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Re: BBC Model B No2. Will it live again!

Posted: 16 May 2021 22:15
by PhilC
@rubber_jonnie what do you need burnt to eprom? I've probably got some 27c128 around here somewhere.

Re: BBC Model B No2. Will it live again!

Posted: 16 May 2021 23:07
by rubber_jonnie
@stephen_usher @PhilC

@BennehBoy has sent me a PM offering to do it, so thanks both so much, but I should be OK.

I'll just go off and find the necessary ROM file for the OS and another for Tricky's diag ROM.

IC 43 change made no difference.

Also looking to pick up another, working this time:)

Re: BBC Model B No2. Will it live again!

Posted: 16 May 2021 23:17
by stephen_usher
Buying a working machine?! Where's the fun in that? :lol:

Re: BBC Model B No2. Will it live again!

Posted: 16 May 2021 23:59
by rubber_jonnie
stephen_usher wrote: 16 May 2021 23:17 Buying a working machine?! Where's the fun in that? :lol:
I know.....

Re: BBC Model B No2. Will it live again!

Posted: 17 May 2021 01:24
by Tomswork
Do you have a good 6502 the mostek chips were lemons 🍋

Tom

Re: BBC Model B No2. Will it live again!

Posted: 17 May 2021 08:50
by rubber_jonnie
Tomswork wrote: 17 May 2021 01:24 Do you have a good 6502 the mostek chips were lemons 🍋

Tom
Yes, and swapping it out makes no difference. Neither does swapping out the 6522 or booting in minimal config.

Re: BBC Model B No2. Will it live again!

Posted: 17 May 2021 09:27
by stephen_usher
Well, as discussed on Stardot, the minimal config won't boot with the standard ROM anyway.

Re: BBC Model B No2. Will it live again!

Posted: 17 May 2021 10:05
by rubber_jonnie
stephen_usher wrote: 17 May 2021 09:27 Well, as discussed on Stardot, the minimal config won't boot with the standard ROM anyway.
Oh, it won't? I missed that somewhere along the line!!

I'd better go back and re-read, thanks.

Re: BBC Model B No2. Will it live again!

Posted: 17 May 2021 10:10
by stephen_usher
By the way, with your minimal oscilloscpe do you see any activity on the address or data lines at the ROM socket when you switch on (with the CPU in, of course)?

Re: BBC Model B No2. Will it live again!

Posted: 17 May 2021 11:18
by rubber_jonnie
stephen_usher wrote: 17 May 2021 10:10 By the way, with your minimal oscilloscpe do you see any activity on the address or data lines at the ROM socket when you switch on (with the CPU in, of course)?
I do as it happens, so I do think something is happening and it's trying to boot.

I hopefully have some ROMs on the way to test with courtesy of @BennehBoy soon.