The B-2 Restoration

[rottalpha]

Also, if you disconnect the blue shielded wire from the input of the vumeter board, do you still see the one channel acting funky? I guess I should have asked you that first.....

 

[bobdod]

I had the PNP pair fail too and as a rule I replace them all for all my restorations. It bit me in the arse a few times for living them in. Anything with black legs has to go.

This. I had a funky meter and after testing all of the transistors on the board and not finding an obvious issue I just replaced them all. Problem solved.

 

[rottalpha]

This. I had a funky meter and after testing all of the transistors on the board and not finding an obvious issue I just replaced them all. Problem solved.

yes because they require a little bit of heat to start acting out. Freeze spray would help you find the exact ones, but it is a futile exercise. All of those transistors with black legs will fail sooner or later and it is a pain to go back and rework that board. I carpet replace them ...I am sure that @Sparkplug will share his thoughts politely once he sees this but I know what he really thinks

 

[Nashou66]

Yep, black leg creep is a tell tale sign to toss it. Been there done that .

Athanasios

 

[Sparkplug]

yes because they require a little bit of heat to start acting out. Freeze spray would help you find the exact ones, but it is a futile exercise. All of those transistors with black legs will fail sooner or later and it is a pain to go back and rework that board. I carpet replace them ...I am sure that @Sparkplug will share his thoughts politely once he sees this but I know what he really thinks

You know me too well …
I should trademark that term … carpet-change … LOL

 

[Arye]

Yes I discoconected the blue shielded wire from the input of the vumeter board, and the prolem is still there, I'll start replacing all the black leged trans, and maby more, this weekend.
Hope it will fix it.
Thanks to all suggestion, I highly appreciate that, this is a great forum and members to learn from

 

[rottalpha]

Yes I discoconected the blue shielded wire from the input of the vumeter board, and the prolem is still there, I'll start replacing all the black leged trans, and maby more, this weekend.
Hope it will fix it.
Thanks to all suggestion, I highly appreciate that, this is a great forum and members to learn from

don't forget the two tantalum caps. Replace those first and test again. You should be able to replace those fairly quickly without the need to fully remove the board.

good luck!

 

[Arye]

Finally success It turn out that I needed to replace all transistors, except of the power saction.

 

[Arye]

Q