nashou
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Post by nashou on Mar 18, 2019 17:55:20 GMT -5
Do you have another volt meter to try/confirm? Yep, using two voltmeters . the Yellow one doesn't do mV so to say, it does go to 3 decimal spaces. Checked Bias with that right after the Green meter when it was at 5mV's and it read .005 so I am pretty sure its ok. And I just changed Batteries when I got home at 4 pm.  then after a few minutes maybe 7-10  I had to power down as I have to run out for an hour or so. I'll check back . The pics above are of the left channel original driver board and original filtering cap , not the board I re capped or the 1000uf 35 volts cap I replaced. Nashou |
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Post by mastertech on Mar 18, 2019 18:05:27 GMT -5
Do you have any high value caps?
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nashou
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Post by nashou on Mar 18, 2019 18:16:05 GMT -5
Do you have any high value caps? Not higher than 35 volts , I don’t think .....but I just remembered I have a box of Black Gates somewhere . There might be a higher Value there . Are you thinking that maybe young the value it could lower the dc on the outputs? I could parallel some caps and see what happenes ? I was able to measure the voltage at the caps like you wanted me to before and there is 30.75 volts on the input to the cap. |
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Post by mastertech on Mar 18, 2019 18:40:26 GMT -5
And that 30.70v wire is going to the + side of the cap? I would like you to try a higher uf value cap, not necessarily a higher voltage.
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nashou
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Post by nashou on Mar 18, 2019 19:00:17 GMT -5
And that 30.70v wire is going to the + side of the cap? I would like you to try a higher uf value cap, not necessarily a higher voltage. Ok Back. Yes the 30,7 vdc goes to the + side of the cap. I'll look for some hight capacitor I think I have 25 volt ones up 4700 Vishay BC caps would those work? Nashou |
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Post by mastertech on Mar 18, 2019 19:05:35 GMT -5
25v is no good. Must be at least 35v (higher then applied voltage). If we use the schematic as a reference and we have the same 29v on that line to the cap and that schematic uses a 2200uf/63v cap then we should be looking in that range.
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nashou
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Post by nashou on Mar 18, 2019 19:07:49 GMT -5
crap, not sure I have one that high a voltage. I'll look again, have project boxes with various caps all over the place . I need to get organized .  Be back soon into the dungeon!!! Nashou |
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nashou
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Post by nashou on Mar 18, 2019 19:15:42 GMT -5
Ok I found the box of black Gates . And there is a 2200uf 35 vdc cap, two of them!!
Be right back ..............
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nashou
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Post by nashou on Mar 18, 2019 19:39:13 GMT -5
ok no change ,
After the time it took to upload video bias is now at 4.4 mV and DC speaker voltage is 6.85.
Cycling on and off did not get the DC to drop as before. Might need a few times of cycling to get it to do that again?
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nashou
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Post by nashou on Mar 18, 2019 20:00:37 GMT -5
Just a moment ago , keeps rising!!!  |
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Post by mastertech on Mar 18, 2019 20:36:59 GMT -5
Is that just 1 channel or both?
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nashou
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Post by nashou on Mar 18, 2019 20:39:55 GMT -5
Well, this is what we know
Figured out the hot heat sinks by realizing the trim pots are for Bias not DC offset.
With all output transistors removed as well as the amp board we still have DC.
Put new DC blocking cap and still have DC
So Only thing left in my view is the relay, or relay board .
, Might be from that board that its feeding back to the negative side of the DC blocking cap?
Just trying to figure this out taking into consideration everything we removed and still have DC.
Unless there is some continuity test I can do from the speaker outs to other places where there should not be
any continuity. Might be picking up DC from there? bad diode leaking somewhere?
Nashou
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nashou
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Post by nashou on Mar 18, 2019 20:40:58 GMT -5
Is that just 1 channel or both? just the one channel, one DMM on Bias the other on output. nashou |
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Post by mastertech on Mar 18, 2019 20:48:12 GMT -5
Is that the channel that has the soldered wires at the heatsink screw or the one that still has the device?
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nashou
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Post by nashou on Mar 18, 2019 20:54:08 GMT -5
Is that the channel that has the soldered wires at the heatsink screw or the one that still has the device? That video was of the right side amp, the one I re capped . Both heat sinks have those two brown wire soldered or epoxy'd together . The other amp , the left one with those wires intact not broke free is also acting the same way but a bit more stable. I put those bundles wires back into the fastener and squeezed the crimp around them. so its like the other. But the contact is probably not as good as the one that was not broke free. Nashou |
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