Date   
Re: Tek Made Relays

Gordon <tekscopes@...>
 

On 25/04/2017 14:53, Stefan Trethan stefan_trethan@... [TekScopes] wrote:
So that leaves Nylon, or maybe the "blue flame" was not correct?
They're glued really well so that pretty much rules out nylon.

Gordon

Re: Tek Made Relays

stefan_trethan
 

Delrin burns with a yellow flame.

It could by Nylon with a blue flame, TPX (Polymethylpentene) or PE/PP
(unlikely).
My money would be on TPX, just because it is weird enough for Tek, but
that is transparent and I do not think they make it white?

So that leaves Nylon, or maybe the "blue flame" was not correct?

Delrin does degrade outdoors into the hard crumbling substance
described, more so the white variety.
I don't know if, given enough time, that will happen without light too.

ST



On Mon, Apr 24, 2017 at 11:14 PM, 'Dennis Tillman' @Dennis_Tillman_W7PF
[TekScopes] <TekScopes@...> wrote:
Hi David,
You co-worker might have been mistaken. That doesn't sound like Delrin at
all. Delrin is a wonderful plastic and as far as I know it is stable and a
dream to machine. One way to tell if it was Delrin is that Delrin is almost
as slippery as Teflon.

This is what one plastics provider said about Delrin
(http://www.sdplastics.com/delrin/delrin[1].pdf):

Delrin is a crystalline plastic which offers an excellent balance of
properties that bridge the gap between metals and plastics. Delrin possesses
high tensile strength, creep resistance and toughness. It also exhibits low
moisture absorption. It is chemically resistant to hydrocarbons, solvents
and neutral chemicals. These properties along with its fatigue endurance
make Delrin ideal for many industrial applications. Parts exposed to a moist
or wet environment, such as pump and valve components, are especially
appropriate. Other common uses for Delrin include gears, bearings, bushings,
rollers, fittings and electrical insulator parts.

Dennis Tillman W7PF

-----Original Message-----
Sent: Monday, April 24, 2017 1:57 PM
Subject: Re: [TekScopes] Tek Made Relays

When I was a newbie at Tek, a coworker referred to the material as Delrin.

He went on to say that Tek had discontinued that style of relay, replacing
them for safety and liability reasons with purchased parts. "They burn with
a beautiful blue flame," he said wryly.

Dave Wise
Information Display 1980-1995
________________________________________
From: TekScopes@... <TekScopes@...> on behalf of
Chuck Harris cfharris@... [TekScopes] <TekScopes@...>
Sent: Monday, April 24, 2017 12:10 PM
To: TekScopes@...
Subject: Re: [TekScopes] Tek Made Relays

The big problem I have seen with some tek made relays is they made an
unfortunate choice of plastics for the relay case. The plastic they used
breaks down into something that is fragile, and emits corrosive gasses.
The gasses corrode the relay armature, and make it stick open or closed.

-Chuck Harris



------------------------------------
Posted by: "Dennis Tillman" <@Dennis_Tillman_W7PF>
------------------------------------


------------------------------------

Yahoo Groups Links


Re: Tek Made Relays

cmjones01
 

On 25 Apr 2017 3:35 p.m., "Chris Jones" <chris@...> wrote:



On 25 Apr 2017 7:05 a.m., "Dave Seiter d.seiter@... [TekScopes]" <
TekScopes@...> wrote:




Is there a visual way to tell the difference between the 600 and 1000 ohm
relays?
-Dave


I repaired/replaced some faulty relays in my 7A13 plugins and they were
labelled '500 ohm' (using the omega symbol for ohms) near the top, above
the pinout diagram, though the print rubs off rather easily.

Typo! I mean 600 ohm...

Chris

Re: Tek Made Relays

cmjones01
 

On 25 Apr 2017 7:05 a.m., "Dave Seiter d.seiter@... [TekScopes]" <
TekScopes@...> wrote:




Is there a visual way to tell the difference between the 600 and 1000 ohm
relays?
-Dave


I repaired/replaced some faulty relays in my 7A13 plugins and they were
labelled '500 ohm' (using the omega symbol for ohms) near the top, above
the pinout diagram, though the print rubs off rather easily.

