Date   

Re: 560 Series Plugin Dimensional Drawings

David Holland
 

Thanks, there were a few in there..... At least enough to confirm that my
seldom used (and cheap) calipers weren't completely whacked....

Additionally, I learned what the little plastic tab in back, on the bottom,
is really for. 560 power supply compatibility, and not just they stand up
on their backs better in one position than the other. :-)

Cheers,

David


On Wed, Apr 21, 2021 at 10:57 PM snapdiode via groups.io <snapdiode=
yahoo.com@groups.io> wrote:

There might be some dimensions here

https://w140.com/tekwiki/wiki/040-0245-00






Re: 485 super weak brightness control

Ondrej Pavelka
 

Guys,

New Relays arrived and nearly all is healed. When B is selected all works
flawlessly, when A is selected everything works up till the 521 range. In
521 it's not displaying properly. More in the video

I'm so happy it's nearly there now!

https://youtu.be/xCO4kJbXaMw

On Fri, 26 Mar 2021, 01:21 Raymond Domp Frank, <hewpatek@gmail.com> wrote:

On Fri, Mar 26, 2021 at 12:48 AM, Ozan wrote:


I agree sometimes stepping back and looking with fresh eyes helps. Let
us know
when you want to bounce off ideas again.
Ozan
I fully concur, Ozan.

Raymond






Re: Alert for 519 owners - The significance of the Gold GR Connectors

Egge Siert
 

Hi to All,

With SN 1020 and higher the Outer Connectors are Gold Plated. Just readed it in the Manual (Mechanical Parts List).

Greetings,

Egg Siert


Re: 560 Series Plugin Dimensional Drawings

snapdiode
 

There might be some dimensions here

https://w140.com/tekwiki/wiki/040-0245-00


Re: Free new Tek 152-0383-00 SMTD-898 Tunnel Diode

snapdiode
 

The diode is missing. I would like a real Tek part.


Re: PG506 Repair - I had a Great Day today/

tek_547
 

That is really a very detailed explanation Michael, very much thanx for that! In the weekend or next week I have the time to work on the PG506 because the coming days I´m busy with other things.
Working and measuring on the PG506 need all your attention (floating ground) so I must have time for it.
You gave me more than enough things to sort out that I can check, so when I know more I give a reply.

Furthermore thanks for your effort and next week hopefully I know more, René


Re: 468 Digital Storage scope

Michael W. Lynch
 

Dr. Zeller,

Do you have the Service manuals for this unit? If not, I would strongly advise you to cease working until you get the correct service manuals (at least get a digital copy). I have the paper manuals, which I prefer. I also have 3 of these scopes that I have repaired and the manual is essential to the process. These scopes are extremely complex and diagnosis or repair will be next to impossible without the manuals.

That being said, The analog section is almost identical to the 465B, so that helps. You can test for signals at or just prior to the deflection plates. The test points and wave forms are all shown in service manuals.

There is not any HV present on the deflection plates, as there is with the Cathode heater.

Good luck with your repairs.

--
Michael Lynch
Dardanelle, AR


Re: PG506 Repair - I had a Great Day today/

Michael W. Lynch
 

On Wed, Apr 21, 2021 at 03:51 AM, tek_547 wrote:

René,

Good day!

You have done a lot of work, way more that I have done. Thanks for the details, this eliminates some of the thing that could have effected your unit.

Balance of reply is INTERLEAVED below

When "I push the variable in" I see the "88" with the decimal point in the middle.
This is Good and Normal. Indicates that the LED are capable of function once the proper signals are restored.

I said before that only the HIGH led is continue working but that is not
correct. It is the LOW led that is all ways on so sorry about that.
ANSWER: Not a problem, that will likely be cured along with the display function.

But the 5V1 at the collector from Q70
is a bit low; about 4,75V The 5V from the power supply schematic 1 (lower left
corner) is 5,03V so this looks normal.
Is on yours PG506 the 5V also a bit low after Q70 ? Maybe this is important.
This Should not be a problem, I will check mine to confirm voltages at this point. I believe that they are using Q70 as a on/off switch for the display when in "Std. Amplitude Variable mode".

The parts that I changed is a long list so here we go:
U665, 666, 667 and 668 changed (no difference)
U670 and U671 changed (no difference)
U673 and U675 changed (no difference)
U615 changed (no difference)
U430 and U460 changed (no difference)
U470 changed (no difference)
U400 changed (no difference)
Furthermore are most of the transistors checked so that there are no shorts.
ANSWER: WOW! This is a HUGE list. Specifically on U400, have you checked for wave forms at the various pins of your "New" U400. If you have pins stuck High or Low (missing wave forms), then your problem is obviously before or after that IC. Check to see that you have wave forms at pins 1~6 and pins 8~13. Probe carefully to avoid shorting between pins. Pin #7 is Ground and Pin#14 is 5V Supply. All other pins will have some sort of pulse train if the instrument is working correctly (sans the display).

