the bad news.....
I reconnected the SMPS to the mainframe and... nothing happens. No lights, no trace, nothing.
I hear a regular tick tick (it was irregular and random before the cure). So I'm sure that the SMPS is correctly functioning but the service manual does not explain much about how to proceed in this case.

Any idea/suggestion?

Max


Re: Again a 7854 power supply beast to be repaired...

unclebanjoman
 

Good news!
I found another couple of leaky electrolytic. So I decide to change ALL electrolytic capcitors on inverter and control/rectifier board, using Nichicon PWM-R 105 deg (low ESR).
Replaced the two big capacitors 950uF 200V (one of these was severely leaky) with new Nippon Chemi-Con 1000 uF 200V.
I built a decent dummy lod using the Dennis Tillman's scheme.

Finally the SMPS started up! All voltages was O.K.! Start-up is practically instantaneous and the the waveforms are in good agreement with those reported in the service manual.

Now the bad news.....
I reconnected the SMPS to the mainframe and... nothing happens. No lights, no trace, nothing.
I hear a regular tick tick (it was irregular and random before the cure). So I'm sure that the SMPS is correctly functioning but the service manual does not explain much about how to proceed in this case.

Any idea/suggestion?

Max


Re: [OT] Best glue to repair lifted trace?

 

That's the plan, unfortunately I can't find an acceptable source of
high temperature resistant, electrically insulating epoxy in Austria.
The closest is in Germany, but that's still 10 euro shipping.

On Sat, May 4, 2019 at 2:54 PM Tony Fleming <czecht@gmail.com> wrote:

Glue it back - remove all debris first.
After that I would reinforce the connections with a wire - solder onto
existing traces.

I'm thinking that there is a problem with the connector - why would it
brake in the first place?

On Sat, May 4, 2019 at 7:23 AM cheater cheater <cheater00@gmail.com> wrote:

Here you go! https://imgur.com/gallery/hlUeQKz

On Sat, 4 May 2019, 14:02 Adrian <Adrian@nicol1.org.uk wrote:

okay, help me out here because I'm confused/bemused by 25+ posts about
high temp glue needed to hold down a connector on a PCB so I've
obviously missed something!

First off, am I right in that:

a) A (thru-hole?) internal connector has come off a PCB and busted a
ground pin in the process.

b) It left (one?) other pin still electrically connected to its pad and
trace but those have peeled of the surface of the board.

c) You think can reposition the connector to the board and sort the
ground pin by somehow re-soldering it

d) You believe you can add glue (epoxy) around the connector to secure
it to the PCB.

If the above is correct why do you need glue for a trace that can
withstand soldering temperatures - the trace/PCB bond cannot be adding
to the retention of the connector against connection/disconnection
forces - so why not re-position/solder everything then add the epoxy
when you're done and brush on a bit of conformal coat or wire-tak or
something to protect/secure the 'loose' trace?

BTW you know that saying " A picture is worth a thousand words"? That is
very true in cases like this!

Adrian

On 5/4/2019 9:20 AM, cheater cheater wrote:
Thanks. This is an internal plug which is not accessible from the
outside.

On Sat, May 4, 2019 at 3:06 AM John Kolb <jlkolb@jlkolb.cts.com>
wrote:

After repair, I would suggest a short extension cable left attached to
the equipment, so all plugging/inplugging stresses are moved to the
end
of the extender.

Jophn

On 5/3/2019 6:28 AM, cheater cheater wrote:
I have a piece of equipment where a trace was lifted. The part is
still
attached and I would like to glue it down. The part is a socket for a
cable, and the plug is difficult to insert and remove. I will have to
solder the other pin which is the ground plane, and broke off, so the
glue
has to survive that. I'll also need to add some structural solder on
the
sides. Is cyanoacrylate a good idea here? Anything better than that?
Thanks.