Chris

Re: TDS744A input failure.

Siggi
 

On Tue, 25 Apr 2017 at 06:25 David @DWH [TekScopes] <
TekScopes@...> wrote:

The TDS520B service manual shows the 50 ohm termination before the

high impedance attenuators but I do not see how that could apply to
the 1 GHz versions.
The 1 GHz scopes use the same attenuator modules. People have successfully
"upgraded" e.g. the 500 MHz/2 GS TDS754 to 1 GHz/4 GS TDS784-equivalent.
The 2/3 GHz 694 uses 50Ohm-only input attenuators that are presumably of a
more exacting design. Presumably the transmission line stubs that the
relays and high-impedance attenuators make become unworkable somewhere
beyond 1 GHz.

Re: Tek 465 multiplier

Mark Wendt
 

On 04/25/2017 08:52 AM, Göran Krusell mc1648pp@... [TekScopes] wrote:
The LTspice tool will show you all node voltages in your design. And then
you can set your
component requirements. Easy.

Göran
I know what LTSpice is and does. What I didn't know was what you were replying to and what was being verified. You didn't quote anything from the post you were replying to, so other than you, nobody really knows what the gist of the conversation is about.

Notice I quoted your reply so people know what I'm reply to.

Mark

Re: Tek 465 multiplier

Göran Krusell
 

The LTspice tool will show you all node voltages in your design. And then
you can set your
component requirements. Easy.

Göran


[Non-text portions of this message have been removed]

Re: 576 erratic brightness

Chuck Harris
 

I think the issue isn't the added diode, but rather the series
of manuals that didn't make the box outlines bold, and break them
around the terminal points that were denoted by a black dot.

In those few manuals, and the 576 manual found on ebaman.com is one,
the box outline was the same width line as the circuit wiring, and
the dots were slightly larger than the connection dots.

When the formerly blue, outline boxes are printed in black, they
look like some very strange, nay, insane, circuit connections. In
simple places like the intensity pot in question, one might think
that they were actual wiring, and the pot was redundant.

In other places, where the outline box crossed all of the leads on
a power supply, and made it look like all of the power supply outputs
were shorted together, one gets the idea fairly quickly...

The tektronix blue color choice used to be quite a problem back when
all copies were made on the old xerographic process copier machines,
as the copier drums weren't at all sensitive to blue light.... which
caused the blue lettering to totally disappear in the copy.

In scans where the person scanning the schematic chose "B&W Line art"
as the scanning method, a rigid threshold is used to decide whether
a point on the paper is white or black, and the blue lines either
disappear as being below the threshold, or are totally black when
they are above the threshold.

-Chuck Harris

hahi@... [TekScopes] wrote:

Can somebody with a paper copy of the manual upload a scan or a photo
As Chuck pointed out Tek often used print in blue to indicate changes on schematics.
However in this manual the change was instead in weak grey. It is an original manual
and not a scan rev 7-83. In the newer manual I have the print is even weaker.

You can find a photo of the page here:

http://www.hakanh.com/dl/temp/576.jpg http://www.hakanh.com/dl/temp/576.jpg

/Håkan

Re: Tek 465 multiplier

Mark Wendt
 

On 04/25/2017 07:04 AM, Göran Krusell mc1648pp@... [TekScopes] wrote:
Hi,
yes, and this can be easily verified by using the LTspice simulation tool,
one of my favorite tools and also free.

Göran

What can be verified?

Mark

Re: TDS744A input failure.

stefan_trethan
 

Maybe you still have leakage currents from the electrolyte?
I washed the boards of my TDS544A really well with water and detergent.
Obvously I rinsed them to get the detergent off, and dried them before use.

ST


On Tue, Apr 25, 2017 at 2:19 PM, 'Daveyk021 .' daveyk021@...
[TekScopes] <TekScopes@...> wrote:
Thank you. On my TDS544, I now have all four traces but the compensation
routine does not work, it ends in an error. Channel 1 and 2 are pretty
close but float from 0v a little. Traces 3 and 4 are pretty high above the
0v baseline.

