Dredging up an old thread of mine.

This is one of the "dead" units that I acquired from another BBS denizen once upon a time ago.

It worked for me here for a while after the "fix" described above here, but then stopped working, giving tons of I2C errors at boot.

Lately I have been using it to trace circuitry while repairing other units, and now that all of my other players are working well, I figured I'd tackle this one again.

Using the LogicPort analyzer on the I2C revealed that the CPU was sending correct data to the DSP, but the DSP was not ACKing the packets. I then hooked the analyzer up to the DSP oscillator circuitry -- pin5 of the nearby 74LVX74 chip, and discovered NO CLOCK.

Which is odd, because the DSP clock circuit is quite simple on this board. There's just a clock IN, and a clock OUT on the DSP, and then a crystal and the dual flipflop (the 74LVX74).

Oh, wait, there's also a clock POWER pin on the DSP. Mmm.. 0V.. that could be a problem. I tracked this back to where it originates, and that's the working 3.3V supply. So not that.

In desperation/inspiration, I took my trusty soldering iron to the clock POWER pad on the DSP (pin 65), and then also touched up the feeder coil pads (silver can thing, near the far edge of the board beside the SA1100), and then checked the clock again.

Woo-hoo! Nice little square-waves on the LogicPort display now. So I plugged in a hard disk and listened to The Guess Who for a spell.

Now to reassemble it all and perhaps find a home for it.

Cheers