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Old 7th Dec 2020, 9:03 am   #1
Roberts981
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Smile Siemens D1052 oscilloscope (Gould DSO 4096).

Hello this is my first post on this forum, hope someone will help on adjusting this power supply.

Does anyone have some information what are these pots for.

I do have a main pot which adjusts +16v, +-5v rails together, but these two are intriguing as i don't want to mess with them as I have learn that main pot is very sensitive. Unless they are for +-5v...

Unit seems happy now, but I have to finish it as 17.7 volts on 16 volts rail seems a bit on the high side.

So far I have cleaned a 2.4v NICD battery leakage across board with Hydrochloric acid, baking soda for neutralization, and finished with ethyl alcohol. Board does look like new now. Washed with water in between steps.
Replaced all Rifa capacitors with x and y class pp.
Replaced output capacitors 2x1000uf35v + (1x470uF 25v - this one was manufactured with around double the capacity so I have replaced it with 1000uf one).
Replaced both buk455-200a with equivalents *one was shorting out because of leaking capacitors
Replaced BIOS battery with NIMH one.
Had changed one small resistor as it seemed like it was acting up 0.5w 270k.
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Old 7th Dec 2020, 9:55 am   #2
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Default Re: Siemens D1052 oscilloscope (Gould DSO 4096).

Well, you need to read the manual and find out what the tolerance on the 16V rail is. I agree with you that 17.7V sounds most likely to be well out of spec.

So your first job is to get a copy of the manual. I did a quick search on the net and only turned up a very dodgy looking site, which my antivirus blocked. It may be that someone on here has a copy they can share with you.

Once you have the manual, I would sort out the power rail, and then go through the entire calibration procedure and any other tests to see what state the instrument is now in. And obviously fixing faults as they appear.

As a general comment........any board that has had highly conductive chemicals across it may be in a dodgy state, with conductive paths which will provide leakage in unexpected places. A lot will now depend on how well you washed the board. Did you used de-ionised water to wash it with? If not, you may well have left traces of salts behind, which can cause problems, which in my experience get worse as the relative humidity rises.


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Old 7th Dec 2020, 9:19 pm   #3
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Default Re: Siemens D1052 oscilloscope (Gould DSO 4096).

Only tap water...

I know about that site with virus, will try that again with caution...
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Old 7th Dec 2020, 10:56 pm   #4
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Default Re: Siemens D1052 oscilloscope (Gould DSO 4096).

No service manual is there online for this unit...
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Old 8th Dec 2020, 10:51 am   #5
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Default Re: Siemens D1052 oscilloscope (Gould DSO 4096).

Hi Roberts,
Siemens -and Gould too- docs are very problematic, practically nothing is on the web...
Hopfelly thes helps for you_Im not registered: http://bookclubforum.club/books.php?...e+manual+forum
and these one; http://nvhrbiblio.nl/biblio/boek/Hic...illoscopes.pdf
regards, K.

Last edited by karesz*; 8th Dec 2020 at 11:07 am.
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Old 8th Dec 2020, 2:44 pm   #6
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Default Re: Siemens D1052 oscilloscope (Gould DSO 4096).

Quote:
Originally Posted by karesz* View Post
Hi Roberts,
Siemens -and Gould too- docs are very problematic, practically nothing is on the web...
Hopfelly thes helps for you_Im not registered: http://bookclubforum.club/books.php?...e+manual+forum
and these one; http://nvhrbiblio.nl/biblio/boek/Hic...illoscopes.pdf
regards, K.
And when I click on the first link, its the same website that I had a problem with - and which my antivirus says "get me out of here"!

The second link looks a useful reference for digital storage scopes in general. But in this case, very specific information is needed on the Gould 4096 which will only be found in its service manual.

