• Please note that Audiokarma will be offline briefly for updates early on Monday morning, September 28th.

zenith PP 6bq5 console amp

I think I figured out what was going on or at least part of it. This thing was wired from the factory so the ground leg was switched. So the amp was grounding through the interconnects between it and my preamp and it created a dead short when I swapped polarity. I put on a new line cord with a polarized plug and rewired the switch into the hot side, hopefully that takes care of it. Now Im just waiting on my power supply caps to come and some other odd and ends. I spent a while last night trying to polish the top of the chassis and now im going to look for a nice piece of wood to make some trim out of. Theres a 100uf 25v cap that has three leads on it that goes from two pins the 5u4 to ground, how should I go about replcing this one ?
 
Anyone see one of those caps with the three leads? Is there a special name for it or something I could look for? Is this cap even a critical part of the power supply.
 
How about a picture. I can seem to pick it out of the schematic. Sorry for the delay. For that matter I don't even see a 100uF cap at all.
 
Is this 100/100uF cap in addition to the 70/80uF that we talked about earlier? I only see one can on the top of your amp. Maybe someone replaced the 70/80 with 100/100uF?
 
I only see one red wire going from that can to the 5U4 (presumably the 40uF pin). So I'm guessing the can is still the 40/70/80uF as it has 3 terminals (red, orange, white leads) and ground at the can tabs. Hopefully he'll clarify.
 
Thats also what I was wondering. If so we can see which side is ground. Then it must be a multi section 100uf? Should be 450V cap then.
 
OK, the posts crossed. Does that black cap have 3 wires from it or just one at each end with one end connected to ground tab and two wires connected from the 5U4 to one lead coming from the black cap? I only see one lead at each end of the black cap - maybe need a better pic of that 5U4 end if there are two leads coming out of that end.
 
coman61 said:
Thats also what I was wondering. If so we can see which side is ground. Then it must be a multi section 100uf? Should be 450V cap then.
Click to expand...

Our posts crossed again. He just clarified, the cap can is as before (my post #72) and the 100uF is the black one. He says that the black cap has 3 wires, one to ground (which I see) and two to the 5U4 (I only see one) & asked for better pic at that end.
 
there are two leads on the 5u4 side and one has a piece of cloth insulation stuck over it to keep it for shorting, there is also a lead on the other side going to ground. It doesnt look like this is subbed in place of a section of the cap can. Uppon closer inspection neither of those leads actually are wired to the 5u4 there just using unused terminals of the 5u4 socket as splice points. the wires go back to the bias pots
 
That connection is where the 40uf should be. Now I don't know why that black cap is there at all. The schematic shows that yellow wire going to the transformer.
 
OK, that last pic helped to clarify. So from what you're saying it seems that cap is connecting the pots to ground. Interesting that it does not indicate on the outside of the cap that it is two section? To be sure that there are two sections in there, have you measured the cap values, i.e. both 5U4 end leads (separately) to ground. Also, to be sure they are separate, check for any continuity between any of those leads (be sure the caps are discharged).
 
You must log in or register to reply here.
Back
Top Bottom