Thankyou all so much for the replies. >> Q1) As I understand it, I just need to fit the 16 missing drams and >> decoupling caps? > >You also need the BASIC 256 ROMs, or the added 128k will not be used by >BASIC. >On startup, the kernal tests the installed RAM, but there is no feedback >how many RAM was found. >Even if RAM is faulty, there is no display. Thanks Christian. Makes the test rather pointless doesn't it... >> Q6) I think modern ATX supplies have now dropped the -12V rail. From >> looking at the schematics this is only used for the RS232 port. As I'm >> not likely to use this any time soon, will I have any issues if I omit >> the -12V rail? > > Or you look for an old AT supply. MikeS was correct, it was the -5V rail that had been dropped from the ATX specification. The -12V still exists. I've ordered a 150W ATX supply used for powering mini-itx boards. It'll supply about 4.2 watts on the 12V, which should be enough for the monitor. >> Q7) The CBM-II PSU's all supply a 50/60hz signal from the PSU, which I >> think is just used for the TOD clock on the CIA. As I'm unlikely to >> find this on a modern PSU, is there a really simple way of generating >> this signal? > > Yes, use an optocoupler. Wow - so many options. I like the option of a single chip solution from Gerrit as it doesn't require opening the PSU or attaching or hooking up to mains voltages. Incidently, the MAX machine used a 555 to generate the TOD signal, as Uz speculated. Rob Message was sent through the cbm-hackers mailing listReceived on 2012-02-16 18:00:12
Archive generated by hypermail 2.2.0.