So I am repairing a SONY TA-FB930R, which has a blown MOSFET (Toshiba 2SK1529-Y). As usual, the amp has a second MOSFET for the other half of the signal (2SJ200-Y). How important is it that when I replace the broken one, I also replace the J200 with one from a matched pair?
Finding replacements is tricky as it is (plenty of ebay listings, but it’s hard to tell which are scams (wildly varying prices make me paranoid), and just because they sell 1529 and J200 in pairs does not mean matched…).
(I understand the next question is a dicey one, but Digikey doesn’t sell the above-mentioned MOSFETs, they’re only available used or NOS). Is there a reputable place that sells stuff like this actually matched?
Greetings,
“Important” is a somewhat subjective term… So far as it pertains to servicing old equipment, the matching of similar components will likely have lesser impact on the outcome as one’s ability to make any needful post-replacement adjustments and properly identify/correct any collateral damage incurred during the course of failure.
None that I’m aware, though definitions of “reputable” may vary. Once parts go out of production and the option of sourcing via manufacturer-authorized channels dissipates, the remaining secondary-market options are all subject to varying degrees of doubt.
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Thank you for your reply, Rick.
Naturally, I will do the usual bias current adjustment as per the service manual after replacing the MOSFET. I have found a vendor that says they will find a matching 1529 for me if I can give them the data of the currently working bits, so I am in the process of getting said data (hFE, Vbe etc).
Naturally, I will have a long squint at the circuit diagram to find components that may have become collateral damage and test&replace as needed. Thankfully, the PCB is not super cramped (and the case has a bottom lid for access without removing the PCB from the case).
As for reputation, I figured that there’s just so much one can do without a bit of trust and a “skip of faith”. I will take up the vendor I mentioned on their offer. At worst, I am out 25 bucks or so for a component I have no use for.
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