Re: Calibration and full checkout needed - Tek 7000 series

David Berlind
 

John and Harvey, this really great information I wish I had BEFORE I got started acquiring stuff (though all is not lost). To be clear, in terms of acquiring additional scopes or plug-ins, today I already own 2 7603s, a 7603R, a 7633, a 466 (to Harvey's points about the 46x family), a 547(1A4), and a T935. My vertical 7000 plug-ins are a mixture of 7A18's (which get me to 4 channels on a 7000) and 7A15's (the military version). For horizontal, it sounds like a 7A22 and 7A26 would be good to throw on the mix. For the vertical, I have 7B53A's.

I'm curious about your thoughts on the 75Mhz 7A15. Its sensitivity isn't the 10uV of the 7A22, but with its 10x switch, it can apparently go down to 500uV.

Also, why would a 200Mhz 7A26 make sense in a 100Mhz 7603 (if it does)?

I love the Hantek idea.

For DMMs, I have a Fluke 87V and Agilent u1253b already. So I have no immediate needs there.

Ultimately, I want to thin and enhance (ie: plug-ins) my herd down to only that which is necessary (and good enough calibrated) for my applications (again tube amps and radios). At 100Mhz without the flexibility of the plug-ins, my feeling is the 466 is out (also because I don't need storage which is also why the 7633 goes too, vs one of the 7603's).

I haven't played with the 35Mhz T935 yet but really see no need for it. Portability is not an issue for me.

Technically, the 50Mhz 547 seems unjustifiable to keep. Although the TekWiki mentions a cascading option that, if I read it correctly, gets its sensitivity down to 200uV of sensitivity (not as good as the 7A22 for low freq, but better than the 7A15). But I haven't read into it yet. Maybe I have it wrong. In the end, I just may keep the 547 for its sheer beauty.

Finally, the big question (bringing it back to the thread) for me is how badly do I need the stupid money TM500-related calibration gear or is there a short cut with something else that gets me close enough for my application now that I have the signal standardized plug in.

As always, thank you for your feedback.

On May 3, 2019 9:48:48 PM "John Kolb" <jlkolb@jlkolb.cts.com> wrote:

If you go with the 7000 series mainframe, I'd recommend the 7A26 and
7A22 plugins as primary. The 7A26 for frequencies above 1 MHz, and the
7A22 for low amplitude. the 7A22 has sensitivity down to 10uV/div, and
switch selectable high pass and low pass filters for various freqs.
It's been invaluable to me working with low level audio in a system with
lots of high freq digital noise all over.

The 7A13 is great for measuring AC signals accurately or for high freq
signals down to 1 mV/div but for audio work, you are generally
interested in knowing a voltage within 0.1 db than 0.1% voltage accuracy.

I take the vertical output from the 7000 mainframe into a Hantek digital
scope to freeze a signal trace and store to a USB thumb drive for
transfer to a computer for documentation. In my application, the Hantek
picks up so much digital noise to be worthless viewing even high level
signals without filtering through the 7A22 first.

I'd recommend an AN873 DMM, Digital Multimeter. $30 on Amazon, and
specs as good as the Fluke 77-V, $372. The two I have were both within
the 0.05% spec at 10V and 1V DC. As well as AC and DC volts and current
and ohms, it also measures frequency, capacitance, and temperature. The
AC voltage measurement is true RMS, but dies rapidly above 2 kHz.
Plenty good enough to measure AC or DC volts applied to a scope input to
verify scope basic accuracy.

John

On 5/3/2019 7:39 AM, Harvey White wrote:
On Thu, 2 May 2019 19:59:08 -0400, you wrote:

Harvey, to your point about the application, to be clear, my applications
in order of priority are:


1. tube amp repair.. basically an audio application involving low
frequencies. I occasionally end up in solid state land but have had luck
isolating a misbehaving component with old time techniques.
2. vintage radio repair


So, very basic stuff where the exacting accuracy of the oscilloscope may
not be necessary. But I'd like for them to be the ballpark.
Ballpark you can get without special equipment. DMM calibration is
something else, but there are 10 volt very accurate references
available. It's when you star looking at 4 1/2 digits and up where
things start to get tricky with the reference. That's also just DC
volts, AC, ohms, and current are separate matters.

