Author Topic: Smoke und fire after switching on old electronics TEK DSA 602 (Read 11491 times)

bd139 · « **Reply #25 on:** August 11, 2017, 08:18:02 pm »

Yep RIFA X2. Well know flame throwers. Hit google images and search for "RIFA X2 explode".

Desolder it, clean the board up with IPA carefully and damage assess. If nothing is damaged, bring the supply up without it still installed and see if it works. That badly burned one is a write off.

I'd advise getting on the cleaning pretty quick as that goop sets like concrete after a couple of weeks.

Physikfan · « **Reply #26 on:** August 11, 2017, 08:46:22 pm »

Hi bd139

Please what do you mean with IPA, iso-propyl-alcohol?

Regards

Physicfan

bd139 · « **Reply #27 on:** August 11, 2017, 08:56:44 pm »

Yes that's it

Johnny10 · « **Reply #28 on:** August 12, 2017, 08:27:40 pm »

What is the proactive treatment for this issue?

I have two of these on my bench that I fire up and use at least twice a week.

bitseeker · « **Reply #29 on:** August 12, 2017, 08:44:00 pm »

Proactive treatment is to replace them if they're old. The first visible signs of impending doom are small cracks developing in the transparent/translucent outer casing.

bd139 · « **Reply #30 on:** August 12, 2017, 09:25:25 pm »

That's all you need to do. The cheap Chinese X2 rated ones are fine as replacements.

Physikfan · « **Reply #31 on:** August 13, 2017, 02:02:57 pm »

Images of parts of the DSA602:

Defective component removed

Second same component still intact

Small filters

Images of parts of the DSA602A:

Second same component still intact

Small filters

I am looking forward to your comments

Johnny10 · « **Reply #32 on:** August 13, 2017, 02:11:36 pm »

Not sure what the pictures are showing.. two different boards or boards from DSA602 and DSA602A?

Physikfan · « **Reply #33 on:** August 13, 2017, 03:24:58 pm »

Hello Johnny10

The pictures are showing views of boards from DSA602 (3) and DSA602A (2).

The pictures 1,2 and 3 of my last post show different views of the first power supply board of the DSA602.
The pictures 4 and 5 of my last post show the analog views of the same power supply board of the DSA602A.

For me it is remarkable that the same capacitors RIFA 0.6 uF X and RIFA 0.6 uF X2, both on the upper left of the boards, and also ONLY these, are fumed in these different oscilloscopes DSA 602 and DSA 602A, randomly?

I must also admit that this incident was my first encounter with this type of interference suppression capacitors.

Regards

Physikfan

Johnny10 · « **Reply #34 on:** August 13, 2017, 05:24:28 pm »

I guess next week I will have to open these two beasts up and do some work.
Phew and they are beasts !

bd139 · « **Reply #35 on:** August 13, 2017, 06:29:56 pm »

Check your HP kit as well. It's usually full of the flame throwing bastards!

bitseeker · « **Reply #36 on:** August 14, 2017, 05:22:17 am »

Quote from: Physikfan on August 13, 2017, 03:24:58 pm

For me it is remarkable that the same capacitors RIFA 0.6 uF X and RIFA 0.6 uF X2, both on the upper left of the boards, and also ONLY these, are fumed in these different oscilloscopes DSA 602 and DSA 602A, randomly?

Unfortunately, these RIFA caps are infamous for blowing up. The only random thing about them is which one will burst into flames next. Change them all before applying power again. Those small 0.015 look like RIFAs, too.

Physikfan · « **Reply #37 on:** August 14, 2017, 07:54:08 am »

Hi Johnny10

If you will do the job next week
"I guess next week I will have to open these two beasts up and do some work."
please, could you post exactly the capacitors which you will use for the replacement.

You are planning to use new Y2 capacitors (two 0.6uF caps and two 0.015uF caps) for each of your DSA602´s of a certain brand or only high quality capacitors for high voltages around 1000V DC?

By the way, nice lab!

Regards

Physikfan

Johnny10 · « **Reply #38 on:** August 14, 2017, 11:09:17 pm »

I am going to start looking for caps this week.
I went to my local surplus store but no x2 or Y caps in his stock.

Will have to look at suppliers.
So far they don't seem too expensive just that I am going to have to order through mail.
Will keep you informed.

