BBC Model B & Acorn Electron

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Re: BBC Model B & Acorn Electron

Postby mrad01 on Mon Mar 18, 2013 5:01 pm

MisJiF wrote:If it has 6264 RAM chips on it, it will be a sideways RAM board. This can be used to load ROM images (files) into and is really useful as you don't need to replace a physical ROM everytime you want to run a different peice of ROM software. The switch is the write protect switch as some ROM images try to write back to themselves. They will not work if they detect they are in sideways RAM instead of a read only IC. Open the switch, load the ROM image and close the switch. This stops write backs and makes the ROM image think it's an actual ROM.

BBC PSUs are fiddly, but not too hard to fix and most issues are already documented.

Take a look here:
http://www.sprow.co.uk/bbc/howto.htm

Certainly ask on http://stardot.org.uk/forums/ if you have queries and check out this thread:
http://stardot.org.uk/forums/viewtopic.php?f=3&t=2190

I'm in Auckland if you need any help.

Cheers,

Mike.



Thanks Mike, I picked up replacement capacitors today and will fix the PSU tonight (hopefully) - then I can see how this thing works! Exciting.

We did have one of these at my school, but we were too busy hacking around inside Apple IIs to even give it a chance. Sad. Look far more advanced than the Apple II. I'm actually very impressed with the hardware for 1981.

I'll update once I have a running PSU...

BTW, any beginner info sites on using ROMs, loading ROMs etc?
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Re: BBC Model B & Acorn Electron

Postby tezza on Mon Mar 18, 2013 7:03 pm

Here is one source I had bookmarked.
http://www.stairwaytohell.com/index.html

The BBC Lives! is another one.
http://www.nvg.ntnu.no/bbc/
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Re: BBC Model B & Acorn Electron

Postby TRS80 on Mon Mar 18, 2013 8:41 pm

OK. These are 8K static RAM chips. Does the board fit into one of the ROM sockets?
Wanted: S-100 Bus components - please PM me if you have any. They don't even need to work!

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Re: BBC Model B & Acorn Electron

Postby mrad01 on Mon Mar 18, 2013 8:48 pm

TRS80 wrote:OK. These are 8K static RAM chips. Does the board fit into one of the ROM sockets?


Yes it does, and there are several wires going off the board to various chip pins on the logic board.
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Re: BBC Model B & Acorn Electron

Postby mrad01 on Mon Mar 18, 2013 11:29 pm

Well, got the PSU running and pumping out 5v on each of the pins. Nice.

Now I have a black screen (no prompts) and a weird hum from the speaker.Tried a few ideas from http://www.sprow.co.uk/bbc/doctor.htm#Diagnose - but running out of awake time...Zzzzzzz.

I'll reseat all the chips and see what I get - maybe remove the RAM/ROM sidewise card etc.

Fun!
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Re: BBC Model B & Acorn Electron

Postby MisJiF on Tue Mar 19, 2013 1:35 pm

BTW, any beginner info sites on using ROMs, loading ROMs etc?


The BBC Lives! and Stairway to Hell are bound to have loader programs for ther ROMs as well as the ROM image files themselves.
Sprow also has one called ROMLOAD but I've never tried it:
http://www.sprow.co.uk/bbc/bbconly.htm

Some games use the extra memory too for an exhanced experience. Repton 3, Elite and Strykers Run are 3 I can think of.

Cheers,

Mike.
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