This amp has isolated primary and secondary grounds. When you unplugged the RCAs, the secondary ground was disconnected from the primary ground. That's why you read 0v.
The opto-coupler has connections to both the primary and the secondary. That's why you have to connect the small black wire (secondary ground wire) to the main ground.
The opto-coupler has connections to both the primary and the secondary. That's why you have to connect the small black wire (secondary ground wire) to the main ground.
Sorry, I don't know what the opto-coupler looks like. Is it one of those the two long skinny ones between the 4570 & 5533? One is shown in picture #1(MSP08A03-103G) and the other is in picture #2(B102GA) of post#117.
Also the ones in the pictures have 8 pins each.
Also the ones in the pictures have 8 pins each.
I connected the small black wire to the main ground wire. The opto-coupler on the bad side reads:
pin1 0
pin2 0
pin3 0
pin4 23.5v
pin5 0
pin6 14.5v
Not even close to the readings on the good half.
pin1 1.25v
pin2 0
pin3 0
pin4 -15v
pin5 -15v
pin6 -15v
pin1 0
pin2 0
pin3 0
pin4 23.5v
pin5 0
pin6 14.5v
Not even close to the readings on the good half.
pin1 1.25v
pin2 0
pin3 0
pin4 -15v
pin5 -15v
pin6 -15v
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It appears that the black diode is defective. It should have no more than 0.7v across it and it has about 10x that.
If you don't have one, you can jump it temporarily to see if you get -15 to the gates of the muting transistors and to see if the weak channel will produce clean audio.
If you don't have one, you can jump it temporarily to see if you get -15 to the gates of the muting transistors and to see if the weak channel will produce clean audio.
To confirm, Diode "G"?_
I do have one, I will replace and test.
Is the white grease on the transisters lithium, or something else?_
I do have one, I will replace and test.
Is the white grease on the transisters lithium, or something else?_
It's zinc oxide in a silicone base. Solder it across the other diode for now.
Yes, the black diode on the side of the white diode.
Yes, the black diode on the side of the white diode.
Replaced diode to the right of "F". My last fuse popped on power up I will recheck as soon I find another fuse. Thanks Matt.
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The amp seems to be working now!!!
w/15 amp fuse, both speakers seemed to be loud and clear.
After hooking the amp back up in the car I must have done something wrong because now both channels sound great individualy but with the balance centered the subs seem to drop in volume and loose there bottom end. any idea's?
w/15 amp fuse, both speakers seemed to be loud and clear.
After hooking the amp back up in the car I must have done something wrong because now both channels sound great individualy but with the balance centered the subs seem to drop in volume and loose there bottom end. any idea's?
Perry Babin is an Amp Repair GOD!!! Everything seems to be working fine(pic#1).
I just need to put the wiring looms covers back on to clean up the look. You were correct; one of the subs must have been out of phase although I think it may be in the box. I triple checked the speaker wires and they are all correct going to the box.
Is there a way to check the box's terminals with a meter to tell what side of the speaker is going where or do I just pull the subs and look?_
Or should I be using the mono low pass output(pic#2 ) since one of the outputs is inverted?_
I am not trying to be lazy here; it’s just that they are behind a false wall when viewing from the trunk/outside. It is there so when hauling stuff it cannot contact and hurt the speakers, and to the untrained eye, you cannot see anything.
This has been a great learning experience for me, I learned a lot on your website, and it is a great reference for us "Electronically challenged" people. I do have to say nothing teaches better than doing it. There were things that I read that made no sense until I was testing those parts "hands on", it was then that I could start to grasp how it operated.
Again, thank you so much.
I just need to put the wiring looms covers back on to clean up the look. You were correct; one of the subs must have been out of phase although I think it may be in the box. I triple checked the speaker wires and they are all correct going to the box.
Is there a way to check the box's terminals with a meter to tell what side of the speaker is going where or do I just pull the subs and look?_
Or should I be using the mono low pass output(pic#2 ) since one of the outputs is inverted?_
I am not trying to be lazy here; it’s just that they are behind a false wall when viewing from the trunk/outside. It is there so when hauling stuff it cannot contact and hurt the speakers, and to the untrained eye, you cannot see anything.
This has been a great learning experience for me, I learned a lot on your website, and it is a great reference for us "Electronically challenged" people. I do have to say nothing teaches better than doing it. There were things that I read that made no sense until I was testing those parts "hands on", it was then that I could start to grasp how it operated.
Again, thank you so much.
Attachments
If you can see the speakers, you can use a battery to see if they're in phase.
http://www.bcae1.com/images/swfs/speakerphase.swf
Unless you really just want to know where the problem is, it's not really important. If it's producing good bass, the speakers are in phase.
http://www.bcae1.com/images/swfs/speakerphase.swf
Unless you really just want to know where the problem is, it's not really important. If it's producing good bass, the speakers are in phase.
Back Again. The amp is still running but I have noticed that the right channel(the repaired one) is not producing full power. I have switched the RCA's to verify that one channel wasn't getting a stronger signal but that wasn't it. So I switched the subs to see if that may have had something to do with it, but still the same result. After running the amp at about 1/3 power for 5-10min the left half is noticably warmer to the touch than the right channel. Right channel seems to have about 1/2 to 2/3 the power that the left channel is producing. since this amp is actually two 2 channel amps bridged, I'm starting to think only one of the 2 channels is working on the right channel.
I checked the gain pots again and both channels are getting 1v input.
any idea's anyone_?
I checked the gain pots again and both channels are getting 1v input.
any idea's anyone_?
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I've got two of these amps on the bench. Both had a leaky transistor that controls the amplitude voltage driving the bases of the power supply switching transistors. It would produce a high output voltage which stressed the filter caps and cause that half to run warm.
Perry might be able to elaborate.
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