Date   

min loads and extenders available

 

Hi,

Just a heads up. I now have 7K extenders and 2465 min loads available on ebay.
Contact me off list for group discounts.
j_massengale@aol.com

Jerry Massengale


Re: 454 LV Regulator Repair

Roger Evans
 

My 454 has a similar problem with the Ch1 variable control. There is a flexible coupling (nylon I think) just before the shaft of the pot and this has developed a crack in such a way that the pressure of the grub screw is not transferred to the shaft, the nylon bends instead. Also the shaft is tight so that the coupling slips. Tightening the brub screw just bends the nylon even more. The best I could do was get it in the calibrated position and leave it there. Replacing the nylon coupling looks like a major strip down but I would be delighted if anyone knows better!

Roger


Re: TDS684C won't boot up - front panel lights stay on

Ryan Scott
 

An update.  I pulled the front panel assembly and took a look and like I said earlier, nothing seemed out of place.  I did notice some crud around the scale encoders.  Perhaps someone used some contact cleaner on it?  Cleaned it with IPA and after 2 power cycles, it's booted just fine off and on for the last week.  Not really sure what to make of this.  It was 'scrapped' at my work from a remote design center as 'unrepairable'.  The back cover (collar) was missing so it's obvious someone was into it.  From the limited troubleshooting guide I found, everything pointed to the front panel.  The clock signal and all PS voltages were present.  The only thing I can think of is whatever someone may have used to clean the control or whatever crud I found was leaky and causing the boot sequence to hang?  
So far I've ran it through various exercises and it's all good. It's a great scope.  So I guess I'm going to run with it.  
Question:  It takes about 30 sec to boot up.  Front panel lights, then screen flashes, then a 'clock' then clicking followed by the starting screen saying it's passed the power on self test.  
Is this a normal boot time?  (I'll verify it on a 784 at work tomorrow)
Thanks for the time guys.

On Friday, February 13, 2015 8:42 AM, "acuffe@gmail.com [TekScopes]" <TekScopes@yahoogroups.com> wrote:


  I would start by going over the power supply for obvious problems. Even though the SMD caps aren't leaking, it wouldn't hurt to check them for ESR if you can. The caps could have dried out if it was used or stored in a hot location.

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

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


Re: Largest Tube Count Oscilloscope

Kurt Rosenfeld
 

That is the first 517 I've seen working. Congratulations!

On Tue, Feb 17, 2015 at 4:49 PM, snapdiode@yahoo.com [TekScopes] <
TekScopes@yahoogroups.com> wrote:



Yikes. 100A at 6.3? One hopes that's split up among several secondaries as
well as some 12V ones...

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



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


Re: 485 how to get the front panel off?

 

Congratulations, Siggi, well done.
Thanks for sharing this!

Raymond


tds540 repair

drforbin
 

Hi all...
I'm new to the forum and would like to say hello.


I'm currently fixing a tds540.

When I run SPC I'm getting insufficient differential response.

I made some videos which I placed on the tek fourm about the entire repair.
If any of you could help it would be great...

thank you...


All the errors I'm getting now are on the third video.

The first two detail me fixing the sram problem etc.

CAM00241.mp4 https://drive.google.com/file/d/0B1c_4f0VAtfUQTdCVWgxMHRyRFk/view?pli=1

https://drive.google.com/file/d/0B1c_4f0VAtfUQTdCVWgxMHRyRFk/view?pli=1

CAM00241.mp4 https://drive.google.com/file/d/0B1c_4f0VAtfUQTdCVWgxMHRyRFk/view?pli=1


View on drive.google.com https://drive.google.com/file/d/0B1c_4f0VAtfUQTdCVWgxMHRyRFk/view?pli=1
Preview by Yahoo



CAM00242.mp4 https://drive.google.com/file/d/0B1c_4f0VAtfUU3BCVzEzMjR5T2M/view?pli=1

https://drive.google.com/file/d/0B1c_4f0VAtfUU3BCVzEzMjR5T2M/view?pli=1

CAM00242.mp4 https://drive.google.com/file/d/0B1c_4f0VAtfUU3BCVzEzMjR5T2M/view?pli=1


View on drive.google.com https://drive.google.com/file/d/0B1c_4f0VAtfUU3BCVzEzMjR5T2M/view?pli=1
Preview by Yahoo


CAM00246.mp4 https://drive.google.com/file/d/0B1c_4f0VAtfUdVZlNzRldnc1UkE/view?pli=1


https://drive.google.com/file/d/0B1c_4f0VAtfUdVZlNzRldnc1UkE/view?pli=1

CAM00246.mp4 https://drive.google.com/file/d/0B1c_4f0VAtfUdVZlNzRldnc1UkE/view?pli=1


View on drive.google.com https://drive.google.com/file/d/0B1c_4f0VAtfUdVZlNzRldnc1UkE/view?pli=1
Preview by Yahoo


Thank you (Re: Shipping preference: plug-ins in, or plug-ins out?)