Yesterday, I had a ACQ board out and examined every trace from every cap.
I found two questionable solder connections to the caps. There is not a
lot of leakage damaged to the board. I have cleaned all leaked areas (and
there was really only 3) with flux remover. I have flushed the entire
board with flux remover. All op amps have proper voltage rails.

I checked all the voltages coming out of the power supply and they are spot
on. What I didn't do was scope them for noise.

I'm not sure where to test the ACQ board for this problem. I tired to
include a picture of the ERROR screen of the scope and that didn't stay
with the email. I tried to upload the picture to the file upload section
and the upload does not complete. Some of the messages:
"ERROR: Cal meas clipped at max dig g... CH3 Balance Cal of Attenuator"
"ERROR: Insufficient differential responce CH1 Gain cal of M694 Stepgains"
"ERROR: Characterized values out of b...A/D biasing cal"
"ERROR: Characterized values out of b...Vertical"
"ERROR: 2260 Calibration failed"
"ERROR: 2260 Calibration failed"
...

Dave

On Tue, Apr 25, 2017 at 6:12 AM, David @DWH [TekScopes] <
TekScopes@...> wrote:



There is a TDS520B service manual which includes schematics giving a
good idea of what is in the attenuator hybrids.

http://bee.mif.pg.gda.pl/ciasteczkowypotwor/Tek/ds520b-cm.pdf

On Mon, 24 Apr 2017 14:55:14 -0400, you wrote:

Are there schematics for those input boards/hybrids? With those somewhat
large relays soldered on them, I don't exactly think of them as hybrids.
If
they considered that, my guess is "no"?





------------------------------------
Posted by: "Daveyk021 ." <daveyk021@...>
------------------------------------


------------------------------------

Yahoo Groups Links


Re: TDS744A input failure.

David Kuhn
 

Thank you. On my TDS544, I now have all four traces but the compensation
routine does not work, it ends in an error. Channel 1 and 2 are pretty
close but float from 0v a little. Traces 3 and 4 are pretty high above the
0v baseline.

Yesterday, I had a ACQ board out and examined every trace from every cap.
I found two questionable solder connections to the caps. There is not a
lot of leakage damaged to the board. I have cleaned all leaked areas (and
there was really only 3) with flux remover. I have flushed the entire
board with flux remover. All op amps have proper voltage rails.

I checked all the voltages coming out of the power supply and they are spot
on. What I didn't do was scope them for noise.

I'm not sure where to test the ACQ board for this problem. I tired to
include a picture of the ERROR screen of the scope and that didn't stay
with the email. I tried to upload the picture to the file upload section
and the upload does not complete. Some of the messages:
"ERROR: Cal meas clipped at max dig g... CH3 Balance Cal of Attenuator"
"ERROR: Insufficient differential responce CH1 Gain cal of M694 Stepgains"
"ERROR: Characterized values out of b...A/D biasing cal"
"ERROR: Characterized values out of b...Vertical"
"ERROR: 2260 Calibration failed"
"ERROR: 2260 Calibration failed"
...

Dave

On Tue, Apr 25, 2017 at 6:12 AM, David @DWH [TekScopes] <
TekScopes@...> wrote:



There is a TDS520B service manual which includes schematics giving a
good idea of what is in the attenuator hybrids.

http://bee.mif.pg.gda.pl/ciasteczkowypotwor/Tek/ds520b-cm.pdf

On Mon, 24 Apr 2017 14:55:14 -0400, you wrote:

Are there schematics for those input boards/hybrids? With those somewhat
large relays soldered on them, I don't exactly think of them as hybrids.
If
they considered that, my guess is "no"?

Re: Type 503 Oscilloscope Issues

Dave Casey
 

That's certainly an option. You could also spend more time making
measurements to verify that V620 is the problem. The carbon composition
resistors used in electronics of this era tend to drift high over time,
especially if stored at high humidity. It's likely that several resistors
in the scope are out of spec, including those around V634 and V620.

