Derek92994's 700 Ser II White Oak conversion

[J!m]

You test them with a cigarette?!? That’s a new one on me.

Subscribed.

 

[derek92994]

Getting better at that..

Walk in the Park, got a good mentor

 

[laatsch55]

Well thanks .

 

[derek92994]

1st output shorted E- to C+ and E+ to C-
Lucky I have 1 spare output left.

 

[derek92994]

Couple of thoughts. Remember when the D board failed? Quite a few times on power up the meters would peg. Is it possible outputs were weakened due to this, and/or heat from removing and reinstalling? Could there be another problem causing outputs to blow or is it common just for them to die randomly?

 

[derek92994]

Replace bad output and reinstall I am guessing

 

[laatsch55]

Darc, there could be some wounded ones, but you'll never know. I have replaced ALL OUTPUTS after a nuklar failure like that, and then I've just replaced the one, if you had a later generation of backplanes it would be a piece of cake...I'd replace the one and move on. Check all emitter resistors and the small 1/4 watt resistors towards the bottom. Check the bias tyranny too...

 

[laatsch55]

It's not common to die randomly...

 

[derek92994]

Ok will put outputs back in, the bias transistor, emitter resistors and 1/4 resistors check with outputs installed?

 

[laatsch55]

No, do it before..

 

[derek92994]

They all check out good

 

[laatsch55]

You're good to go Darc!!

 

[derek92994]

Ok will install outputs, any another checks to do between this and dim bulb/variac procedure?
I know we will have to check dc offset and bias

 

[laatsch55]

Nope...

 

[laatsch55]

Darc, post a pic of the used sil-pads would ya??

 

[derek92994]

Im using new ones but these are the old

 

[derek92994]

The 3rd sil pad top row, was some dirt on there, its not a hole

 

[derek92994]

Another thought, if the (old) batteries on my battery system sag slightly on wopl power up, could this be causing outputs to blow?

 

[laatsch55]

No, just sags the power supply, on a no load situation, not a problem. Don't tighten them as much this time. Take the slack out and a wee bit further..

 

[derek92994]

Outputs back in, soldering time.