The other problem is heat. Someone has added extra fans and an extra thermistor to the output section and there is this. Heat between these two. I checked the voltages across the diodes in the power supply section. They are all ok. I have my input 50hrtz at the output transistors.the complaint was it was over heating. I know that the amp comes with the one thermistor and 2fans. Could the extra load and thermistor be causing an issue with the kA3525, and the extra load from four extra fans over load the curcuit?
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Has almost no thermal paste applied and the four transistors in one bank, were replaced and they left the driver transistors the same....no new thermal paste? I'm going to check all the recifiers as well. I do have a good drive signal. I'm not sure how they thought that it doesn't have a thermal light just a protection led.
You need to talk to the owner to get more information.
He may have been running it into a very low ohm load.
He could have a bad speaker or a shorted wire.
Was the heatsink getting far too hot to touch and that why the think it's overheating?
Was it heating up at idle?
You may replace all of the FETs and the problem is not with the amp. Or, the problem could be on the driver board (too much current through constant current source).
If there is insufficient heatsink compound, the heat cannot be transferred to the heatsink efficiently.
He may have been running it into a very low ohm load.
He could have a bad speaker or a shorted wire.
Was the heatsink getting far too hot to touch and that why the think it's overheating?
Was it heating up at idle?
You may replace all of the FETs and the problem is not with the amp. Or, the problem could be on the driver board (too much current through constant current source).
If there is insufficient heatsink compound, the heat cannot be transferred to the heatsink efficiently.
The photo i uploaded earlier in post, where the soder has that appearence. Post #5 Sorry photo was taken with phone, doesnt save on device. It was drawing about 5amps not 2 high but the 2600.1 draws a nom 2.6Amps idle
I removed the entire bank of 5 transistors to test them. In tester and with ohm reader. Seem ok
Drivers are the (kta1277, 2sc3228) Replacement?
And the larger transistors on the driver board A1837-C4793 (i have these but cant guarentee there authenticity (EBAY A Long time ago)
Ill try without those transistors.
Yes All Matching date codes
I removed the entire bank of 5 transistors to test them. In tester and with ohm reader. Seem ok
Drivers are the (kta1277, 2sc3228) Replacement?
And the larger transistors on the driver board A1837-C4793 (i have these but cant guarentee there authenticity (EBAY A Long time ago)
Ill try without those transistors.
Yes All Matching date codes
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No carbonized, Ill check it again. All the resistors are good. That area appeared to have heat on it, dry soder heat. Kind of hard to explain. but these are the two fets that heated up. Likely all would have had i not cut it off. i noticed the difference of appearence, before i reinstalled the rectifiers. The current was 2amps without the rectifiers. Which was alittle high for just the PS.
Which transistors actually drive the Output transistors?
Which transistors actually drive the Output transistors?