Its a bit of a mystery as to why Gould scopes' manuals should be hard to find. We had several models at work back in the 1980s. This site shows that "Gould" became "Gould Advance" at some point, and its unclear whether they are still in business in some form or other. Sometimes manufacturers still hold data for old products. The radio museum site does have its own forum with a more European focus - it might be asking there for help. That site does have entries for other Gould products (e.g. 4040 DSO and 4041 - but not 4096).


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Old 8th Dec 2020, 2:48 pm   #7
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Default Re: Siemens D1052 oscilloscope (Gould DSO 4096).

And looking at this brief data on the 4096, it looks very expensive, and high end (200MHz bandwidth) for the end of the 1980s. So it may well be that very few of them were made and sold, which would explain why the manuals simply aren't out there.

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Old 8th Dec 2020, 10:08 pm   #8
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Default Re: Siemens D1052 oscilloscope (Gould DSO 4096).

The first site is link to a well known scam.
Just google for "but it requires cc"

https://www.reddit.com/r/Scams/comme...ill_it_in_its/
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Old 10th Dec 2020, 5:02 pm   #9
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Smile Re: Siemens D1052 oscilloscope (Gould DSO 4096).

No service manual whatsoever.

Well I have just replaced some more caps that were suspicious. Just haven't touched big Philips blue ones as they read very good on an ESR meter.

Now about the differences in voltages. It does look that I have found the culprit which is eating the voltage and it looks like it is somewhere between the -5V rail and ground. Resistance between -5v output on PSU and ground of *0V* is 10.7 ohms and that is on one of the plug in boards, but manually finding which component on that board is causing this, was not possible for me and my budget hand held digital multi-meter.

What are mine options now? I do own usable thermal camera and regulated power supply with only positive voltage output. I'm all new to this, but enjoy finding faults, so please help if you can...
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Old 10th Dec 2020, 10:02 pm   #10
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Default Re: Siemens D1052 oscilloscope (Gould DSO 4096).

I have been rebuilding a Gould 4074 DSO which seems similar. The power supply in my instrument was a problem but that is now okay. If yours is similar, there are several plug-in boards which have separate the functions between them and it might be possible to isolate a power fault to one board.

One problem with my ‘scope was that a number of tantalum capacitors had gone out of spec, one or two had exploded. This inevitably leads to problems with the supply rails. There were also a couple of SMD resistors that had gone o/c.

The downside is that I’ve been working on getting this oscilloscope functional and reliable for five or six years. And I have the bulk of two examples to compare parts from.
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Old 10th Dec 2020, 11:36 pm   #11
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Default Re: Siemens D1052 oscilloscope (Gould DSO 4096).

Quote:
The downside is that I’ve been working on getting this oscilloscope functional and reliable for five or six years.
I'm sorry to be tbe bearer of bad news. From personal experience of Gould products when they were new, or just a few years old (back in the 1980s), they were so unreliable that the bit of Racal I worked for then decided to stop buying their products. I vaguely recall the 4074 was one of the products we had - a 4 channel scope if I recall correctly, and much in demand in the lab, but often to be found "away for repairs"!


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Old 11th Dec 2020, 7:10 am   #12
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Default Re: Siemens D1052 oscilloscope (Gould DSO 4096).

Quote:
Originally Posted by mole42uk View Post
One problem with my ‘scope was that a number of tantalum capacitors had gone out of spec, one or two had exploded. This inevitably leads to problems with the supply rails. There were also a couple of SMD resistors that had gone o/c.
.
My experiance is similar they can go bad, but they are everywhere on the boards.

Is there a way to find faulty ones especially tantalum ones?

I still can not find one very small 35v 10uf tantalum that have exploded (I have found his bits all over the unit and a piece of ferrite bead.
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Old 11th Dec 2020, 1:16 pm   #13
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Default Re: Siemens D1052 oscilloscope (Gould DSO 4096).