Brad Thompson <brad.thompson@...>
 

On 2/17/2015 12:29 PM, Stefan Trethan stefan_trethan@gmx.at [TekScopes] wrote:
The scope without the plug-ins is much weaker structurally.

Use the space and effort you save for better padding and leave them in.
Hello--

My thanks go to Stefan, David and John for their comments regarding shipment
methods for a "loaded' 79xx scope-- I'll pass along their replies.

73--

Brad AA1IP


Re: Largest Tube Count Oscilloscope

snapdiode
 

Yikes. 100A at 6.3? One hopes that's split up among several secondaries as well as some 12V ones...


Re: Largest Tube Count Oscilloscope

mattko87
 

about 600 watts for filaments, measuring by my 517A

german writting topic about 517A´s restoring (not finished, instabilite triggering and timebase)
Forum | Oszilloskope scopes | Tektronix 517A | Wellenkino.de http://www.wellenkino.de/forum/thread.php?board=1&;thread=166

http://www.wellenkino.de/forum/thread.php?board=1&;thread=166

Forum | Oszilloskope scopes | Tektronix 517A | Wellenkin... http://www.wellenkino.de/forum/thread.php?board=1&;thread=166 Tektronix 517A Antwort schreiben Optionen absteigende Reihenfolge 1 2 3 03.02.15 19:07 Matt Administrator Tektronix 517A Mit falsche Netzlampe u...



View on www.wellenkino.de http://www.wellenkino.de/forum/thread.php?board=1&;thread=166
Preview by Yahoo




Oil-transformer is opening and repaired by me (bad paper capacitor) and is refilling with good used mineral-oil.



Oil in high voltage transformer is not orginal, twostroke-oil *dafuq*.
Pleas don't making a discussion over pcb-oil, i have no mood about this thing.
But two bathtub capacitor has pcb and is kicking out by me.

Best regards
Matt


Re: Shipping preference: plug-ins in, or plug-ins out?

stefan_trethan
 

The scope without the plug-ins is much weaker structurally.

Use the space and effort you save for better padding and leave them in.

ST

On Tue, Feb 17, 2015 at 4:17 PM, Brad Thompson
brad.thompson@valley.net [TekScopes] <TekScopes@yahoogroups.com>
wrote:

Hello--

Someone not on this list asked me about the best way to ship a heavy
78xx or 79xx four-bay
scope and its complement of plug-ins: should the plug-ins be left in the
mainframe, or
removed, separately wrapped and shipped in the carton along with the
mainframe?

My instinct would be to recommend putting each plug-in in an antistatic
bag and
separately shrouded in bubble-plastic wrap. I told the inquirer that
everything could
travel in one carton, provided that the scope and plug-ins were suitably
padded
(foamed-in-place would be ideal) and housed in an inner carton padded within
a heavy-walled outer carton.

Comments, anyone? The inquirer pushed back regarding packaging and
shipping costs.

Thanks, and 73--

Brad AA1IP


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

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


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

Yahoo Groups Links



Want to buy - 370 (A) curve tracer bits please

alan.ainslie@...
 

I lost the transparent cover for the test bay in my curve tracer 370A. Is there a spare lying around please?


Also looking for test jigs for pair of TO3, TO66, TO220 and short lead transistors, in fact anything as my adapters cannot be found either.


Very long shot ... Anyone with a spare panel for the right hand side next to the test bay - where the LEFT/RIGHT selector switches locate?


l am located in UK but have a USA ship address.


Many thanks


Alan


Re: Shipping preference: plug-ins in, or plug-ins out?

David DiGiacomo
 

Definitely ship with plugins in. Shipping loose plugins in the same
box with a mainframe seems like a really bad idea, no matter how good
the packaging is. (Note that FedEx and UPS give a discount for a
multi-box shipment to the same place, so putting everything in one
carton won't save money either.)


Re: Shipping preference: plug-ins in, or plug-ins out?

John Griessen
 

On 02/17/2015 09:59 AM, John Griessen wrote:
The important thing is the corners and the distance of springy shock absorbing material,
and is the springy material matched to the weight.
I forgot to mention the distance. I like a 3 inch minimum on all six box faces.
Only with good dense polyurethane foam. More if paper wads, or wimpy foam or bubble pack.
If something like bubble pack is used, or paper wads, be sure it is tight crammed
and taped so it can't move much if possible.
Never use peanuts -- disaster will strike.


Re: Shipping preference: plug-ins in, or plug-ins out?

John Griessen
 

On 02/17/2015 09:17 AM, Brad Thompson brad.thompson@valley.net [TekScopes] wrote:
Comments, anyone? The inquirer pushed back regarding packaging and
shipping costs.
Leaving the plugins in their slots will be OK. The inner box can even be left off.
A slab of Styrofoam as thick as the knob projection distance will be good if you carve out
for the knobs. Just push it lightly against them, then carve where you see marks.
On the front face, that styro is not all -- just outside that put springy foam.

The important thing is the corners and the distance of springy shock absorbing material,
and is the springy material matched to the weight.

