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Mrbombermillzy's box of delights

Blogs & guides and tales of woo by forum members.
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mrbombermillzy
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Re: Mrbombermillzy's box of delights

Post by mrbombermillzy »

Crickey. :o

Youve almost gone full circle with this.

Its good know at least both CPUs are ok.

Lets see how you get on with the new 74HC373s.
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Re: Mrbombermillzy's box of delights

Post by rubber_jonnie »

OK, so things reached a point where I had to remove the mods and top socket from the PC Speed yesterday because I believed I could see PCB damage and I couldn't get to it, and sure enough there was:

IMG20250816160443.jpg
IMG20250816160443.jpg (269.26 KiB) Viewed 474 times

Can you spot the difference?

And here closer in:

IMG20250816160524.jpg
IMG20250816160524.jpg (261.38 KiB) Viewed 474 times

It was well hidden under the wiring for the mod, and a bit by the socket/pin header.

Screenshot 2025-08-17 at 09.01.25.png
Screenshot 2025-08-17 at 09.01.25.png (471.12 KiB) Viewed 474 times

It seems that some of the pads along the 68000 connector area were missing/damaged previously. I have installed new pin headers and fixed the missing track and the track that was cut for the mod.

However I need to buzz out everything once all repairs are complete as I can't help but think something else is astray in terms of the traces as it looks like the original pin header and socket installation did some damage, not to mention wondering if there is another cut track somewhere on the board.

I need to wait for the replacement 373's to arrive now before more testing so I can be sure all the parts are good. Hopefully they'll come in the week as this time next week I'll be on my way to France for my holidays and won't be able to do anything for a while.
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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rubber_jonnie
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Re: Mrbombermillzy's box of delights

Post by rubber_jonnie »

Interesting, the PC Speed remake comes up very cheap on JLCPCB, so I might order some when I get back from my holiday.
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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rubber_jonnie
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Re: Mrbombermillzy's box of delights

Post by rubber_jonnie »

OK, so @mrbombermillzy

Good news, the PC Speed is working:

IMG20250818101244.jpg
IMG20250818101244.jpg (215.23 KiB) Viewed 458 times

I did a little rework this morning where the pad was damaged, the 5th one in from the right with the missing pad:

IMG20250818101302.jpg
IMG20250818101302.jpg (289.31 KiB) Viewed 458 times

And it booted right away. What I'll do is send you the board back with a CPU/socket combo with it to ensure that it's kept stable during transport and to make it easy for you to plug straight into the CPU socket.

It is showing a little instability, so I'm going to add a bodge wire from the top to the track underneath to be 100% sure of s good connection.

:)
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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rubber_jonnie
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Re: Mrbombermillzy's box of delights

Post by rubber_jonnie »

More proof of life:

IMG20250818120106.jpg
IMG20250818120106.jpg (156.74 KiB) Viewed 454 times
IMG20250818120126.jpg
IMG20250818120126.jpg (417.29 KiB) Viewed 454 times
And I've put some conformal coating on the repairs:

IMG20250818120626.jpg
IMG20250818120626.jpg (325.17 KiB) Viewed 454 times

So after a bit of burn in testing, I can get this off the bench and make a start on the DTV's.
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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mrbombermillzy
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Re: Mrbombermillzy's box of delights

Post by mrbombermillzy »

That was an awesome fix Jon. Thank you. :cheers:
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Re: Mrbombermillzy's box of delights

Post by rubber_jonnie »

mrbombermillzy wrote: Mon Aug 18, 2025 1:45 pm That was an awesome fix Jon. Thank you. :cheers:
Not a problem :)
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...
User avatar
rubber_jonnie
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Posts: 15151
Joined: Thu Aug 17, 2017 7:40 pm
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Re: Mrbombermillzy's box of delights

Post by rubber_jonnie »

OK, so DTV no 1 is able to be powered on OK after fixing all the wires that fell off!!!

IMG20250818162224.jpg
IMG20250818162224.jpg (269.38 KiB) Viewed 438 times
IMG20250818162226.jpg
IMG20250818162226.jpg (317.79 KiB) Viewed 438 times

I haven't tested beyond that so far.

This is the device with various spaghetti tied to it for making it a 'real' C64. Now I know it's working I'll see what the other two are doing.
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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mrbombermillzy
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Re: Mrbombermillzy's box of delights

Post by mrbombermillzy »

rubber_jonnie wrote: Mon Aug 18, 2025 4:39 pm OK, so DTV no 1 is able to be powered on OK after fixing all the wires that fell off!!!
That was quite the problem really. I dont know if its a dirty board or what. Literally just the weight from the wire loom resting on a surface was enough to ping the wires off. :lol:
rubber_jonnie wrote: Mon Aug 18, 2025 4:39 pm Now I know it's working I'll see what the other two are doing.

The other two have just been stripped from the cases, so should be fine. I have supplied them for reference/spares and also for you to perhaps build yourself one. :)
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Re: Mrbombermillzy's box of delights

Post by rubber_jonnie »

mrbombermillzy wrote: Mon Aug 18, 2025 4:49 pm
That was quite the problem really. I dont know if its a dirty board or what. Literally just the weight from the wire loom resting on a surface was enough to ping the wires off. :lol:

The other two have just been stripped from the cases, so should be fine. I have supplied them for reference/spares and also for you to perhaps build yourself one. :)
So the wires in from the on off switch were not happy, I was cleaning up and some of the pads fell off, perhaps having been overheated previously. I've fixed that and hit it with hot glue for strain relief.

The rest of the wires for no1 seem good under the scope, though I did find some solder balls where you wouldn't want them, so have removed them. It really does need the positions checking over to be sure they are correct.

Also, for the SD2IEC, how are you supposed to get into that, presently it just goes into the built in stuff.

After a bit of wire fixing, no2 powers up fine, but it has far better visual quality than the modded one. I'll check number 3 later, but it seems to some wires hanging, so a bit more soldering required.

Weirdly it uses the LED to regulate the voltage to the board, though I'm sure it'd be happy to use 3.3v if fed directly.

If you're happy for me to keep one I certainly will :)
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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