For what you're looking at, you would like to have a 100 Mhz scope, at
least dual channels. If you're doing audio and you want to start
poking around audio preamps, you'd want a fairly sensitive scope to
match the expected signal levels.

5 mv/div may be too little.

For portable scopes, the 465 would do well. If you want digital as an
add-on (either, without forcing you into digital at all times), then a
468 would work well.

IF you want a 7000 series scope, then a 7603 would do well, 7B53
plugin for sweep, 7A26 (two of them) gives you 4 channels, a pair of
7A18's would give you 75 Mhz bandwidth, which would be good enough,
although I'd go for the 7A26 if you get another scope frame.

You might want to look at the 7A13 (I prefer the electronic readout
one), and the 7A22. Both are differential, have some good low ends for
input ranges, and may be more of what you want for debugging preamps.

almost any 10x probe with a 1meg input match on the plugin would work.

If you care to, the 7704 is a 200 Mhz bandwidth scope, and would work
well with the same plugins.

For specialized test equipment, the SG502 is an ultra low distortion
signal generator module, and the AA501 or AA5001 is a distortion
analyzer. Bear in mind that audio enthusiasts have bid up the prices
on these, because price is no object.

Nice to have, though.

a good 4 1/2 digit meter would help, you'd like the full range of AC,
DC, AC current (could be useful) and DC current.

Harvey



On Thu, May 2, 2019 at 7:27 PM Tony Fleming <czecht@gmail.com> wrote:

Sorry for asking this question: What is " levelling head kit" ?
I think it has something to do with calibration....

On Thu, May 2, 2019 at 5:25 PM Craig Sawyers <
c.sawyers@tech-enterprise.com>
wrote:

And you can get a levelling head kit (no housing) for the SG504 from me
...


David
I have one of your kits and have had for quite a while. Just waiting to
find an SG504 without head
that is less than stupid money ;-)

Craig


Re: [OT] Best glue to repair lifted trace?

Adrian Nicol
 

Aha! okay, it looks like the power pins are surface mount so there must be something designed to help add mechanical retention to the PCB as well?

Either way looks like a real easy thing to fix as it aint exactly a fine pitch multi-pin connector!

I would say step one is to clean things up which I think involves (carefully!) unsoldering the remaining pin from the trace so you can get to things. Then I would scrape the solder resist off the copper over the via area(s) and tin it ready for the repair.

If there are retention features, and they are not busted that will make things easier to re-seat the connector body to the board, if not or if they are broken, you could try and find a replacement from Farnell/RS/Digi/whoever but failing that use a bit of epoxy to secure it enough to allow you to repair and re-solder the pins to the traces. I would be using copper foil for that, tin and sweat it on.

I have found that the tacky copper foil sold for RF shielding works well for this as (to my surprise) the glue does not stop you getting a nice bead of solder round the edge and the tackiness holds it in place as you do it!

Then add more epoxy to secure the body if you think it needs it and yopu're done. I really don't think you will find it too difficult to do.

Good luck!

Adrian

On 5/4/2019 1:23 PM, cheater cheater wrote:
Here you go! https://imgur.com/gallery/hlUeQKz

On Sat, 4 May 2019, 14:02 Adrian <Adrian@nicol1.org.uk wrote:

okay, help me out here because I'm confused/bemused by 25+ posts about
high temp glue needed to hold down a connector on a PCB so I've
obviously missed something!

First off, am I right in that:

a) A (thru-hole?) internal connector has come off a PCB and busted a
ground pin in the process.

b) It left (one?) other pin still electrically connected to its pad and
trace but those have peeled of the surface of the board.

c) You think can reposition the connector to the board and sort the
ground pin by somehow re-soldering it

d) You believe you can add glue (epoxy) around the connector to secure
it to the PCB.

If the above is correct why do you need glue for a trace that can
withstand soldering temperatures - the trace/PCB bond cannot be adding
to the retention of the connector against connection/disconnection
forces - so why not re-position/solder everything then add the epoxy
when you're done and brush on a bit of conformal coat or wire-tak or
something to protect/secure the 'loose' trace?