What I've seen match fairly well is dense polyurethane foam. Styrofoam is so dense it will
not compress much and so the shock (acceleration levels) of impact on concrete from 5 feet up
will jar the scope more. Corner protectors made of denser material, such as stacked 90 degree
corners of corrugated with a little bubble pack interleaved are good for 60 lbs landing on a corner.
The corners are what gets damaged so prop the scope housing up with them all the way to the external
corrugated box corner, and put some likewise on top corners since no telling which end will be up.

As the overall weight changes, all of this changes, so does not apply to two scopes in one box.
Keep it one per box.
More than two scopes and freight makes sense. Put them on pallet -- make a protective box around them
without falling concern, just toughness from being pushed on or stacked on, and strap that to the pallet tight.
Inside, some foam or paper wads to absorb jolts of pallet touching down.


Re: looking for 2 tubes 8416

Kurt Rosenfeld
 

Historic authenticity is sometimes a concern when making repairs to an
instrument. Other times, one just wants to get it working properly with
whatever parts are on hand. This can become a philosophical issue, but I
want to point out that Tek engineers were not at all sentimental about the
use of tubes. As soon as transistors developed to be a more rational
choice in a given application, Tek engineers used transistors. And there
was a time in the middle, like the 545B vertical amp, which mixes both.

In many cases, a JFET can be used in place of a simple cathode follower
tube. However, using JFETs in place of V44 in the 1S1 would require more
thought since the 8416 tubes were biased with more plate-to-cathode voltage
than a common low-voltage JFET (e.g., MPF102) can handle.

V183A and V183B in the 1S1 can probably be replaced by two high voltage NPN
transistors with no other circuit modification. The base current of the
transistors would be about 10uA, not enough to drag down the bias point.
The difference between Vbe of the transistors versus the grid-to-cathode
voltage of the tubes will result in the common-mode voltage of the signal
(plug-in connector pins 1 & 3) sent to the mainframe being about 60V
instead of 67V, which is probably ok. If not, small circuit changes could
compensate.

-Kurt

On Tue, Feb 17, 2015 at 9:15 AM, Martin Mehlhose murks24@live.de
[TekScopes] <TekScopes@yahoogroups.com> wrote:



they are sick in the head..
This tubes are made to work in a Tek, nothing else.

greetings
Martin

From: mailto:TekScopes@yahoogroups.com
Sent: Tuesday, February 17, 2015 2:50 PM
To: TekScopes@yahoogroups.com
Subject: Re: [TekScopes] Re: looking for 2 tubes 8416

The audiophools discovered the 8416 a few years ago, and of course
someone decided it was the best sounding tube you could ever use. Better
than a 6DJ8, so of course prices went up to match their audio supremacy.

Chuck

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

yes that is 12DJ8.
In the bay they need a shameless money for them...
If it will not be possible to get them I will modify the plugin to use
6DJ8 there

greetings
Martin

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



Shipping preference: plug-ins in, or plug-ins out?

Brad Thompson <brad.thompson@...>
 

Hello--

Someone not on this list asked me about the best way to ship a heavy 78xx or 79xx four-bay
scope and its complement of plug-ins: should the plug-ins be left in the mainframe, or
removed, separately wrapped and shipped in the carton along with the mainframe?

My instinct would be to recommend putting each plug-in in an antistatic bag and
separately shrouded in bubble-plastic wrap. I told the inquirer that everything could
travel in one carton, provided that the scope and plug-ins were suitably padded
(foamed-in-place would be ideal) and housed in an inner carton padded within
a heavy-walled outer carton.

Comments, anyone? The inquirer pushed back regarding packaging and shipping costs.

Thanks, and 73--

Brad AA1IP


Re: 7854 IC chips

 

I know the 7904 uses it, maybe others as well.

Raymond


Re: 7854 IC chips

Albert Otten
 

That SMPS control IC is not specific to the 7854.
Albert


Re: 485 how to get the front panel off?

Siggi
 

On Fri, Feb 6, 2015 at 9:26 AM, hewpatek@gmail.com [TekScopes] <
TekScopes@yahoogroups.com> wrote:

Hi Siggi,
Did you try exercising the switch 10 - 20 times or more? The contact may
improve or even recover by that.
I tried that, no go. Incidentally I've only ever seen that with contacts
that go intermittently open, this guy stays closed, refusing to open.


Otherwise, you may want to remove the front plate after all or risk
damaging it. It's not that much of a hassle.
I started on this yesterday, got the 10-turn pot off, but then I was
confounded by the grounding lug. Looks like an 8mm retaining nut on there,
but I couldn't get any of my tools around it.

In the end I managed to get the pot free with a pair of angled long-nose
pliers, and fish it up by its wiring harness. The switch was bad, and even
after dismantling the pot, I couldn't see any reasonable way to get into
that segment to tweak it. Thankfully there was an unused extra NO/NC switch
segment, and I could just move the appropriate wires there.


7854 IC chips

Clint
 

Anyone have 155-0067-02 ic chips for sale?




Sent from my iPad

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