x2turbo
Well-Known Member
I'm in the process of restoring a 2238B. I'm replacing all the electrolytics to lengthen it's life and taking the shotgun approach of replacing all the transistors and zener diodes on the amp board because I could only get it to 28v when 35v is spec.
The amp board has definitely been worked on before and I have a couple of questions for those that know much more than me.
C164 is spec'd at 16v 220uf and I found a 16v 10uf installed. I returned it to spec.
Is this the general rule of thumb when one finds discrepancies? To put it back to spec? Or should I maintain the same cap since other parts that I'm not replacing may have been the reason behind the change.
There are a couple of caps installed on the bottom side of the board and by the amount of flux I'd say they weren't original.
First there is a 50v 47uf cap. It's connected between pin J739 and zener Q746.
A 200v 473m cap between pins J706 and J708
A resistor connecting the poles of the varistors, STV-3H (Q), Q741 and Q742 respectively. Note I'm not replacing these since I couldn't locate a replacement.
and finally a 100pf ceramic between pins J722 and J728
Any thoughts on why these may be here?
Thanks
The amp board has definitely been worked on before and I have a couple of questions for those that know much more than me.
C164 is spec'd at 16v 220uf and I found a 16v 10uf installed. I returned it to spec.
Is this the general rule of thumb when one finds discrepancies? To put it back to spec? Or should I maintain the same cap since other parts that I'm not replacing may have been the reason behind the change.
There are a couple of caps installed on the bottom side of the board and by the amount of flux I'd say they weren't original.
First there is a 50v 47uf cap. It's connected between pin J739 and zener Q746.
A 200v 473m cap between pins J706 and J708
A resistor connecting the poles of the varistors, STV-3H (Q), Q741 and Q742 respectively. Note I'm not replacing these since I couldn't locate a replacement.
and finally a 100pf ceramic between pins J722 and J728
Any thoughts on why these may be here?
Thanks
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