Physikfan · « **Reply #39 on:** August 18, 2017, 10:56:39 am »

Hi Johnny10 and all DSA602 and DSA602A owners

Please which DSA602 and DSA602A owner has already had its device open and
can tell me something about the wiring of this board just next to the power supply?

It is about the two-pole white plug, the third from the left bottom, with the two cables red and brown.
In my DSA602A it is present, in my DSA602 it is missing.

I wonder now, due to a lack of circuit diagram, whether it has to do with the power supply of the floppy disk drive in the DSA602A.
The DSA602A has one, the DSA602 has none.

Best regards

Physikfan

Old Don · « **Reply #40 on:** August 18, 2017, 11:14:56 am »

Quote from: Physikfan on August 11, 2017, 08:46:22 pm

Hi bd139

Please what do you mean with IPA, iso-propyl-alcohol?

Regards

Physicfan

FYI, one other shorthand ---> DNA = denatured alcohol and not the stuff you provide to Ancestry.

kleblanc · « **Reply #41 on:** August 18, 2017, 05:16:56 pm »

No pictures of it but,

A customer was having an issue with a temp controller so they changed it out and wanted me to get calibration data on it. So they hand me a 120vac cut cord the controller and a picture of how it was wired. In the picture there was a black/white wire and everything thing else was red wiring.

I didn't even think and wired the 120vac black and white wires to the same wires as in the picture. Well, that was the normally closed relay and once I plugged into the outlet I tripped the breaker. Needless to say, the unit issues were put to rest since the unit was designed for 24 vdc and 120vac fried everything in it to power on.

Morale of the incident is when a customer tries to help, it never seems to end up good.

Johnny10 · « **Reply #42 on:** August 20, 2017, 07:22:38 pm »

OK
So I opened the DSA602A !! Yikes that thing is heavy.

Sent Pic of control rectifier board on DSA602A

How did you get to RIFA chips?
Through back panel?

Physikfan · « **Reply #43 on:** August 20, 2017, 07:55:35 pm »

Hello Johnny10

To remove the power supply module from the DSA602A
the first step is to unscrew 14 screws at the back of the DSA602.
Before you completely remove this power supply module from the DSA602A, the second step is to disconnect the cables that you have shown in your image.

Your second DSA oscilloscope is also a DSA602A?

Regards

Physikfan

Johnny10 · « **Reply #44 on:** August 20, 2017, 08:03:27 pm »

Second scope is DSA 602 no floppy drive

Physikfan · « **Reply #45 on:** August 20, 2017, 08:40:41 pm »

Hi Johnny10

Here are links containing access to DSA manuals:

http://w140.com/tekwiki/wiki/DSA600
bee.mif.pg.gda.pl/ciasteczkowypotwor/Tek/DSA600-service.pdf

You have posted this nice picture of the DSA602A.
Please could you post also the analog picture of the DSA602?

Regards

Physikfan

Johnny10 · « **Reply #46 on:** August 20, 2017, 08:50:48 pm »

OK I pulled out power supply.

Posted pics of both DSA units in previous post.... they look identical to me and the date markers are both from 1991.

Physikfan · « **Reply #47 on:** September 11, 2017, 04:11:07 pm »

Hello Johnny10

Have you finished the replacement of the X2 capacitors?
What kind of capacitors have you used finally?

Regards

Physikfan

Johnny10 · « **Reply #48 on:** September 11, 2017, 05:32:14 pm »

No

I was working on getting the front keys on my datron 4000a working.
From another thread you can see that was all I needed to finish.
Success on that front.

Last 4 days prepping for Hurricane Irma.

I am on the East Coast... made it alright.

Next is DSA602A

Did you also change Y caps?

Old Don · « **Reply #49 on:** September 15, 2017, 01:22:42 am »

Back in the early days of personal computers (S-100 era) I acquired several very expensive 64K dynamic RAM boards since they were defective. Turns out the factory silk screened the component polarity incorrectly for the main tantalum cap on the minus voltage pwr supply. Plus symbol pointed to negative pwr rail and "-" pointed to ground.

They then went and stuffed the boards to match the indicated polarity. After a bit of usage they all when POOF! Magic smoke went out and the boards were sold for scrap. I installed new caps with the + lead to ground and "-" lead to the minus pwr rail and they all worked!


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Author Topic: Smoke und fire after switching on old electronics TEK DSA 602 (Read 11491 times)

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