Schaffner NSG 1025 repair [Updated]

[implor]

I got a Schaffner NSG 1025 off eBay. It’s sold as not working and before turning it on I opened it up and found a snake.


I'm looking for a manual or service documentation if you have it.


Symptom:
output voltage on display vary up an down. After a while it will settle.

[implor]

Reverse engineering attempt:



Pulses are generated mainly by classic 555 timers. After probing around it looks like very noisy rails. Would explain symptom also. Next step is power supply board.
Blue wires might look home made but solder joints are text book IPC style so i'm 99% sure this is from factory. Also they go isolated "extra" footprints and images of a NSG 1025 on youtube have same components there (resistor and diod).

[implor]

As suspected. Leaky caps.
New ones are on order from digikey. Will replace every one so I never need to care again. This unit has datecode 1991 so they have lasted for 35 years.

Caps on supplyboard:
2x 1000uF 10V d10xL20
2x 220uF 35V d8xL20
1x 470uF 10V d8xL15
2x 47uF 25V d6.3xL12
1x 4.7uF 50V d5xL12
1x 68uF 400V d25xL25 (lead space 10mm)

[hulchm9ib]

Hi there,

Nice piece of kit I have one of those which also needs fixing so I'm closely following your work up

Kind Regards
Ian.