Dave Casey

On Apr 25, 2017 1:31 AM, "enchanter464@... [TekScopes]" <
TekScopes@...> wrote:



Sorry Dave, I'm afraid that I do not have a replacement tube to test with.
I only found out recently that the other analog scopes I had mentioned were
removed by the department earlier this year to make everything digital (and
to free up storage space). I am not sure if they were transferred
elsewhere, or more likely, just discarded. However, I can easily order a
new tube, which would be good to have on hand anyway.

Evan

Re: Tektronix 465B probes,

 

The most general purpose probes for the 465B are passive high
impedance x10 probes with a bandwidth of 100 MHz or higher. Passive
high impedance x1 probes can be used for higher sensitivity but are
limited to low bandwidth.

I have a bunch of these and they work well enough although the x1/x10
switch on the probe body seems to fail after a couple years:

<http://www.ebay.com/itm/2x-100MHz-Oscilloscope-Scope-analyzer-Clip-Probe-test-leads-kit-for-HP-Tektronix-/151894560636>

These probes made by Texas (based in Hong Kong) are better and made by
the same company that OEMs probes for Keysight and other
manufacturers. I bought them for the readout support:

<http://www.ebay.com/itm/One-new-250MHZ-Oscilloscope-clip-probe-w-readout-pin-X10-Tektronix-HP-RIGOL-/280107318452>

These might be good and are probably what I would try next time for my
100 MHz oscilloscopes:

<http://www.ebay.com/itm/Texas-1X-10X-150Mhz-Oscilloscope-Probe-with-original-accessories-Hook-Ground-/152512383122>

On 25 Apr 2017 00:02:44 +0000, you wrote:

Hello,
I wanted to say hi to everyone here, And thank you for letting me join the group, I just bought my first oscilloscope a 465B. I will be using it to troubleshoot my yaesu ft-102 HF transceivers, It did not come with any probes, Can someone tell me what type of probes i should buy to work on HF radios. Your help is greatly appreciated Thank you for your time,

Re: Tek 465 multiplier

Göran Krusell
 

Hi,
yes, and this can be easily verified by using the LTspice simulation tool,
one of my favorite tools and also free.

Göran


[Non-text portions of this message have been removed]

Re: Tek 465 multiplier

 

Thanks for bringing this up. The capacitors and diodes need to handle
the peak to peak input voltage which of course means they need to
handle more than that for reliability.

On Mon, 24 Apr 2017 17:37:04 -0300, you wrote:

Hello David,

Sticking up my nose...

It grabbed my attention that Sam mentioned in his initial post he'd be
using 3kV caps and I`m confused about that...

Isn't it that the capacitors need to withstand the peak-to-peak voltage
(i.e. 5kV) ?

As I saw it, I got doubtful if it's the peak voltage or peak-to-peak...

If it's peak-to-peak, I suppose he need to use - at least - 6.8kV caps.

Rgrds,

Fabio

Re: 475a no trace

 

On Mon, 24 Apr 2017 20:30:40 +0000, you wrote:

was using my scope the other day and it just quit showing a trace, so i cracked it open and started looking around, and found the -8vdc rail to be in the mv range.

so i start out at U1464A and see that pin3 is in mv range so i look at R1464 and see on the far side its 50v but the closer side is in mv range, so i check it in circuit and don't really get a good resistance reading, so i yank it out and its bang on at 50K, so i put it back in and low and behold i have trace back, turn it off for dinner, and come back and turn it on and its back to no trace.

rechecking things after shutting off then turning back on i see that R1464 far side is still the 50v as it should be, but now on the closer side of that resistor is 6v.

so what could be the issue? a capacitor? or?
6 volts on pin 3 just means that the feedback divider is working and
the output is 0 volts.

So the output is stuck at 0 volts either because the output of the
regulator is not working or because there is a short on the output.

Measure the voltage across R1468 to find the output current. If the
output current is high, probably about 1/2 amp, then there is a short
on the output which is a common problem; look for a shorted solid
tantalum capacitor.

Re: TDS744A input failure.

David Slipper
 

Many thanks - When I'm feeling brave I'll have a "furkle" around the attenuators.

