Luxman A-383 part 5

Luxman A-383 repair

Today i tried to get the switch chips to work with the gumstix and driver i wrote earlier (see part4) without success. All switches are to stay open! The ones i got are TC9163N instead of TC9163AN may that be the problem (negated inputs or so (hm, i should try that)). Unfortunately i can only find datasheets for AN and not for N.

I still have bypassed the switching and hooked up my speakers just to listen if the sound is ok anyway (only used test signals and headphones until now and square waves don’t make you happy).
Addition i forgot to add yesterday: I also can confirm now that an excessive load has been the cause of all the troubles. It blew the input and record switches. As a result that the CK and DATA lines of the input select have -14V on it. Which blew the CK line of the big fat luxman driver chip, hence the missing clock signal. Fortunately it didn’t seem to cause much more damage. There is one more thing though which i found out yesterday. If i select direct input, the overload protector relay clicks on for a 10 to 20 seconds after which it releases and everything seems fine again. But it indicates some bad somewhere which i need to look into.

Second addition: Just found out i stupidly enough ignored the chip select bits for the switch array. Adding a high for bit 11 did the trick. I uploaded a new and slightly improved driver here: TC9163.


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