BTW you know that saying " A picture is worth a thousand words"? That is
very true in cases like this!

Adrian

On 5/4/2019 9:20 AM, cheater cheater wrote:
Thanks. This is an internal plug which is not accessible from the
outside.
On Sat, May 4, 2019 at 3:06 AM John Kolb <jlkolb@jlkolb.cts.com> wrote:
After repair, I would suggest a short extension cable left attached to
the equipment, so all plugging/inplugging stresses are moved to the end
of the extender.

Jophn

On 5/3/2019 6:28 AM, cheater cheater wrote:
I have a piece of equipment where a trace was lifted. The part is still
attached and I would like to glue it down. The part is a socket for a
cable, and the plug is difficult to insert and remove. I will have to
solder the other pin which is the ground plane, and broke off, so the
glue
has to survive that. I'll also need to add some structural solder on
the
sides. Is cyanoacrylate a good idea here? Anything better than that?
Thanks.


Re: [OT] Best glue to repair lifted trace?

Tony Fleming
 

Glue it back - remove all debris first.
After that I would reinforce the connections with a wire - solder onto
existing traces.

I'm thinking that there is a problem with the connector - why would it
brake in the first place?

On Sat, May 4, 2019 at 7:23 AM cheater cheater <cheater00@gmail.com> wrote:

Here you go! https://imgur.com/gallery/hlUeQKz

On Sat, 4 May 2019, 14:02 Adrian <Adrian@nicol1.org.uk wrote:

okay, help me out here because I'm confused/bemused by 25+ posts about
high temp glue needed to hold down a connector on a PCB so I've
obviously missed something!

First off, am I right in that:

a) A (thru-hole?) internal connector has come off a PCB and busted a
ground pin in the process.

b) It left (one?) other pin still electrically connected to its pad and
trace but those have peeled of the surface of the board.

c) You think can reposition the connector to the board and sort the
ground pin by somehow re-soldering it

d) You believe you can add glue (epoxy) around the connector to secure
it to the PCB.

If the above is correct why do you need glue for a trace that can
withstand soldering temperatures - the trace/PCB bond cannot be adding
to the retention of the connector against connection/disconnection
forces - so why not re-position/solder everything then add the epoxy
when you're done and brush on a bit of conformal coat or wire-tak or
something to protect/secure the 'loose' trace?

BTW you know that saying " A picture is worth a thousand words"? That is
very true in cases like this!

Adrian

On 5/4/2019 9:20 AM, cheater cheater wrote:
Thanks. This is an internal plug which is not accessible from the
outside.

On Sat, May 4, 2019 at 3:06 AM John Kolb <jlkolb@jlkolb.cts.com>
wrote:

After repair, I would suggest a short extension cable left attached to
the equipment, so all plugging/inplugging stresses are moved to the
end
of the extender.

Jophn

On 5/3/2019 6:28 AM, cheater cheater wrote:
I have a piece of equipment where a trace was lifted. The part is
still
attached and I would like to glue it down. The part is a socket for a
cable, and the plug is difficult to insert and remove. I will have to
solder the other pin which is the ground plane, and broke off, so the
glue
has to survive that. I'll also need to add some structural solder on
the
sides. Is cyanoacrylate a good idea here? Anything better than that?
Thanks.





Re: [OT] Best glue to repair lifted trace?

 

On Sat, 4 May 2019, 14:02 Adrian <Adrian@nicol1.org.uk wrote:

okay, help me out here because I'm confused/bemused by 25+ posts about
high temp glue needed to hold down a connector on a PCB so I've
obviously missed something!

First off, am I right in that:

a) A (thru-hole?) internal connector has come off a PCB and busted a
ground pin in the process.

b) It left (one?) other pin still electrically connected to its pad and
trace but those have peeled of the surface of the board.

c) You think can reposition the connector to the board and sort the
ground pin by somehow re-soldering it

d) You believe you can add glue (epoxy) around the connector to secure
it to the PCB.

