KevinE Posted December 17, 2012 Share Posted December 17, 2012 Got an FDS388 omnidrive here with a strange fault. Upon power-up the front panel goes through the self-test (ie chasing the leds in a pretty way)..but it does it all in super-slow motion..one led every 2 seconds or so. It's as though the CPU is running at the wrong clock speed. The LCD screen just flashes rubbish..probably about right in this sort of condition. I've changed the crystal and looked at the eprom which refused to verify, so I fitted a new one with the latest firmware. No change. The power rails (there's loads of 'em) all check spot-on. Theres evidence that the main system CPU has been changed at some point. All quick-fixes appreciated. B-) Link to comment Share on other sites More sharing options...
DrV Posted December 17, 2012 Share Posted December 17, 2012 Got an FDS388 omnidrive here with a strange fault. Upon power-up the front panel goes through the self-test (ie chasing the leds in a pretty way)..but it does it all in super-slow motion..one led every 2 seconds or so. It's as though the CPU is running at the wrong clock speed. The LCD screen just flashes rubbish..probably about right in this sort of condition. I've changed the crystal and looked at the eprom which refused to verify, so I fitted a new one with the latest firmware. No change. The power rails (there's loads of 'em) all check spot-on. Theres evidence that the main system CPU has been changed at some point. All quick-fixes appreciated. B-) Kevin, I'm not familiar with the kit you are talking about but, looking at it from a purely computing point of view - it might be worth checking that there isn't a problem with an interrupt line causing continuous interrupts (eg. held low or open circuit). This would slow the processor down even though the clock is running at the right frequency. Dave Link to comment Share on other sites More sharing options...
KevinE Posted December 18, 2012 Author Share Posted December 18, 2012 That's a point, though without a circuit diagram I'm all at sea. I'll disconnect the keyboard for a start in case its a button matrix problem.... Link to comment Share on other sites More sharing options...
KevinE Posted April 11, 2018 Author Share Posted April 11, 2018 A follow-up to this thread which I'd forgotten about and only found again after googling another 388 fault brought me here. Might help someone in a similar situation. I gave up on the 388 in question and advised the client send it to a well-known BSS repairer staffed from ex BSS/C-Audio employees.Unfortunately they couldn't find the fault either and scrapped it. Link to comment Share on other sites More sharing options...
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