Ok, so the IDE & RAM upgrade board has arrived so I will test that in the Rev 5 A500 soon (I hope).
@rubber_jonnie also kindly included a 27C400 EPROM so that I can program up a DIAGROM to see what the problem with the Rev 6 board is (green screen on boot).
The issue there is that I can't see an option for the specific 27C400 EPROM in the list for my TL866 programmer...
Some research required here I guess :roll:
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A500 - resurrection or pit of despair?
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rubber_jonnie
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Re: A500 - resurrection or pit of despair?
I just remembered I got one of these for my TL866:JezC wrote: 12 Feb 2026 17:18 Ok, so the IDE & RAM upgrade board has arrived so I will test that in the Rev 5 A500 soon (I hope).
@rubber_jonnie also kindly included a 27C400 EPROM so that I can program up a DIAGROM to see what the problem with the Rev 6 board is (green screen on boot).
The issue there is that I can't see an option for the specific 27C400 EPROM in the list for my TL866 programmer...
Some research required here I guess :roll:
I didn't end up using it because I used the BooBip ROM emulator instead...
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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...
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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JezC
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Re: A500 - resurrection or pit of despair?
Ah, thanks for the info. I may look up the details of the PCB and bodge together and equivalent... otherwise I can see it taking a week or so to get one ordered and delivered!rubber_jonnie wrote: 12 Feb 2026 17:42I just remembered I got one of these for my TL866:JezC wrote: 12 Feb 2026 17:18 Ok, so the IDE & RAM upgrade board has arrived so I will test that in the Rev 5 A500 soon (I hope).
@rubber_jonnie also kindly included a 27C400 EPROM so that I can program up a DIAGROM to see what the problem with the Rev 6 board is (green screen on boot).
The issue there is that I can't see an option for the specific 27C400 EPROM in the list for my TL866 programmer...
Some research required here I guess :roll:
I didn't end up using it because I used the BooBip ROM emulator instead...
My backup plan is to check on the vintage programmers in the garage and see if they can program this chip...
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rubber_jonnie
- Site Admin

- Posts: 14594
- Joined: 17 Aug 2017 19:40
- Location: Essex
Re: A500 - resurrection or pit of despair?
No worries and good luck!JezC wrote: 12 Feb 2026 21:12Ah, thanks for the info. I may look up the details of the PCB and bodge together and equivalent... otherwise I can see it taking a week or so to get one ordered and delivered!rubber_jonnie wrote: 12 Feb 2026 17:42
I just remembered I got one of these for my TL866:
I didn't end up using it because I used the BooBip ROM emulator instead...
My backup plan is to check on the vintage programmers in the garage and see if they can program this chip...
Sorry I should have thought of it earlier, but the BooBip caught me off guard with it's lovely USBness...
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...
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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JezC
- Posts: 2768
- Joined: 28 Aug 2017 23:44
Re: A500 - resurrection or pit of despair?
Thanks - I might not get chance to dig into this until later in the weekend as my son is coming back from university today & staying for the weekend, so unlikely to get much time for retro stuff today.rubber_jonnie wrote: 12 Feb 2026 21:16No worries and good luck!JezC wrote: 12 Feb 2026 21:12
Ah, thanks for the info. I may look up the details of the PCB and bodge together and equivalent... otherwise I can see it taking a week or so to get one ordered and delivered!
My backup plan is to check on the vintage programmers in the garage and see if they can program this chip...
No worries - I'd love one of those, shame they're no longer being manufactured!Sorry I should have thought of it earlier, but the BooBip caught me off guard with it's lovely USBness...
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rubber_jonnie
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- Posts: 14594
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- Location: Essex
Re: A500 - resurrection or pit of despair?
Have a nice weekend with your family :)JezC wrote: 13 Feb 2026 09:27 Thanks - I might not get chance to dig into this until later in the weekend as my son is coming back from university today & staying for the weekend, so unlikely to get much time for retro stuff today.
Yeah it is, though I think I sen you a link for an alternative, though not particularly cheap if you only have limited use for them.JezC wrote: 13 Feb 2026 09:27 No worries - I'd love one of those, shame they're no longer being manufactured!
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...
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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JezC
- Posts: 2768
- Joined: 28 Aug 2017 23:44
Re: A500 - resurrection or pit of despair?
Thanks!rubber_jonnie wrote: 13 Feb 2026 09:41Have a nice weekend with your family :)JezC wrote: 13 Feb 2026 09:27 Thanks - I might not get chance to dig into this until later in the weekend as my son is coming back from university today & staying for the weekend, so unlikely to get much time for retro stuff today.
Yes, you did...but as you say a bit pricey for a 'single use' but I'll see how the adapter options work out as an alternative.rubber_jonnie wrote: 13 Feb 2026 09:41Yeah it is, though I think I sen you a link for an alternative, though not particularly cheap if you only have limited use for them.JezC wrote: 13 Feb 2026 09:27 No worries - I'd love one of those, shame they're no longer being manufactured!
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