If the above is correct why do you need glue for a trace that can
withstand soldering temperatures - the trace/PCB bond cannot be adding
to the retention of the connector against connection/disconnection
forces - so why not re-position/solder everything then add the epoxy
when you're done and brush on a bit of conformal coat or wire-tak or
something to protect/secure the 'loose' trace?

BTW you know that saying " A picture is worth a thousand words"? That is
very true in cases like this!

Adrian

On 5/4/2019 9:20 AM, cheater cheater wrote:
Thanks. This is an internal plug which is not accessible from the
outside.

On Sat, May 4, 2019 at 3:06 AM John Kolb <jlkolb@jlkolb.cts.com> wrote:

After repair, I would suggest a short extension cable left attached to
the equipment, so all plugging/inplugging stresses are moved to the end
of the extender.

Jophn

On 5/3/2019 6:28 AM, cheater cheater wrote:
I have a piece of equipment where a trace was lifted. The part is still
attached and I would like to glue it down. The part is a socket for a
cable, and the plug is difficult to insert and remove. I will have to
solder the other pin which is the ground plane, and broke off, so the
glue
has to survive that. I'll also need to add some structural solder on
the
sides. Is cyanoacrylate a good idea here? Anything better than that?
Thanks.



Re: 1502 HV problem

Tony Fleming
 

I understand Harvey how much work these SALES are. Yes, I also bought
couple old scopes that are not gonna work as once intended, but it is fun
to have them display something and show people that next to Tektronix and
some new scope from today's.
Most people have their mouth open wide, when they learn something like
that, but if I can convert one soul from phone browsing zombies to
electronics, I served my time on this planet well!
Have a great weekend!
Tony

On Fri, May 3, 2019 at 11:45 PM Harvey White <madyn@dragonworks.info> wrote:

On Fri, 3 May 2019 09:52:50 -0500, you wrote:

Harvey, I need to visit you one day, before the sales you go to, so I can
find me some of these DEALS!
It's fun to, it is like a "BOX OF CHOCOLATES, you never know what you
gonna
get".
Hamfests. Mostly hamfests. You have to go to a lot, and you need to
see if there are any electronics surplus stores near you. You will
likely go to quite a few such places before you find much. You're
looking at about fifteen years or so of collecting, and some things
were definitely a "you had to be there, at that time, otherwise no..."
kind of deal.

Bear in mind this, as well. I've got some things I bought that can't
be fixed, or if they are to be fixed, I'm going to have to dump some
money into them because of either special parts or amount of parts to
be replaced.

Some of these things need a lot of work to get back to good shape,
cleaning, testing, calibration.

It's not all deals. I've seen stuff that was really nice, and that
I'd like to have, but were so overpriced as to be silly. From what I
can guess, they went home unbought, too....

You hear about the bargains and lucky finds here. Go back and read
some of the archives and you'll find things that just didn't do all
that well.

Harvey





On Fri, May 3, 2019 at 9:48 AM Harvey White <madyn@dragonworks.info>
wrote:

On Thu, 2 May 2019 18:29:30 -0400, you wrote:

I got this one out of the buck a pound box at a surplus vendor at
Dayton a couple years back. It was functional, just needed a battery
pack and there was a fault in the charging circuitry which I fixed.

The TDs were, miraculously, fine.
Highly fortunate. That's one that nobody has ever found a replacement
for.

My 1502 is sitting on the shelf with its input protector firmly in
place. I was lucky enough to mange to find all of the accessories for
it and a lid as well. Ditto with the 1503. Even though the 1503 is
made for longer cables, I think I'd go with that first since it's far
more difficult to damage.

I've got a 7D02 microprocessor tester that I paid 5 dollars for, so I
know the feeling. It seems to work perfectly except no pods. Oh
well. Ought to be on the lookout for that stuff, too.

The 1502 is nice, the thing that is confusing between the 1502 and
1503 is that while the 1503 has a nice sine squared pulse as the
output (which gives you the classic reflections), the 1502 has a step
riding on top of a waveform, and you look for the corresponding step,
not a sine flavored pulse.