On 25/04/2017 11:25, David @DWH<mailto:@DWH> [TekScopes] wrote:


On Mon, 24 Apr 2017 19:21:38 +0000, you wrote:

There are high impedance attenuators (3?) between the coupling
capacitor and the buffer circuits. If the measured input resistance
is 139 ohms at all vertical sensitivity settings, then the fault has
to be before the high impedance attenuators. If the input resistance
changes with different vertical sensitivity settings, then the fault
is after the high impedance attenuators.
The input resistance is constant - irrespective of the vert sens settings.
So I guess it's before the high impedance attenuators.
Yes, so I think it is before the high impedance attenuators.

The TDS520B service manual shows the 50 ohm termination before the
high impedance attenuators but I do not see how that could apply to
the 1 GHz versions.

Didn't you say that the baseline trace is stuck at ground instead of
having any significant offset? Maybe the 1 megohm shunt resistor
shorted somehow. If so that should be visible on the hybrid.
I don't think I said that - not sure I understand.
Is there a significant DC offset that changes or does not change with
vertical sensitivity.

Interestingly, I came across this in my searching :-

<http://www.eevblog.com/forum/testgear/tektronix-tds520b-attenuator-swap/><http://www.eevblog.com/forum/testgear/tektronix-tds520b-attenuator-swap/>

He seems to have exactly the same issue - even to very similar resistances. But in his
case when he swapped attenuators the problem disappeared - which smells
of a bad connection to me.

Many thanks,
Dave
I am thinking that the relays are not switching and that the problem
is an open circuit between the relays and relay drivers so they are
stuck in an unusable state. At least that could be easy to fix; clean
the contacts between the module and printed circuit board.

Re: TDS744A input failure.

 

On Mon, 24 Apr 2017 19:21:38 +0000, you wrote:

There are high impedance attenuators (3?) between the coupling
capacitor and the buffer circuits. If the measured input resistance
is 139 ohms at all vertical sensitivity settings, then the fault has
to be before the high impedance attenuators. If the input resistance
changes with different vertical sensitivity settings, then the fault
is after the high impedance attenuators.
The input resistance is constant - irrespective of the vert sens settings.
So I guess it's before the high impedance attenuators.
Yes, so I think it is before the high impedance attenuators.

The TDS520B service manual shows the 50 ohm termination before the
high impedance attenuators but I do not see how that could apply to
the 1 GHz versions.

Didn't you say that the baseline trace is stuck at ground instead of
having any significant offset? Maybe the 1 megohm shunt resistor
shorted somehow. If so that should be visible on the hybrid.
I don't think I said that - not sure I understand.
Is there a significant DC offset that changes or does not change with
vertical sensitivity.

Interestingly, I came across this in my searching :-

<http://www.eevblog.com/forum/testgear/tektronix-tds520b-attenuator-swap/>

He seems to have exactly the same issue - even to very similar resistances. But in his
case when he swapped attenuators the problem disappeared - which smells
of a bad connection to me.

Many thanks,
Dave
I am thinking that the relays are not switching and that the problem
is an open circuit between the relays and relay drivers so they are
stuck in an unusable state. At least that could be easy to fix; clean
the contacts between the module and printed circuit board.

Re: TDS744A input failure.

 

There is a TDS520B service manual which includes schematics giving a
good idea of what is in the attenuator hybrids.

http://bee.mif.pg.gda.pl/ciasteczkowypotwor/Tek/ds520b-cm.pdf

On Mon, 24 Apr 2017 14:55:14 -0400, you wrote:

Are there schematics for those input boards/hybrids? With those somewhat
large relays soldered on them, I don't exactly think of them as hybrids. If
they considered that, my guess is "no"?

Re: 576 erratic brightness

 

Can somebody with a paper copy of the manual upload a scan or a photo
As Chuck pointed out Tek often used print in blue to indicate changes on schematics.
However in this manual the change was instead in weak grey. It is an original manual
and not a scan rev 7-83. In the newer manual I have the print is even weaker.

You can find a photo of the page here:

http://www.hakanh.com/dl/temp/576.jpg http://www.hakanh.com/dl/temp/576.jpg

/Håkan