Hi all,
I recently got hold of a non-working Amiga 1000 with Phoenix motherboard. The previous owner said it was working until he knocked a side RAM expansion.
I've tested most of the main chips in an A500 and found them to be faulty. I've replaced the CPU, CIAs, Paula, Denise and Gary with ones that seem to work. I've put in a different Agnus 8372A that I took from another non-working Amiga so I'm not certain it's good. (Can I test this by putting it in my A500 which currently has an 8371??)
It's currently giving no video signal. I've tested the Hsync and Vsync with a scope and they are both giving a flat 5V.
I'm probably a bit out of my depth. Hoping for suggestions about what I should be trying next?
Here is a more complete list of things I've tried...
- Removed floppy in case of shorts
- Removed rear RF shield in case of shorts
- Tested the PSU output... all good, Tick gives 50Hz
- Tested CPU, CIAs, Gary, Paula, Denise... all faulty and replaced.
- Replaced Agnus 8372A with another that us untested.
- No sound output on startup
- Caps lock lights up when power first applied then behaves normally toggling when pressed.
- Ran for a while and felt the chips...
- Warm to hot: CPU, Agnus, Paula, Denise
- Cool to warm: Gary and the CIAs
- Tried starting without kickstart roms - no effect
- Checked activity on Gary pin 21 on startup. I read that this might give an indication if the KS roms are being accessed. It goes straight to 5V and stays there. I'm not certain but I think it's not getting to loading the KS.
- Checked the reset pin on the CPU, sitting at 3.18V, didn't seem to change when I hit the Ctrl-Amiga-Amiga