Put one FET in each bank on the side that causes the a protection issue. Remove the toroid inductor L105 or L106 on the side with a problem and power up. If this allows the amp to come out of protection, the inductor may be causing an issue.
Post a pic of bad inductor. Examine the inductor closely. Look for delamination, cracked core. Check the insulator for perforations
does this mean its something to the right of the inductors if nothing changed when i swapped them and it seems to run fine without them installed?
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You still have one bank on each side to populate. You should have 2 Irf9640 and 1 Irf640 on each side of board.
My mistake, you are correct. Replace both inductors and remove all outputs. Check for drive at the common side of gate resistors.
48v on the positive rail and -55v on the neg. rail. if I drive signal into it I get a 60hz sine wave
Now its cycles in and out of protect with fets in on either side. Im making negative progress. im stumped. I replaced the driver transistors with PBHV8115 and PBHV9115. Do you think that might be the problem?
Based on the following link the PBHV8115 and PBHV9115 appear to be replacements 8115 for 4373y and 9115 for 1661y.
KTC4373Y npn smd sot-89 transistor complementary pnp, replacement, pinout, pin configuration, substitute, smd marking code CY, equivalent, datasheet
KTC4373Y npn smd sot-89 transistor complementary pnp, replacement, pinout, pin configuration, substitute, smd marking code CY, equivalent, datasheet
When you say "that resolved the issue" Do you mean the amp came out of protection? Was there ever a condition when you had drive on one side or the other?
Replace the Inductors, and remove all of the output mosfets. Lift R11-10k ohm. You will find it near Q10-3875GR. This should disable protection. If amp Powers up, check for drive/ squarewave at the gate resistors. Post screenshots for all banks.
Q113,135-A1361, Q104,126-C3503
Replace the Inductors, and remove all of the output mosfets. Lift R11-10k ohm. You will find it near Q10-3875GR. This should disable protection. If amp Powers up, check for drive/ squarewave at the gate resistors. Post screenshots for all banks.
Q113,135-A1361, Q104,126-C3503