Audiobahn A6004V

[mike49504]

I put new power supply fets in this amp. And hooked it up to see if i had audio on all 4 channels.

Well 3 of the channels are dead no output. I place black meter probe on secondary center tap and red probe on middle legs of outputs and its producing rail voltage on all outputs.

Just have no output on 3 of the 4 channels. Wondering where i start?

[Perry Babin]

Have you checked all pots and switches?

Have you confirmed that the signal is reaching the circuit board?

Do ALL of the op-amps have both positive and negative voltage?

Do you see any transistors with the circuit board designations, QM1, QM2, QM3, QM4?

Does it look anything like the attached photo?

[mike49504]

Heres some pics of the amp. Ill have to check to see if i can find the locations

[mike49504]

I checked all op amps on the main board and the rca board. I thve + - 15 volts on all of them.

Wondering where do i probe to see if im getting audio to the main board??

Also i didnt aee Q1,2,3,4 I do more checking though

[Perry Babin]

Check for signal where the shielded cable from the RCA jacks goes into the main board. Confirm that all 4 channels are reaching that point.

[jol50]

I used to put a tone CD in my HU on repeat at 60Hz or so, then I would follow the signal with the probe on AC voltage. Every time the tone stopped and repeated I would see the meter zero out. Was before I had a scope.

Perry is right investigate RCA and gain pots for user damage/wear first before you try to trace it. Also look at board for blown traces, other obvious things, and with those make sure no liquid came in the fan and got on the board.

Most of the ones I saw were the T series not V. They had the darker board Perry posted. That light blue is just like the Magnum amps supposedly sold via MTX, the emitter resistors and lugs are the same. Actuallly iirc the smaller visonik were the same as the magnum...or built in the same house.

[mike49504]

I got the front 2 channels up and runninng.

Rear channels still dead. i tested the cable for the rca jack where it connects to the board and im getting signal there

[Perry Babin]

If I'm not mistaken, two channels go to the small board and then go back to the main board. Do you see 4 points on the jumpers between those two boards where you have signal?

[mike49504]

Ok for the rear channels. Im getting signal to the smaller board but no signal back to the main board

[Perry Babin]

Confirm that all op-amps on that board have both positive and negative supply. If they do, confirm that all other pins on those op-amps are VERY near 0v DC.