slaanesh
Member
I recently bought a Macintosh Quadra 605 And completed the following work.
I checked the power supply and recapped it completely and it works like a champ rock steady voltages at the expected levels,
I recapped the board using tantalum caps. Everything seemed to go really well. No pads damaged and only a bit of cap goo mainly around the top-left part of the board. cleaned it thoroughly with loads of 99.9% IPA.
Anyway it doesn’t boot or even post. No chime or video. I’ve tried a known good CRT and adapter with LCD.
I’ve checked the speaker and it’s showing a good 16.2 ohms resistance which is spot on. I’ve checked the speaker out connector and the switch is working and should be routing to the internal speaker.
im starting it with fan, HD but no SIMMS at all just the onboard RAM. I’ve tried with and without the PRAM battery but no difference. I’ve pressed the CUDA button several times.
I’ve checked the power to the various caps and it all looks good. With my scope w I’ve checked the oscillator and it’s getting a good steady oscillation.
What I don’t see is any activity on the RAM. I’m wondering if the CPU is even getting out of reset state?
how to check? The MC88920 controls this state and I believe RST_IN and RST_OUT control this but the later is always low.
Attached is a photo of the board just before recapping.
Any suggestions?
I checked the power supply and recapped it completely and it works like a champ rock steady voltages at the expected levels,
I recapped the board using tantalum caps. Everything seemed to go really well. No pads damaged and only a bit of cap goo mainly around the top-left part of the board. cleaned it thoroughly with loads of 99.9% IPA.
Anyway it doesn’t boot or even post. No chime or video. I’ve tried a known good CRT and adapter with LCD.
I’ve checked the speaker and it’s showing a good 16.2 ohms resistance which is spot on. I’ve checked the speaker out connector and the switch is working and should be routing to the internal speaker.
im starting it with fan, HD but no SIMMS at all just the onboard RAM. I’ve tried with and without the PRAM battery but no difference. I’ve pressed the CUDA button several times.
I’ve checked the power to the various caps and it all looks good. With my scope w I’ve checked the oscillator and it’s getting a good steady oscillation.
What I don’t see is any activity on the RAM. I’m wondering if the CPU is even getting out of reset state?
how to check? The MC88920 controls this state and I believe RST_IN and RST_OUT control this but the later is always low.
Attached is a photo of the board just before recapping.
Any suggestions?