Got it non working, change vr251 vr151, they make contact when touched.
Bias went on and there was sound, service manual says bias 100mV, that must be all four points summed together? so 25mV per point, bias is set 17mV, lil bit down cause fan seems not working, did not want it to overheat.
Year later seems to be left channel is not as loud as right.
it is an old amp, might need handful of new parts inside
http://users.atw.hu/jeges2009/_private/kapcsolasok/pioneer Gm-x802.pdf
here is service manual
What can i do about it?
Bias went on and there was sound, service manual says bias 100mV, that must be all four points summed together? so 25mV per point, bias is set 17mV, lil bit down cause fan seems not working, did not want it to overheat.
Year later seems to be left channel is not as loud as right.
it is an old amp, might need handful of new parts inside
http://users.atw.hu/jeges2009/_private/kapcsolasok/pioneer Gm-x802.pdf
here is service manual
What can i do about it?
yes now after posted and start to think, this amp is bridged to sub.
what i did allready is i changed subwoofer polarity, if it was acoustic issue.
Yes it could be that, sub is closer to drivers seat than highpass speaker, sub has 18db/oct low pass and high pass is 12db/oct, might be that phase does not match with left way both polarities are bad.
dont think its head unit, highs comes within balance, its just bass
what i did allready is i changed subwoofer polarity, if it was acoustic issue.
Yes it could be that, sub is closer to drivers seat than highpass speaker, sub has 18db/oct low pass and high pass is 12db/oct, might be that phase does not match with left way both polarities are bad.
dont think its head unit, highs comes within balance, its just bass
nope, did not fixed it.
cracking noises sometimes when slightly tapping this area, this area heats a little. might be normal. R265 has changed color little bit, sometimes i measured it 27-31k when it was on the board, but it did change, might be something else causing it? i think it should be 33k.
but i allready took these of so changing them.
i dont like this heat issue problem goes away when amp stays on for a while, sure it has to be bad connection somewhere
The service manual site you used was blocked by malwarebytes. Use either of the following in the future.
Service Manual free download,schematics,datasheets,eeprom bins,pcb,repair info for test equipment and electronics
Service manual, eprom result list | Elektrotanya
Is there any switch or potentiometer that will make it crackle if you move the actuator/shaft?
Service Manual free download,schematics,datasheets,eeprom bins,pcb,repair info for test equipment and electronics
Service manual, eprom result list | Elektrotanya
Is there any switch or potentiometer that will make it crackle if you move the actuator/shaft?
i cleaned low pass switch, potentiometers seems ok.
for me that crack is something else than potentiometer crack.
Dropbox - pioneer Gm-x802.pdf
here is pdf
for me that crack is something else than potentiometer crack.
Dropbox - pioneer Gm-x802.pdf
here is pdf
cant say if its heating up or me moving the amp but im pretty sure it just went away just amp being on.
i know more tomorrow when switching it on.
there are some caps on that area, can old cap do it that it wont switch bias on (sorry cant say this any better) and if i touch the area some cap or other component start to work.
if problem is on tomorrow im gonna video it, its quite sketchy
i know more tomorrow when switching it on.
there are some caps on that area, can old cap do it that it wont switch bias on (sorry cant say this any better) and if i touch the area some cap or other component start to work.
if problem is on tomorrow im gonna video it, its quite sketchy
I don't watch videos that are posted but someone else may find it useful.
I've never seen a cap do that but I've seen leaked electrolyte do strange things. The crackling is generally due to defective transistors (at least, that's the case in older equipment). Those are typically thermally sensitive so heating/cooling help to find defective components.
I've never seen a cap do that but I've seen leaked electrolyte do strange things. The crackling is generally due to defective transistors (at least, that's the case in older equipment). Those are typically thermally sensitive so heating/cooling help to find defective components.
Seems to work again, no cracks when touching that area, clean sound.
there is power on bulb and pioneer logo bulb, they were burned so i put led in.
i played hard and even fan does work now. This was earlier very high bias and fan did not go on even frying pan level of heat.
i heated/soldered again some points from that area, that might be the whole issue
there is power on bulb and pioneer logo bulb, they were burned so i put led in.
i played hard and even fan does work now. This was earlier very high bias and fan did not go on even frying pan level of heat.
i heated/soldered again some points from that area, that might be the whole issue
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amp heats up quickly, 94mv dc output on non working channel, was something like 2mv when measured when it was working last time.
contiunity on output transistors seems to be same between 1 and 3 seems to be similar between all 8.
this time output is on, there is 15mv of bias on all 4 shunts and it stays even when its cold, soldering fixed that.
must draw few amps current cause my 0,75mm2 wires warms up too
contiunity on output transistors seems to be same between 1 and 3 seems to be similar between all 8.
this time output is on, there is 15mv of bias on all 4 shunts and it stays even when its cold, soldering fixed that.
must draw few amps current cause my 0,75mm2 wires warms up too
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did not find my magnifying glass but pretty much every transitors on the picture is now re-soldered, hole on the board is big and leg is thin.
i´ve used all my "its fixed" cards so lets see
If the bias isn't holding, it sounds like a bad bias pot, a bad connection in the bias circuit or possibly a defective bias transistor.
The large holes are a serious problem. In many of the pioneer amps, the electrolytic capacitors stood a bit off of the board and you had to avoid touching them because they would break the solder connections. It's not only pioneer that does this.
The large holes are a serious problem. In many of the pioneer amps, the electrolytic capacitors stood a bit off of the board and you had to avoid touching them because they would break the solder connections. It's not only pioneer that does this.
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