I'd been trying to fix a quasi-complementary paralleled 4 device output, 400 W amp which probably babies the 2sd424's. After tremendous amount of work, perplexity, and smoke (the kind with acetylene-like puffs of carbon!), I finally decided to actually test the last couple of 424's I had.
Oh, they easily did 50 Watts at 6.5 amps, alright. But then I put 120 volts across one, and couldn't get past around 150 mA before it blew the 3 A fuse I had on it!
It shorted.
They read Toshiba 2sd424; a little alcohol took the print off very easily. I notice some high-power TO-3 's have rather thin mounting bases: the bases on these were quite thick, but all-steel construction. I guess they could have been 2N3055's.
Does anyone have suggestions what to tell the supplier when I inform them of their product? Has anyone gotten money back for this type of thing?
I'm interested in any comments on how to try to avoid counterfeit transistors, and what to do about it when you do get some.
Oh, they easily did 50 Watts at 6.5 amps, alright. But then I put 120 volts across one, and couldn't get past around 150 mA before it blew the 3 A fuse I had on it!
It shorted.
They read Toshiba 2sd424; a little alcohol took the print off very easily. I notice some high-power TO-3 's have rather thin mounting bases: the bases on these were quite thick, but all-steel construction. I guess they could have been 2N3055's.
Does anyone have suggestions what to tell the supplier when I inform them of their product? Has anyone gotten money back for this type of thing?
I'm interested in any comments on how to try to avoid counterfeit transistors, and what to do about it when you do get some.
Fake Counterfeit 2SB554 and 2SD424 Power Transistors
I am an older experienced service tech. I have an Adcom GFA-555 amplifier that one 2SD424 failed on an amp channel. I won't replace just one device (I believe it will be unbalanced and fail eventually). So, I found the 2SB554 and 2SD424 from an eBay seller in China and ordered a new set of transistors. Guess what? They failed in about a millisecond, no load, no nothin, just the voltage swing killed/shorted 7 of 8 of them. Just want you all to know that now I am replacing those transistors with a new set of ON MJ15024G / MJ15025G. I ordered them from Mouser. THESE must be true NON-COUNTERFEIT parts! Even these transistors are available from China, obvious more counterfeit parts. Just thought I'd throw in my 2 cents worth. Any other ideas out there? Oh yeah, I'm applying for a refund from the China eBay seller.
I am an older experienced service tech. I have an Adcom GFA-555 amplifier that one 2SD424 failed on an amp channel. I won't replace just one device (I believe it will be unbalanced and fail eventually). So, I found the 2SB554 and 2SD424 from an eBay seller in China and ordered a new set of transistors. Guess what? They failed in about a millisecond, no load, no nothin, just the voltage swing killed/shorted 7 of 8 of them. Just want you all to know that now I am replacing those transistors with a new set of ON MJ15024G / MJ15025G. I ordered them from Mouser. THESE must be true NON-COUNTERFEIT parts! Even these transistors are available from China, obvious more counterfeit parts. Just thought I'd throw in my 2 cents worth. Any other ideas out there? Oh yeah, I'm applying for a refund from the China eBay seller.
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