Perry removed all driver transistors from output driver boards , they all check out 100% and no leakage , and all resisitors check out as well. Do you think it can be the 393 ?
If I'm not mistaken, at one time the amp was drawing excessive current with only the outputs (no driver boards in place) and that suddenly stopped (no excessive current). Is that accurate?
Yes that stopped , after you tolded me to check for leakage on the output transistors , and there was 4 bad output transistors ( causing high current draw with or without output driver boards ). Now it is only drawing current when the output driver boards are in . The output transistors were in ( good ones ) and the output drive boards were in , high current draw . After you told me to remove output driver boards ( still had output transistors in ) high current stopped . I checked all the output driver transistors all check out 100% and no leakage and resistors . So do you think it can be the 393 on the outputs ?
I don't think the 393 has anything to do with high current draw. It's part of the over-current protection circuit.
Is the driver board with the LM361 on it in or out of the board?
Is the driver board with the LM361 on it in or out of the board?
Yeah thats what its for .
On the second page the pictures show the LM361 , it is on another board and still is in place .
On the second page the pictures show the LM361 , it is on another board and still is in place .
Reinstall the output driver boards and remove the board with the LM361.
Does it power up without drawing excessive current?
Do you have ~0v on the tabs of all of the output transistors?
Does it power up without drawing excessive current?
Do you have ~0v on the tabs of all of the output transistors?
Perry ok I did reinstall the driver boards and removed the board with the B-52 . High current draw stopped ! Yes 0.000v on the tabs . So the B-52 is bad do I order ?
There's been a problem with the sync circuit on a few amps like these. Remove Q41 from the power supply driver board and reinstall the B52 board. Does the excessive current draw stop?
If so, does the amp function normally?
If so, does the amp function normally?
Perry I have a memphis 1000 amp that needs to be fixed as well the design of this amp and the db 1200 are the same but the id locations and markings are alil different . Q41 center is connected to the 494 pin 5 , on the db 1200 it is Q05 c3198 . Ok removed , reinstalled B52 board . Turned on power no high current draw but R62 22ohm resistor started to glow and unsolded it self from the board and losted its color bands ( on the memphis amp the resistor lable is R52 22 ohms ) , and the output transistor 9640 started to get hot and spilled alil solded out of its back side , but the 640s stayed cool ? Still no sound. What could be going on ?
Did any of the other 9640s get warm when the other one overheated?
R52 feeds the voltage regulators and has nothing to do with the transistor connected to pin 5. Confirm that none of the regulators or capacitors on the regulators are shorted. Also check for solder bridges in the area.
R52 feeds the voltage regulators and has nothing to do with the transistor connected to pin 5. Confirm that none of the regulators or capacitors on the regulators are shorted. Also check for solder bridges in the area.
Perry yes I had 2 output 9640s and both got hot . The other 2 output 640s stayed cool.
Ok will do , I didnt know what it was connected to or what to check thank you . Funny cause it has never done that nor have I seen a resistor get that hot ?
Ok will do , I didnt know what it was connected to or what to check thank you . Funny cause it has never done that nor have I seen a resistor get that hot ?
There are generally more IRF9640s than 640s. If only half of the 9640s got hot, it could indicate that there is a problem on the driver board. There's generally one set of drivers for the 640s and two sets of drivers for the 9640s.
Perry ok I will put in 4 IRF9640s and 2 640s and test to see if they get hot. On the R52 getting hot , there is a disk cap shorted next to the voltage regulators . Thank you .
Perry one regulator still has a short it wasnt the disk cap it meters 100% as dose a electro cap. Ive tracked one side of the regulator to the output driver boards. Iam thinking that there is a bad part on one output driver board that causing the outputs IRF9640 to get hot and the one regulator too . Do you think so ? Oh Yes I also bought a copy of your amp repair disk , I can wait for it LOL !
Did you remove the regulator to see if it was shorted?
I'll try to get the discs out today but it may not go out until tomorrow.
I'll try to get the discs out today but it may not go out until tomorrow.
Perry the regulator test 100% it has been out for testing other parts. Ok you sound like your a man of your word , no worries .
Yes but I dont have the amp in front of me but its the one closer to the output side . I read 0 ohms on pin 1-3 .
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