Whoops, I did it again! VIC-20 on the way...

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rubber_jonnie
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Re: Whoops, I did it again! VIC-20 on the way...

Post by rubber_jonnie »

Hmm, interesting:

IMG_20220216_142552.jpg
IMG_20220216_142552.jpg (529.91 KiB) Viewed 2191 times

Very nice work here, I suspect it's factory, but don't know enough to say what it's for. I'm guessing to replace missing or bad tracks on this version of mobo.
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stephen_usher
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Re: Whoops, I did it again! VIC-20 on the way...

Post by stephen_usher »

Seems to be using a few unused OR and NOT gates on the '02 and '04.

I can't see any references to those bodges on-line.
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Re: Whoops, I did it again! VIC-20 on the way...

Post by rubber_jonnie »

stephen_usher wrote: Wed Feb 16, 2022 2:58 pm Seems to be using a few unused OR and NOT gates on the '02 and '04.

I can't see any references to those bodges on-line.
It does seem to be, yes. Will have a look later too, see if I can find anything, Makes you wonder if some tracks were missed out.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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Re: Whoops, I did it again! VIC-20 on the way...

Post by stephen_usher »

I think I have an answer...

From what I've just read Commodore used larger RAM chips than was required as they had an over-stock, so I think this mod is trying to use the upper half of the RAM chips as a memory expansion. However, this was from Stack Exchange so it's probably wrong.
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
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Re: Whoops, I did it again! VIC-20 on the way...

Post by rubber_jonnie »

stephen_usher wrote: Wed Feb 16, 2022 3:02 pm I think I have an answer...

From what I've just read Commodore used larger RAM chips than was required as they had an over-stock, so I think this mod is trying to use the upper half of the RAM chips as a memory expansion. However, this was from Stack Exchange so it's probably wrong.
Interesting. I'm seeing only 3.5KB so it isn't using anything extra, or at least showing anything extra. Will dig more after work :)
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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Re: Whoops, I did it again! VIC-20 on the way...

Post by stephen_usher »

Can the VIC=20 basic see more than that? I don't think that it can.
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
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Re: Whoops, I did it again! VIC-20 on the way...

Post by stephen_usher »

I've just posted that picture elsewhere to see if they know what the mod is.
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
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Re: Whoops, I did it again! VIC-20 on the way...

Post by rubber_jonnie »

stephen_usher wrote: Wed Feb 16, 2022 3:18 pm Can the VIC=20 basic see more than that? I don't think that it can.
It can be expanded via the cartridge slot to 32KB from what I've read, though I will be looking at other internal options.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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Re: Whoops, I did it again! VIC-20 on the way...

Post by rubber_jonnie »

stephen_usher wrote: Wed Feb 16, 2022 3:23 pm I've just posted that picture elsewhere to see if they know what the mod is.
Cool thanks. I did the same.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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Re: Whoops, I did it again! VIC-20 on the way...

Post by stephen_usher »

Looks similar to this: http://www.sdiy.org/richardc64/vic20/vic01.html
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
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