Harvey



The cover was twice what I paid for the unit and the repair parts
are around 3X. Nothing like an excuse to spend money.

Paul


On Thu, May 02, 2019 at 06:20:11PM -0400, Harvey White wrote:
On Thu, 2 May 2019 13:26:17 -0400, you wrote:

Thanks for the reply Harvey. I have a Mouser order in so I'm just
going
to replace all of the HV components and hope the transformer didn't
get
toasted. One of those HV caps has a suspicious appearance around
one of the leads.
I actually had one that had a bad CRT, bad horizontal board, and a
few
problems in the pulse generator (I think it was the 1503). Not sure
what the 1502's problem was, but I actually got one with a good TD.

It may have had the bad HV board.

Harvey



The 6.2M resistor has drifted up to 7.5M in the intensity path, so
replacing that might help a bit too.

Paul

On Wed, May 01, 2019 at 10:58:37AM -0400, Harvey White wrote:
On Tue, 30 Apr 2019 20:44:20 -0400, you wrote:

After accidentally leaving my 1502 on overnight I came back to
find
it dead. I eventually traced it down to a HV problem.

This circuit is so simple it's ludicrous but I'm hampered by
having
lost my HV probe. In any event, the output across the HV
transformer
is a square wave of about 50V; it's supposed to be 500V. If I
disconnect C4328 (connected directly to the transformer), I see
the
expected 500V across the transformer. The HV diodes appear to be
OK,
but something is loading it down. I've disconnected the CRT and
controls with no change, so it has to be on the board.
I repaired my 1502's high voltage section. I saw capacitors that
had
cracked, and the diodes weren't all that happy either. IIRC,
microwave oven diodes work. I just tested and replaced all the
bad
capacitors.


I don't see any unusually low ohm readings either.

Any ideas for tracking down the failed component or should I just
shotgun the multiplier and replace everything? One cap is 0.033
at 600V and the other 3 are 0.027 at 1200V.
It's been noted that sometimes HV capacitors are OK at lower
voltages
and leaky at higher ones.




!DSPAM:5ccb6d29156751858445706!








Re: [OT] Best glue to repair lifted trace?

Adrian Nicol
 

okay, help me out here because I'm confused/bemused by 25+ posts about high temp glue needed to hold down a connector on a PCB so I've obviously missed something!

First off, am I right in that:

a) A (thru-hole?) internal connector has come off a PCB and busted a ground pin in the process.

b) It left (one?) other pin still electrically connected to its pad and trace but those have peeled of the surface of the board.

c) You think can reposition the connector to the board and sort the ground pin by somehow re-soldering it

d) You believe you can add glue (epoxy) around the connector to secure it to the PCB.

If the above is correct why do you need glue for a trace that can withstand soldering temperatures - the trace/PCB bond cannot be adding to the retention of the connector against connection/disconnection forces - so why not re-position/solder everything then add the epoxy when you're done and brush on a bit of conformal coat or wire-tak or something to protect/secure the 'loose' trace?

BTW you know that saying " A picture is worth a thousand words"? That is very true in cases like this!

Adrian

On 5/4/2019 9:20 AM, cheater cheater wrote:
Thanks. This is an internal plug which is not accessible from the outside.

On Sat, May 4, 2019 at 3:06 AM John Kolb <jlkolb@jlkolb.cts.com> wrote:

After repair, I would suggest a short extension cable left attached to
the equipment, so all plugging/inplugging stresses are moved to the end
of the extender.

Jophn

On 5/3/2019 6:28 AM, cheater cheater wrote:
I have a piece of equipment where a trace was lifted. The part is still
attached and I would like to glue it down. The part is a socket for a
cable, and the plug is difficult to insert and remove. I will have to
solder the other pin which is the ground plane, and broke off, so the glue
has to survive that. I'll also need to add some structural solder on the
sides. Is cyanoacrylate a good idea here? Anything better than that? Thanks.

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