The strange case of the Commodore 64 colour bands.

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stephen_usher
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Re: The strange case of the Commodore 64 colour bands.

Post by stephen_usher »

Well, it's not the 74LS74... (Quick swap as I'd already socketed it.)

I'll do the 74LS193 later this evening.
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.
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Re: The strange case of the Commodore 64 colour bands.

Post by rubber_jonnie »

stephen_usher wrote: Thu May 12, 2022 5:55 pm Well, it's not the 74LS74... (Quick swap as I'd already socketed it.)

I'll do the 74LS193 later this evening.
Oh great, how annoying!!
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: The strange case of the Commodore 64 colour bands.

Post by stephen_usher »

And it's not the 74LS193.

Put in an order for an MC4044P from Retroleum.

That's the last chip. So if that doesn't solve the problem then nothing will. At least there's no more soldering as all the chips are in sockets now.
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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mrbombermillzy
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Re: The strange case of the Commodore 64 colour bands.

Post by mrbombermillzy »

:dizzy:

Well, I passed out from the stress of anticipation ages ago.

I wonder how you manage to deal with this so calmly?

Me and it seems @rubber_jonnie have been on the edge of our seats for a while now.
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Re: The strange case of the Commodore 64 colour bands.

Post by stephen_usher »

Well, it's just a case of following the most likely paths, one after another. Of course, Sod's Law states that it will have to be the very last thing that you can try which solves things.

Still, after this it's purely resistors and ceramic capacitors left, and it's unlikely to be those, so it would have to be a design flaw where a trace somewhere has a resonance at one of the harmonics of the PAL chroma frequency. Without some black magic analogue investigation that's not going to be fixable.
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.
stephen_usher
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Re: The strange case of the Commodore 64 colour bands.

Post by stephen_usher »

P.S. The only really frustrating bit is having to wait for the delivery of parts (and pay the massive postage and handling charges). It it were all off the shelf, pop into a shop I'd have gone through this process in a couple of days.
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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mrbombermillzy
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Re: The strange case of the Commodore 64 colour bands.

Post by mrbombermillzy »

I've got an RS warehouse fairly close (35 mins drive).

Is there not somewhere near you that may be a bit more pricey than online, but stock a good selection of components and get you out of a jam?

EDIT: Hey! I can add that to my event enticement list! :lol:
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Re: The strange case of the Commodore 64 colour bands.

Post by stephen_usher »

I don't know of any retail electronic component shops any more, with both Maplin and Tandy gone.
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: The strange case of the Commodore 64 colour bands.

Post by exxos »

stephen_usher wrote: Thu May 12, 2022 8:52 pm I don't know of any retail electronic component shops any more, with both Maplin and Tandy gone.
I think there's a few like rapid, ESR, Cricklewood etc...dotted about but only odd shops.
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viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
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rubber_jonnie
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Re: The strange case of the Commodore 64 colour bands.

Post by rubber_jonnie »

mrbombermillzy wrote: Thu May 12, 2022 7:50 pm :dizzy:

Well, I passed out from the stress of anticipation ages ago.

I wonder how you manage to deal with this so calmly?

Me and it seems @rubber_jonnie have been on the edge of our seats for a while now.
I just want to see it fixed, I love it when stuff gets fixed 😁
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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