Need schematic Technics SA-918

This is for a good customer who wants this toilet fixed for sentimental rea sons (so he says). It has a shorted STK4152II that's putting the -Vcc on t he speaker terminal on one side, the other side is working. There are no r elays of any kind in this receiver and I can't believe there isn't some sor t of speaker protection scheme incorporated, not even speaker fuses. Even Pioneer's suicide circuit was better than nothing at all.

Anyone have a schematic for this? Also, the STK4152 is a discontinued devi ce, but there are plenty out of Hong Kong. Anyone use one of these generic s recently and had good success with it?

Reply to
ohger1s
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I tend to use a pair of TDA7293 in these situations STK/TA hybrids,don't know specifially for that STK, bending up pins and rewiring in to suit. Sometimes you need to invert the mute line control though

Reply to
N_Cook

Those knockoff ICs are almost never good. Real NOS is hard to find.

I couldn't find the print on the receiver but the chip is only 30 WPC which means you can use a couple of LM3886s in it, just figure out how to remoun t, use the inverting and non-inverting, hook up the power and the speakers, and you need a resistor to the muting line. Get them clamped to the heatsi nk and you should be alright. I did that on a Mitsubishi X-11 system. I alm ost wanted to just put preamp outs on it and tell the guy to use an externa l amp but they put the tone controls in the output feedback so they would n ot work unless I got some OP AMPs and this was just a better solution. Just hook up the speakers and you are good to go.

Cook wants to rebend pins but what I did was to turn the upside down and si mply wire the pins to the board where needed. That way the pinout doesn't e ven have to come close. Ad the LM3886 is a six wires solution, and one of t hose is the muting and only requires like a ten K resistor which can easily do both channels. Don't even entertain the idea of leaving the working cha nnel in there. Too much PITA and for no good reason.

Reply to
jurb6006

On Wednesday, November 30, 2016 at 11:51:24 PM UTC-5, snipped-for-privacy@gmail.com wro te:

ch means you can use a couple of LM3886s in it, just figure out how to remo unt, use the inverting and non-inverting, hook up the power and the speaker s, and you need a resistor to the muting line. Get them clamped to the heat sink and you should be alright. I did that on a Mitsubishi X-11 system. I a lmost wanted to just put preamp outs on it and tell the guy to use an exter nal amp but they put the tone controls in the output feedback so they would not work unless I got some OP AMPs and this was just a better solution. Ju st hook up the speakers and you are good to go.

simply wire the pins to the board where needed. That way the pinout doesn't even have to come close. Ad the LM3886 is a six wires solution, and one of those is the muting and only requires like a ten K resistor which can easi ly do both channels. Don't even entertain the idea of leaving the working c hannel in there. Too much PITA and for no good reason.

LOL! I'm not going to invent the wheel on this thing; it's not worth time, sentimental reasons be damned. At the end of the day, I still have to bil l by the hour. A cheaper solution which I've used in the past is to buy co mplete used receiver on ebay for parts.

My questions were if anyone had successfully used the currently available S TKs and this indeed has no protection scheme (hence the request for the pri nt).

In any case, I'm sure one of the Nesda members has an OEM STK somewhere and I'll post a request there if I'm not confident one of the currently availa ble STKs are not suitable.

Thanks for the advice guys.

Reply to
ohger1s

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