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Circuit drawings for newer RiscPCs / Audio problem?

Posted: Tue Jan 02, 2018 8:59 pm
by gazzaD
I've recently acquired a RiscPC that is silent, apart from the odd crackle from the speaker. I've got as far as scoping out the bit clock, data and word select into the DAC (IC37) which look as I'd expect, but the left and right outputs are stuck at about 5.75 volts and not responding to the audio data. There has been some moderate battery leakage, which has got as far north as IC34. I'm fairly sure I have removed the contamination when replacing the battery, but without the correct drawings it's getting difficult to work out what should be going where,

Does anyone know where I can find the circuit drawings for the newer RiscPC motherboards that have the integrated 16bit sound? Or if anyone has come across this issue before suggestions are welcome?


Re: Circuit drawings for newer RiscPCs / Audio problem?

Posted: Sat Jan 27, 2018 2:45 pm
by opsy
Hi Gareth,
I haven't been able to find a circuit diagram for the issue 2 rpc. I've also lost internal sound. I'm sure mine is battery damage. By half inserting the audio out the internal speaker gave poor quality sound. So I replaced the socket only to find out that the mobile phone head phones have different connections.
Cheers Keith