Thanks, I will look into replacing the RAM then I guess.

Do you happen to know at what point in the boot process the chirping noise is initialised? Because now it doesn't chirp so I guess this could be a good diagnostic marker.

Hi, Thanks for your reply, I ended up finding someone locally so I got the chips already. Installed them, system booted to basic 4.0 prompt! Only showed 32k of memory though, then I had to turn it off (as mentioned earlier in this post, I still haven't fixed the CRT so it switches itself off after a...

Hi, Made a little bit of progress with this. I installed both the BASIC and Kernal ROMs, but I still get the ML monitor when I boot it up, albeit with different values: https://i.imgur.com/SKu8mH3.jpg b# pc irq sr ac xr yr sp .; c6b9 e455 30 a4 16 20 f6 . I have however realised that there are 2 oth...

Thanks for your reply; I've found a replacement Kernal ROM online too, I'll try this if the BASIC one doesn't work alone.

Cheers,

Greg

That's great, thanks for your help. I found the corresponding ROM on ebay quite cheap. It's soldered in so I ordered some sockets too in case I have to remove it more than once. The next problem may be more difficult to solve though: the CRT only stays on for 2-3 minutes before fading/squashing down...

Hi, Thanks!, I've always wanted a PET of some description and this is the one that I ended up with. Very pleased. Here's the result of the command: .m c5b0,c5b9 .: c5b0 a0 20 c4 40 80 00 80 20 .: c5b8 00 35 01 50 00 40 a0 7f It might be worth noting that one of the option ROM slots (UD12) is occupie...

Hi, I just got myself one of these machines and it boots to what appears to be the machine code monitor: http://i.imgur.com/mKdHtpS.jpg The text in the image (for search engines) is: b# pc irq sr ac xr yr sp .; c5b9 e455 31 a4 16 20 f6 . I've heard that this could be symptomatic of a corrupt BASIC R...

Hi, I have one of these machines arriving soon from an online auction. The pictures show it working, but I want to be as careful as possible with it. I recently bought a BBC Micro, and after running it for a couple of hours, 2 capacitors blew in the power supply, these apparently are more or less gu...