With the inductors pulled Q24-27 will not have B+ voltage. Check them with an ohmmeter.
If they check OK, install the Memphis inductors.
If the current draw still exist, pull the primary of one transformer at a time to isolate the problem transformer.
If there is a shorted winding, or cracked core it may be difficult to find with a visual inspection, and will require process of elimination.
If they check OK, install the Memphis inductors.
If the current draw still exist, pull the primary of one transformer at a time to isolate the problem transformer.
If there is a shorted winding, or cracked core it may be difficult to find with a visual inspection, and will require process of elimination.
Drivers check good, drive is present without inductors, installed the inductor Friday m the Memphis amp same current draw. Transformer is next.
Which resistor specifically? Just curious. I can't tell you how many times a thread of solder had me running around in circles!!
Did you install the outputs yet?
Did you install the outputs yet?
Yes, only two I had left over they were all short except for 2 I kept to test the curcuit with. Full audio no issues with diode d7 installed. It actually dripped from me removing the mosfets on to the 10ohm hole through in the power supply, it was on the underside and made like a splatter connecting the two, causing the short......SMH..at least I found it before pulling more large components.
I don't have the ixta36n30p, any other outputs stable in these amplifiers? Fqa38n30 I have. I ordered the proper mosfets.
Not sure about the FQA38N30. The IXTQ36N30 are available from Mouser. Link below.
https://www.mouser.com/ProductDetail/IXYS/IXTQ36N30P?qs=sGAEpiMZZMshyDBzk1/WizrSbRfT/m2U9q0W7WFOMFU=
https://www.mouser.com/ProductDetail/IXYS/IXTQ36N30P?qs=sGAEpiMZZMshyDBzk1/WizrSbRfT/m2U9q0W7WFOMFU=
The amplifiers audio at the speakers is very static like o. Bass notes. As the bass notes hit is just crackles. So now I need help to trouble shoot an audio problem.
Check the op amps, sometimes even the potentiometers can make junky and weird stuff. Clean them up.
Check with an ohmmeter between power and speaker(Neg terminal) Grounds. This should be zero. If not check the R7-0Ω resistor.
Be sure that all of your Rail voltages are normal,especially +/- 15 volt supply to preamp board.
Check to be sure you have proper drive to the outputs and a good triangle wave on pin 4 of the U202-LM361 and the drive out the -DRV and +DRV test point on the corners of the class D amp look good. Post your screenshots.
If all else looks OK, signal trace the preamp board and check the pots as Lenin89 suggested.
Be sure that all of your Rail voltages are normal,especially +/- 15 volt supply to preamp board.
Check to be sure you have proper drive to the outputs and a good triangle wave on pin 4 of the U202-LM361 and the drive out the -DRV and +DRV test point on the corners of the class D amp look good. Post your screenshots.
If all else looks OK, signal trace the preamp board and check the pots as Lenin89 suggested.
So I pulled d7 instant current, found a power supply mosfet that shorted. Q39 I'm removing the remaining. Mosfet in that bank to. Test them. Also the rectifiers.
Rectifiers that are installed. These look, correct? The output transistors are also shorted again. We repaired this entire amplifier once already. So the power supply was all new. Original drivers.
The outputs were OK
2 are now short most likely failed after
Removed all output transistors and tested them. Removed rectifiers, with d7 install it was building drive then dropping it, over and over.
The power supply mosfet are installed and drivers output transistor and rectifiers removed. The amplifier draws current immeadatly. Ground zero again.
The outputs were OK
2 are now short most likely failed after
Removed all output transistors and tested them. Removed rectifiers, with d7 install it was building drive then dropping it, over and over.
The power supply mosfet are installed and drivers output transistor and rectifiers removed. The amplifier draws current immeadatly. Ground zero again.
Attachments
The bar labeled SGND should work. You will find it runs parallel to the side with the output mosfets. To be sure check the continuity from bar to the Negative speaker terminal. Sometimes the solder on the bar needs to be reflowed on both top and bottom sides of the board.
I drove a signal into the amplifier to see the drive. Noting was present. Then I noticed the amplifier is in protection. D7 is removed
- Status
- Not open for further replies.