I know of 2 ways of figuring out where the (dc) current is going on a complex board, in a non intrusive way :

(1) a sensitive HALL-EFFECT probe that can measure the current flow/direction in a trace from its magnetic field. I don't have one so I have no advice to offer!
(2) a very sensitive voltmeter that can measure the voltage drop across a few inches of PCB trace. I have used a 6 digit voltmeter meter which proved usable but slow & tricky.

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Old 13th Dec 2020, 12:54 am   #14
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Default Re: Siemens D1052 oscilloscope (Gould DSO 4096).

I will post updates in a few days, as the shops for electronic components are not working because of covid situation....
I have made a list to buy and replace all electrostatics on these plugin boards.
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Old 15th Dec 2020, 5:44 pm   #15
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Default Re: Siemens D1052 oscilloscope (Gould DSO 4096).

I guess that the the board is working fine, as it is drawing only 0,46 amperes that is with (10.7 ohms on -5v rail)...
I have just finished replacing many axial capacitors that had high vloss just in case.
The unit manages to calibrate itself fine but I do have one major concern.

-5v line is still low.*so i have to adjust main pot line for -5v to reach its nominal values...
That gives me 18 volts on 16v line
Now I did measure transistor Q1 even after replacment on psu, having a hard time, overheating up to 100 degrees Celsius with no load and 70 degrees Celsius with all loads attached.
It was on "Q1" bf393 which is now replaced with mpsa42.
Now Gould 4072-4074 psu units have if not the same circuits.

So please can someone who has the 4070s manual tell me what does it say about this Q1 NPN transistor. Guideline for what to look for would be also very appreciated.
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Old 16th Dec 2020, 12:45 pm   #16
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Default Re: Siemens D1052 oscilloscope (Gould DSO 4096).

Today I will try this fix even though I tested both of these capacitors on Chinese gm328 esr meter and they resulted in perfect working order.
https://www.vintage-radio.net/forum/...5&postcount=36
This post corresponds to exactly what is happening to my scope...
I will post results after caps change...
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Old 16th Dec 2020, 5:00 pm   #17
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Cool Re: Siemens D1052 oscilloscope (Gould DSO 4096).

Quote:
Originally Posted by Roberts981 View Post
Now I did measure transistor Q1 even after replacment on psu, having a hard time, overheating up to 100 degrees Celsius with no load and 70 degrees Celsius with all loads attached.
It was on "Q1" bf393 which is now replaced with mpsa42.
Now Gould 4072-4074 psu units have if not the same circuits.

So please can someone who has the 4070s manual tell me what does it say about this Q1 NPN transistor. Guideline for what to look for would be also very appreciated.
Q1 is the transistor of a linear regulator supplying the CS3524 switching regulator. It has to cut ~70V while conducting ~7mA (18mA peak while switching). That's quite a lot. BF393 is right. MPSA42 should work too.
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Old 16th Dec 2020, 7:28 pm   #18
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Default Re: Siemens D1052 oscilloscope (Gould DSO 4096).

Thanks Noopy, will look to it right after this problem is fixed...

It might be I made some progress but not by changing these big blue caps for sure...

What I noticed after caps replacement was high voltage arcing noise in the psu...
(I forgot to connect noisy fan and that enabled me to hear arcing)

Last edited by Roberts981; 16th Dec 2020 at 7:35 pm.
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Old 17th Dec 2020, 7:01 pm   #19
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Question Re: Siemens D1052 oscilloscope (Gould DSO 4096).

So arcing is gone, it was on p7 and p8 connection points *see picture*...

But I still have some big concern about overheating transistor Q1 which feeds CS3524...Any thoughts what to look for? There is still a big difference on +-5v rail...
I read somewhere other units have way smaller differences...
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Old 17th Dec 2020, 7:22 pm   #20
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Default Re: Siemens D1052 oscilloscope (Gould DSO 4096).

Hm...
You can check C6. If it´s very leaky perhaps it draws enough current to overheat Q1.

I assume the problem with +/-5V should be found on the secondary side. That should be no problem for Q1.
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