Hi all, first post but cant figure this out on my own.
Amp is quite old Soundstream lilwonder 4.480, I was using it as first 2 channels driving speakers and 3;4 channels small pioneer shallow mount sub.
Problems started as sub was loosing signal, checked wiring and filter switch and could not find any problems, after cycling filter switch many times sub seemed to work in LPF. But after a while sub burned and amp was in protect mode.
So I replaced small power transistors and two D988 transistors, amp is out of protect
I was happy, but before putting it back in car decided to test it. First two channels are ok. But the 3. and 4. channels seem not to work in LPF, HPF, FULL modes, it works only in BPF, but is crazy loud, gain to minimum, same settings as channel 1,2 except 1,2 running at FULL. 3. and 4. channels are too loud and distorted.
Where to look for problems? I have tested all diodes marked with Z. And small transistors 2sd667 and 2sb647 at channel 3,4 side.
What else to test?
Thanks a lot for any help.
Adding pics of amp:
Amp is quite old Soundstream lilwonder 4.480, I was using it as first 2 channels driving speakers and 3;4 channels small pioneer shallow mount sub.
Problems started as sub was loosing signal, checked wiring and filter switch and could not find any problems, after cycling filter switch many times sub seemed to work in LPF. But after a while sub burned and amp was in protect mode.
So I replaced small power transistors and two D988 transistors, amp is out of protect
I was happy, but before putting it back in car decided to test it. First two channels are ok. But the 3. and 4. channels seem not to work in LPF, HPF, FULL modes, it works only in BPF, but is crazy loud, gain to minimum, same settings as channel 1,2 except 1,2 running at FULL. 3. and 4. channels are too loud and distorted.Where to look for problems? I have tested all diodes marked with Z. And small transistors 2sd667 and 2sb647 at channel 3,4 side.
What else to test?
Thanks a lot for any help.
Adding pics of amp:
Unfortunately all I have is multimeter.
When amp is running with input audio signal, normally channels 1 and 2 by measuring at output speaker side with multimeter set to AC it is around few volts. But channels 3,4 Set to BPF are around 20V with gain set to minimum.
Emailed soundstream and asked for schematics, lets see what they say.
Thanks.
Sorry for that!
Most of them have no voltage on pins 1 and 7,
but 3 of them had:
One had 0,38V on pin 1
Two 0,12V and 0,18V on pin 7
Thanks!
yes, seems ok audio at Full and LPF.
HPF no sound in one channel.
BPF crazily loud.
All tested with gain set to minimum.
Thanks for the help!!!
amps seems to work now as it should.
Got crazy and resoldered half of amp, channel 3;4 side. But still nothing.
Apm had some broken and cold joints see pic. Today worked a bit on input board almost soldered over all points Some of them as soon as I touched with soldering iron formed a hole, dont seem too good to me.
So after all this mess it started to work correctly
amps seems to work now as it should.
Got crazy and resoldered half of amp, channel 3;4 side. But still nothing.
Apm had some broken and cold joints see pic. Today worked a bit on input board almost soldered over all points
Some of them as soon as I touched with soldering iron formed a hole, dont seem too good to me.So after all this mess it started to work correctly
hello again, now in 2012
Having trouble with same amp.
Most of the time it works ok, but sometimes seems to be changing filter settings from quite normal base levels to something more on highs. But this is not so annoying as a some kind of short circuit what can be heard in front speakers at least those I could check by lowering volume to 0 and this short sound or current is moving speakers. I don't know where to look for a problem because this only happens like once a day, at some moment when car is warmed up. As this problem appears only for short period of time, haven't had luck to stop and troubleshoot, its usually on the way to work.
So it is definitely not stereo, that has been replaced, and managed once to disconnect rca`s so problem could be only in amp or wiring somewhere?
Sorry I try explain as best as I can, and I hate that it is not possible to troubleshoot this for some longer period of time. No worries about speakers, those are not good anyways, have new amp also, just want to know if this could be fixed or let go for parts...
Would like to know what to look for?
Thanks!
Having trouble with same amp.
Most of the time it works ok, but sometimes seems to be changing filter settings from quite normal base levels to something more on highs. But this is not so annoying as a some kind of short circuit what can be heard in front speakers at least those I could check by lowering volume to 0 and this short sound or current is moving speakers. I don't know where to look for a problem because this only happens like once a day, at some moment when car is warmed up. As this problem appears only for short period of time, haven't had luck to stop and troubleshoot, its usually on the way to work.
So it is definitely not stereo, that has been replaced, and managed once to disconnect rca`s so problem could be only in amp or wiring somewhere?
Sorry I try explain as best as I can, and I hate that it is not possible to troubleshoot this for some longer period of time. No worries about speakers, those are not good anyways, have new amp also, just want to know if this could be fixed or let go for parts...
Would like to know what to look for?
Thanks!
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