Siemens D1052 oscilloscope (Gould DSO 4096).

[Noopy2014]

That's only a square wave your scopes are showing but that looks good. The edges are quite sharp. Everything ok so far. Obviously no bigger problems.

[Roberts981]

Originally Posted by dave cox

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.

dc

Originally Posted by Noopy2014

That's only a square wave your scopes are showing but that looks good. The edges are quite sharp. Everything ok so far. Obviously no bigger problems.

Well I can hear chirping from psu when it is on, I guess it is from struggling transformer.
Right now this forum made me interested in a quest on finding the easiest method to locate where this unit is drawing that amount of power...

So as I do not want to torture it, oscilloscope is put to sleep until I find resources with which I can locate shorts...

[Noopy2014]

Perhaps there is no problem...
A power consumption of 2xxW is ok.
Traces look good.
Chirping can be caused by a not perfect transformer or something loose in the magnetic field.

[Roberts981]

Originally Posted by Noopy2014

Perhaps there is no problem...
A power consumption of 2xxW is ok.
Traces look good.
Chirping can be caused by a not perfect transformer or something loose in the magnetic field.

Yes it very might be, I talked today to also experienced electronics repair guy, and he told me almost the same thing, plus he told me about many causes of chirping...

I really did not find any module which draw significantly more current then the rest of modules...

Only thing that struggles me is about voltage of -5 rail...

Conclusion would be possible by someone measuring Gould 409X overall power consumption as the unit now with spot on -5v rail draws 20watts more power then classified max for 4070 psu...

[Noopy2014]

Measuring the power consumption of a 40xx isn't an easy task:
I have seen peak currents of 43A since there is a huge capacitor behind the rectifier.

[Noopy2014]

As it happens I have a D1052...
After performing it's selftest it consumes 249W (428VA!).
Perhaps the 409x need some more power than the 407x...

[Roberts981]

Originally Posted by Noopy2014

As it happens I have a D1052...
After performing it's selftest it consumes 249W (428VA!).
Perhaps the 409x need some more power than the 407x...

Wow, today I was at work blitz, as the town hall put an end to work from home...
I did reed your post in a hurry about your unit, but it did not hit me today they are the same...
I guess your -5v rail is adjusted the same as mine was before (at around -4.7v).
Anyway thank you very much about measurements made, because that would indicate this question as true and which might conclude this topic as resolved

[Roberts981]

Here is the output coming from yamaha v375 receiver, could not find option to magnify y axis on siemens d1052, so output is 5times lower...seems very correct...
That is with somewhat low volume on 8 ohm resistor.

[Noopy2014]

You are right, there is no y-magnify but the D1052 can go down to 2mV/div. That should be good enough.

[Roberts981]

https://www.google.com/url?client=in...P3E5ad2HGQ_Hc2
Above topic is closed so I have to open a new one.

It served me a short time. Few turn ons and puff magic smoke came again.
This time we could identify blown parts.

1. 3.15A FUSE on PSU casing had blown and than we replaced it.

After that next happened:
2. 100 ohm RESISTOR R34 blew up.
3.Q11 (BU810) has short between Emitter to Collector.

Should I look for any further parts causing this behavior before turning it on again?

CHEERS.

[Cobaltblue]

The original thread opened and new post merged you can always request closed threads to be re-opened using the red triangle.

Cheers

Mike T

[Roberts981]

I need this supply fixed as soon as possible. Any thoughts on burning r34?

Here goes pdf on supply rail:
https://www.vintage-radio.net/forum/...3&d=1399804554

[mole42uk]

This power supply is quite a beast. If you search and find my old thread about repairing the supply you will find lots of clues.
One thing to remember is that the switch mode side is in two parts, both of which need to work properly before you'll get anyhting sensible out of it. I have two working ones, both of which have completely new capacitors and probably several other parts, it's been a long time. My Gould DSO is a long project.....

[Roberts981]

Thanks and I really mean it...

[Roberts981]

Originally Posted by mole42uk

This power supply is quite a beast. If you search and find my old thread about repairing the supply you will find lots of clues.
One thing to remember is that the switch mode side is in two parts, both of which need to work properly before you'll get anyhting sensible out of it. I have two working ones, both of which have completely new capacitors and probably several other parts, it's been a long time. My Gould DSO is a long project.....

Following old thread revealed shorted diodes d17 and d18, new q11, and new r34.
We still got burned something inside.
We had no more energy that day to look inside again.
Are we missing something.