Did you confirm that the other remaining 156-0067-00 (741CN) op amps are all good? These would be U50, U200, U240,U330, U375 in addition to the two that you already changed. Most of these are in sockets, so they are not a major problem to change. I also added sockets for U200,U240,U255 and U480 at the time these were replaced. I cannot say for sure that U255 and U480 (opto-couplers) were bad, however I had the board out and the desoldering pump hot, so it was a simple task to remove them, add sockets and install new 4N27's.

Regarding transistors, I found two 151-0223-00 NPN (Q435 and Q535) that were bad on my unit and they were the final two pieces that restored the unit to operation. I have the luxury of a Type 576 Curve tracer for testing, but you can test these and see if they are bad or not by other methods. I replaced these with 2N3904 parts and they worked just fine. Confirm the 4V 1kHz square wave pulse signal at Pin #8 U400 then look for that same signal at R532, then on the base of Q535. Remove and check Q535. I suspect that you will find Q535 to be defective.

You made no mention of diodes, you would be wise to check all the diodes and confirm they are good. I found a couple of bad ones early on. Those were all 152-0141-02 (1N4152R) which had failed.

And also maybe interesting is the fact that T130 in the power supply is about
70°C when the STD AMP switch is activated. So not possible to you put your
finger on it.
When it is on FAST RISE or HIGH AMPL. the temperature is more normal (about
45°C).
Has your PG506 the same behaviour about the temp from T130?
ANSWER: I will need to check this out.and report back. I do not remember mine being hot.

So the few things I did not changed are;
The display board A4 (a bit clumsy to remove) and the two opto couplers U480
and U255 (do you have a substitute number for that type?)
ANSWER: 156-0399-00 Opto Couplers are 4N27. You can find these and many more useful cross references in the TEKTRONIX SEMICONDUCTOR Common Design Parts Catalog, Available at TEKWIKI
link: http://w140.com/Tektronix_Xref_sm.pdf

I think the problem is in the display section (board A4) or in the digital
voltmeter circuit (schematic 3) but maybe you have other suggestions.
ANSWER: I am thinking a bad diode or transistor.

I´m glad to hear what you think about and maybe I get it work normal after a
while, René
Anything that is not clear, please ask me to elaborate. Sometimes I am lacking in my explanations.

Sincerely,

--
Michael Lynch
Dardanelle, AR


Re: 492P signal amplitude error and error 58

Attilio
 

Thanks Bob,
I cannot locate the NEC mm765 RF amp or the uPC1764A in the 492P.
As soon as I get the spare, I try to replace the 1st LO YIG.

--Cheers
Attilio


560 Series Plugin Dimensional Drawings

David Holland
 

Hi,

Anyone happen to know if there are dimensional drawings for the 560 series
plugins floating about?

I'm thinking about taking a stab at modelling a 3D printed plugin
protector/container.

Yeah, obviously, I can pull out the ol' micrometer and measure one, but
being lazy, I thought I might ask if someone was aware of something and
save myself some effort.

Thanks & Cheers,

David


Re: 468 Digital Storage scope

Dr. Manfred K. Zeller
 

Can I measure the horizontal an the vertical signal direct on the tube
connection?
Direct on the two wires on each side.
The digital part is disconnected.
With a second Oszilloskop.
Or is a voltage in addition there - like on the heater filament?
Or there are other testpoints to see the horizontal and vertical signals?
Thanks a lot!


Re: PG506 Repair - I had a Great Day today/

tek_547
 

Hi Michael, thanx for your time and trying to help me with solving my problematic PG506.
When "I push the variable in" I see the "88" with the decimal point in the middle.
I said before that only the HIGH led is continue working but that is not correct. It is the LOW led that is allways on so sorry about that.
The output signal of the PG506 is functioning fully normal, and also "variable" is working correct. The problem is only the display. A bit erratic; sometimes steady and sometimes all segments are glowing when turning the variable.
So at your questions if the amplitude of the waveform respond to turning the "variable" knob or remain fixed at one level? and "Do the amplitudes generated in each switch position agree with the selected value of the switch across all positions?" I can say that these functions normal.

All the capacitors in the power supply and other boards of the PG506 are recapped, so power supply´s are normal. But the 5V1 at the collector from Q70 is a bit low; about 4,75V The 5V from the power supply schematic 1 (lower left corner) is 5,03V so this looks normal.
Is on yours PG506 the 5V also a bit low after Q70 ? Maybe this is important.

The parts that I changed is a long list so here we go:
U665, 666, 667 and 668 changed (no difference)
U670 and U671 changed (no difference)
U673 and U675 changed (no difference)
U615 changed (no difference)
U430 and U460 changed (no difference)
U470 changed (no difference)
U400 changed (no difference)
Furthermore are most of the transistors checked so that there are no shorts.
And also maybe interesting is the fact that T130 in the power supply is about 70°C when the STD AMP switch is activated. So not possible to you put your finger on it.
When it is on FAST RISE or HIGH AMPL. the temperature is more normal (about 45°C).
Has your PG506 the same behaviour about the temp from T130?

