the only thing i did in between distortion and smoking speakers was changed to a set 6x9's that cannot take a decent wattge, from a fi q 15 handling 1000rms watts. my guess is the 6x9's couldnt handle the brunt of the eradict power the amps putting out right now.
i did not change anything component wise since first power up. i havent even removed the board from the amp since first testing.
i will check the connections on all the replaced output transistors.
if i find all good connections, whats the next thing to check?
i did not change anything component wise since first power up. i havent even removed the board from the amp since first testing.
i will check the connections on all the replaced output transistors.
if i find all good connections, whats the next thing to check?
If it will power up, measure the DC voltage directly across the speaker terminals (red probe on the positive speaker terminal and the black probe on the negative speaker terminal) for each channel. Post the DC voltage for each channel. Again, no input and no speakers connected.
Use a 20 amp fuse if it won't power up via a 15 amp fuse. I'm assuming that you're using ATC/ATO fuses and not glass fuses.
im using ato fuses. amp even blows a 30 amp fuse after 1-2 minutes.
i will check dc voltage right now. but when i tried to check dc voltage earlier, i got nothing. i will check again though and post results.
thanks
i will check dc voltage right now. but when i tried to check dc voltage earlier, i got nothing. i will check again though and post results.
thanks
well, i was removing the screws for the mesha boards and realized when i was soldering a mosfet back to the mesha board i had a bead of solder squeeze out of the side. this piece of solder touched a screw that screwed the boards back onto the heatsink. This happened on a 36p15 and a 28n15.
im guessing this would ground out the mosfet frying it also.
so maybe back in the same boat i started in with shorted mosfets.
im guessing this would ground out the mosfet frying it also.
so maybe back in the same boat i started in with shorted mosfets.
i did remove the screw, and clear away the solder. i attempted to check the fets, i kept getting readings in the negative range, and some give no readings at all. that meter is driving me crazy. i will check again tonight.
alright, tested both channels worth of mosfets all test good.
tested all .1 ohm resitors all test good.
dunno where to go next with troubleshooting.
symptoms are: amp comes on, stays on without protect light for about 2 minutes, then go into a "flashing" protect light, then blows fuse(30 amp) about a second after that.
amp makes no sound most of the time while on, maybe a split second of distorted "burp" then off again(on both channels).
amp also has same symptoms with no speakers connected, and with output audio signal going into amp.
tested all .1 ohm resitors all test good.
dunno where to go next with troubleshooting.
symptoms are: amp comes on, stays on without protect light for about 2 minutes, then go into a "flashing" protect light, then blows fuse(30 amp) about a second after that.
amp makes no sound most of the time while on, maybe a split second of distorted "burp" then off again(on both channels).
amp also has same symptoms with no speakers connected, and with output audio signal going into amp.
Do the outputs in either channel get hot in 2 minutes?
Is there more than a fraction of a volt of DC (measured directly across the speaker terminals for each channel) at any time (from turn-on till protect mode)?
Is there more than a fraction of a volt of DC (measured directly across the speaker terminals for each channel) at any time (from turn-on till protect mode)?
voltage fluctuates from .2 to .10 on channel 2. channel one from 0 to about .2.
voltage goes up to higher numbers after amp is shut off then slowly dies down to zero.
no mosfets get hot, but amps blinks protect almost instantly now.
i didnt let it stay on more than 30 seconds, as protect kicked over, i can go try for 2 minutes if needed.
voltage goes up to higher numbers after amp is shut off then slowly dies down to zero.
no mosfets get hot, but amps blinks protect almost instantly now.
i didnt let it stay on more than 30 seconds, as protect kicked over, i can go try for 2 minutes if needed.
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yes no input signal at all. also only thing on speakers terminals is (2) dmms to check dc volts.
With no speakers connected, drive a strong signal into the amp. Does either channel produce any significant DC?
If there is no DC on the speaker terminals, it should be safe to connector to the amp (but watch the cone and disconnect the amp if the woofer pulls in or pushes out from the point of rest).
Connect it to the 'good' channel and drive a signal into that channel only. Does it play for 30 seconds and produce clean audio?
If there is no DC on the speaker terminals, it should be safe to connector to the amp (but watch the cone and disconnect the amp if the woofer pulls in or pushes out from the point of rest).
Connect it to the 'good' channel and drive a signal into that channel only. Does it play for 30 seconds and produce clean audio?
yesterday i tried both channels for good audio, i got nothing but the random burping distortion.
i can test for dc again, with a strong signal, and i will let you know what happens.
i can test for dc again, with a strong signal, and i will let you know what happens.
alright did a test with signal going in, went straight to protect mode. got .002 to .000 volts dc from right channel(the one i repaired) and getting .000 to left channel. once remote voltage is taken off, i get about .5 dc volts to right channel and .000 on left
power and protect, protect blinks on and off with some excessive power pull, like the lights dimm slightly when it blinks. power stays on steady blue.
With no power applied, measure the resistance from the center leg of EVERY component on the heatsink to the heatsink (one probe on a bare part of the heatsink and the other on the various center legs). Do any read near 0 ohms?
all output fets test 15-25 mega ohms. On power side everything reads good but the 74344gs some read OL some read negative readings, some read low mega ohm numbers.
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