I have an AGC AC1100-12 'TURBO BOARD' board that I've been tinkering on here and there, trying to get it working. It's CPU is a Sony CXQ70108D-8 which I understand is a V20 and I feel that it's original to the board. If the -8 on the CPU indicates 8 MHz then this would be a 50% overclocking. If this is an 8MHz rated CPU then... was such aggressive factory overclocking a thing? I think I'll pull the CPU and test it in a less intense environment.
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Sony CXQ70108D-8 (V20) CPU at 12MHz?
- Thread starter Dagwood
- Start date
Chuck(G)
25k Member
CerDIP CPU? Probably okay to run 12MHz. I've been running a 5MHz V20 at 9 MHz for years.
1ST1
Veteran Member
And I was not able to run a 8 Mhz V30 stable at 10 Mhz...
Chuck(G)
25k Member
So, YMMV. But what were the original support chips rated for?
At any rate, there's no shortage of the faster V20 CPUs.
At any rate, there's no shortage of the faster V20 CPUs.
3+ Years Later....
CPU tested good. No power rail shorts. U7 (74S175) was the hottest thing on the board at 150F so I replaced it and found a bunch of sand like debris under it. Now the board works. I think that sand is probably under all the chips because I found it under the socketed ones too. I forgot to test the old chip so I don't know if it was the issue or the debris. On this board that chip is part of the keyboard circuit. I know this because I spent some time troubleshooting a "BAD KEYBOARD" message to later discover the keyboard lock needs to be jumpered. So if your AGC AC1100-12 Turbo Board doesn't work and you haven't taken it to the beach lately then maybe check U7.
CPU tested good. No power rail shorts. U7 (74S175) was the hottest thing on the board at 150F so I replaced it and found a bunch of sand like debris under it. Now the board works. I think that sand is probably under all the chips because I found it under the socketed ones too. I forgot to test the old chip so I don't know if it was the issue or the debris. On this board that chip is part of the keyboard circuit. I know this because I spent some time troubleshooting a "BAD KEYBOARD" message to later discover the keyboard lock needs to be jumpered. So if your AGC AC1100-12 Turbo Board doesn't work and you haven't taken it to the beach lately then maybe check U7.