So the few things I did not changed are;
The display board A4 (a bit clumsy to remove) and the two opto couplers U480 and U255 (do you have a substitute number for that type?)
I think the problem is in the display section (board A4) or in the digital voltmeter circuit (schematic 3) but maybe you have other suggestions.

I´m glad to hear what you think about and maybe I get it work normal after a while, René


Re: CRT, unknown

Mark Vincent
 

Bert,

What are the numbers of the Dumont crts? The numbers would indicate if I can use them. Thanks.

I do have a 3ACP11. I would like to know where the 3ACPx/x types were used in.

Mark


Re: Transistor for 1730 Waveform monitor

greenboxmaven
 

Tekwiki was the first place I went to, followed by Sphere.

    Bruce Gentry, KA2IVY

On 4/20/21 17:17, adesilva_1999 via groups.io wrote:
You might find in one of these:

https://w140.com/tekwiki/wiki/Reference_material




Re: 468 Digital Storage scope

-
 

I know that it's counter intuitive but have you tried adjusted the
horizontal position to both the left and right extremes? I have seen
scopes where the position was adjusted too far to the right (or the left)
and the spot would be near the RH edge of the display and adjusting the
position to the right would only make it it move left! But only a limited
amount. Apparently the beam was so far to the right that it was off the
display but it reflected off of the glass envelope or one of the internal
elements and reflected back onto the display!

If that's not the problem then check the power supplies before you do
anything else.

On Tue, Apr 20, 2021 at 5:34 PM Dr. Manfred K. Zeller via groups.io
<drmanfredzeller=googlemail.com@groups.io> wrote:

It is now like it is / pressing the beam finder in the xy mode on the time
base I have now a point on the right side of the screen.
Otherwise the screen is empty.
What do you recommand doing the next step?
Thanks a lot!
Manfred






Re: 468 Digital Storage scope

Michael W. Lynch
 

On Tue, Apr 20, 2021 at 04:34 PM, Dr. Manfred K. Zeller wrote:


It is now like it is / pressing the beam finder in the xy mode on the time
base I have now a point on the right side of the screen.
Otherwise the screen is empty.
What do you recommand doing the next step?
Are you operating the scope in the Non-Store or Storage Mode? You should be working in NON-Store mode until you confirm that the analog portion is working correctly.

--
Michael Lynch
Dardanelle, AR


Re: 468 Digital Storage scope

Mark Vincent
 

What I said about the transformer being bad was wrong. The multiplier is suspect. My mistake. The multipliers will go bad causing your problem. I apologize for any confusion.

Mark


Re: 468 Digital Storage scope

Mark Vincent
 

Raymond and Dr. Zeller,

The resistor I mentioned is commonly there in many models. I know not all have a heater resistor. I do not have the schematic in front of me. What I said was an assumption of a resistor being there. What has been suggested as a likely cause is the high voltage transformer being bad. What is said about measuring the heater voltage is correct. Use a good VOM or DMM that will respond to the frequency of the oscillator circuit and measure across the heater pins, 1 and 14 of the base. It should be 6,3VAC. Keep your fingers away from the tips when the scope is on. You can measure the resistance with the socket removed to confirm a complete circuit, not open. There will be a up to a couple of ohms of resistance due to the winding resistance. Read and do what the other posters have said. They will be spot on about your problem.

Mark


Re: 468 Digital Storage scope

Tom Lee
 

Yes, electrostatically-deflected crts have to operate the plates near ground potential to prevent distortions due to other objects near the tube (such as your finger resting on the screen). That forces the cathode end to be kV below ground. And, since you can’t have too great a voltage difference between heater and cathode (to avoid breakdown), the heater has to be at about the same potential as the cathode.

TV crts are magnetically deflected, so their cathodes are near ground potential, while the anodes are very positive. Those with experience only with TV crt circuits often get, er, surprised by scope crt circuits. Glad you survived your encounter!

— Cheers,
Tom

Sent from my iThing, so please forgive typos and brevity.

On Apr 20, 2021, at 2:54 PM, Dr. Manfred K. Zeller via groups.io <drmanfredzeller=googlemail.com@groups.io> wrote:

Thank you Raymond for helping me - I did not know that the heater is
connected to 2450 Volt.
Thank you very much for your help!
Manfred





Re: Transistor for 1730 Waveform monitor

Tom Lee
 

If you are located anywhere near Silicon Valley, I can just hand you a TIP31C. I have many.

—Cheers,
Tom

Sent from my iThing, so please forgive typos and brevity.

On Apr 20, 2021, at 1:28 PM, greenboxmaven via groups.io <ka2ivy=verizon.net@groups.io> wrote:

I have a 1730 waveform monitor that has fried the transistor that drives the high voltage transformer. A malfunction in the CRT bias circuit caused the beam current to go too high and fry the transistor. The Tektronix part number is 151-0476-00. Does anyone know the generic equivalent?� I know I can choose one that will work, but using the closest replacement would be best and keep me from chasing two troubles at once. Has anyone compiled a list of replacements for the factory part numbers?

���� Bruce Gentry KA2IVY







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