I have Sundown SAM 500D with blown power supply fets and its drivers. The smd drivers were toasted so couldn’t read markings. This amplifier only uses a total of two drivers for both banks of FETS. One driver per side, as oppose to many designs were Fets are driven by two drivers (PNP and a NPN). This design also have a diode across each emitter and base of each driver (so am assuming thats why only one driver per side).
Amplifier uses a 494. Would MMBT3906 be suitable replacement? What diode to use? Am just a little confused on why it only uses one driver per side as oppose to two. Any help appreciated.
Also this amplifier uses a total of four FETs on the switching, two per side. I am using 3205’s with 68ohm gate resistor (the 47ohm resistors I had in stock were a bit too big in package size, hence why I used 68ohm).
Amplifier uses a 494. Would MMBT3906 be suitable replacement? What diode to use? Am just a little confused on why it only uses one driver per side as oppose to two. Any help appreciated.
Also this amplifier uses a total of four FETs on the switching, two per side. I am using 3205’s with 68ohm gate resistor (the 47ohm resistors I had in stock were a bit too big in package size, hence why I used 68ohm).
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At one time, Sundown would provide tech support. You may want to check with them.
I'd probably use an MMBTA56 and a 1N4148 type diode (you didn't indicate the diode package).
Cost is one consideration in most amplifiers.
I'd probably use an MMBTA56 and a 1N4148 type diode (you didn't indicate the diode package).
Cost is one consideration in most amplifiers.
I came up with this but it’s all really a guess, smd drivers were toast as well as the diode that was across E and B. Even orientation (direction of diode) is an assumption.
Thanks a bunch, that’s the schematic I was looking for. I went through several and all of them had pairs. I didn’t want to guess it and cause more damage or let the magic smoke out.
Don‘t think so, I can take pictures, but the whole board is covered in a thin layer of silicon from factory (like to water proof it).
Well don’t know how I missed it but the output FETs were shorted too, unless they weren’t and now are upon powering up. Am pretty sure they were good otherwise I would’ve removed them when I had to remove the whole sink with all devices mounted on it (transformer and caps didn’t allow me to remove the FETS).
Output FETS IRF3710
Output FETS IRF3710