Full rebuild.
I've already removed all the FETS in the PS section and the Output section.
All dead.
Output driver board for the class D is still in place as I have to fix the PS section first.
I've checked the gate drive in the PS just before the gate resistors (as this ones also have to be replaced).
I don't think this is normal. Two of the banks driving one of the transformers look shifted upwards. The other one looks normal. Pictures attached. So I think i will have to rebuild also the PS board - i think it is the buffer driver transistors.
I've already removed all the FETS in the PS section and the Output section.
All dead.
Output driver board for the class D is still in place as I have to fix the PS section first.
I've checked the gate drive in the PS just before the gate resistors (as this ones also have to be replaced).
I don't think this is normal. Two of the banks driving one of the transformers look shifted upwards. The other one looks normal. Pictures attached. So I think i will have to rebuild also the PS board - i think it is the buffer driver transistors.
Attachments
As much as I could see the markings these transistors are BE RN and DK RG which I believe are: BCX55-16 and BCX52-16 and these I can order from Farnell.
2SB1260 and 2SD1898 are impossible to find in my region.
2SB1260 and 2SD1898 are impossible to find in my region.
Look at the connections for the transistors. The PNP transistors will have their collectors directly connected to ground. Use whatever you can get but make sure you have the NPN and PNP in the correct locations.
I've mistyped the DF with the DK...and got it all wrong.
The marking for the NPN's is NOT "DK" but "DF" - which indeed comes as 2SD1898 so no matter what's the marking on the PNP's, they are for sure 2SB1260...
As I stated before, they are unavailable in my region. So I will use BCX55-16 for 2SD1898 and BCX52-16 for 2SB1260.
Driver board has not become conductive but there are some burnt traces...is there anything better and more reliable than jumper wires ?
I've never had jumper wires fail but you have to use common sense. What part of using jumper wires would you believe that makes them unreliable?
Power Supply section fixed. Pain in the a** to fix the PS buffer transistors traces but i managed it.
Driver board - DWM3640 - rebuild - done.
I've manage to try the amp with only one MOSFET irfp264n per bank. Runs fine. There is clean sinewave at the output. Just waiting now for whole new batch of irfp264n.
Driver board - DWM3640 - rebuild - done.
I've manage to try the amp with only one MOSFET irfp264n per bank. Runs fine. There is clean sinewave at the output. Just waiting now for whole new batch of irfp264n.
i've recently repaired the same amp and replaced the 264N with FDH44N50 without problems and yes, IRFP264N are original part number.
I'm buying mostly from Farnell.
So there are IRFP264 but without the N as a suffix which looking at the datasheet are not quite what the IRFP264N are. I'm happy I still haven't ordered them.
So the closest and available ones i could find are FDA59N25 or IRFP4332Pbf and i'm leaning towards FDA59N25 due to more similar parameters with the 264n's.
So there are IRFP264 but without the N as a suffix which looking at the datasheet are not quite what the IRFP264N are. I'm happy I still haven't ordered them.
So the closest and available ones i could find are FDA59N25 or IRFP4332Pbf and i'm leaning towards FDA59N25 due to more similar parameters with the 264n's.
fda59n25 may seem ok, they are easier to drive, but they are a little too slow compared to the originals.
Many amps that use the same design, use FDA59N25 without problems, but the only sure thing you can do is try.
