I can tell you one thing that these ir2188s ICs are a pain. I have been back and forth with them. Everytime a output blow you have to change all of them. I tried changing the ones that drives the blown fets but no luck, amp draws high current. Replace all, perfect.
Ok, thanks for the advice. In future i will change all parts on the drive board. I still have a lot to learn, specealy how the signals should look on the op´s and drivers. If i have this knowledge, it will make me easier to repair this amps.
Everytime a fet blows recheck all the fets and replace all the drivers,now I'm not taking any chances I'm even replacing all the small transistors, check all gate resistors.
Ok, i increased now the low voltage and found, that three banks getting hot, one bank still cold. I will take this drive board on my work at sea. There i have two weeks time to check and change everything.
The only stupid thing I did was tested the amplifier without the fets clamped to the heatsink,and increased the gain a bit too much and two fets popped. So now I have to start over again.
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If you removing the card to work on, make sure when you put it back all the pins make proper connection, these through hole pads get damaged easily by removing the card.
Use ChipQuik and you will never damage a via again. Also, it's much easier to remove the header from the main board than from the driver board.
MMBT3904
On the top of the Semiconductor Datasheets page (SDS shortcut), there are two SMD Codebook links. Those give you the part numbers for the codes.
On the top of the Semiconductor Datasheets page (SDS shortcut), there are two SMD Codebook links. Those give you the part numbers for the codes.
I need a diode for the power supply. Its written in the diagramm 1n4148 1w 37v. I find only with max 500mw. That one has a yellow ring. Can somebody help with the right one please?
There are likely two series diodes. One is a 1w 37v (voltage varies from about 36v to 39v). The other is a 1N4148. Is that possibly what you have?