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stephen_usher
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Re: General Stuff(tm)

Post by stephen_usher »

rubber_jonnie wrote: Sun Oct 11, 2026 9:25 am
stephen_usher wrote: Sun Oct 11, 2026 9:20 am
Putting a load on the power supply and looking at it using a scope showed that the output smoothing cap isn't doing its job any more and there's massive ripple.
Any chance you might be able to replace just that capacitor if the potting compound plays ball?

Though my temptation would be a full re-cap.
Unfortunately the PCB is the “right way up” so the PCB is on the bottom. All the potting compound will need to be removed or liquified to get it out of the case and access the components.
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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rubber_jonnie
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Re: General Stuff(tm)

Post by rubber_jonnie »

stephen_usher wrote: Sun Oct 11, 2026 10:50 am
rubber_jonnie wrote: Sun Oct 11, 2026 9:25 am

Any chance you might be able to replace just that capacitor if the potting compound plays ball?

Though my temptation would be a full re-cap.
Unfortunately the PCB is the “right way up” so the PCB is on the bottom. All the potting compound will need to be removed or liquified to get it out of the case and access the components.
I do so hate potting compound 😒
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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stephen_usher
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Re: General Stuff(tm)

Post by stephen_usher »

I think what I’m going to do is get a disposable baking tray and put the unit on stands so that the putty can run down into the tray and then bake it in the oven at about 100C and see if gravity can be my friend.

I can’t do that until at least tomorrow though.
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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PhilC
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Re: General Stuff(tm)

Post by PhilC »

I'll be looking on with interest as I've got a couple of PSUs with similar. The C64 ones might be different though as it looks like a resin.
If it ain't broke, test it to Destruction.
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