PhilCs blog / the latest things hes broken(fixed)

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BennehBoy
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Re: PhilCs blog / the latest things hes broken(fixed)

Post by BennehBoy »

Were any of those 64 boards dead? I need a replacement CIA chip if you've got one going.

Bit OT, but I'm currently diagnosing the faults on a 1541 that I picked up as spares or repair, so far I've found 3 failed CMOS chips (2 are MOS fab), and it looks like one of the VIA's is dead. Should I start up a project thread? It would never have any ST stuff in as I've only got Commodore gear.
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PhilC
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Re: PhilCs blog / the latest things hes broken(fixed)

Post by PhilC »

@BennehBoy yes do start up a project thread, we are happy to see all kinds of retro gear here.

I have two old type long board C64 motherboards which don't work but I never got round to seeing why. Which chip is the CIA you need? (only just started with the C64 stuff)

Alternatively I have a fully working and recapped C64C board which has been set up to take a 6581 SID but I'd want £55 for that.
If it ain't broke, test it to Destruction.
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stephen_usher
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Re: PhilCs blog / the latest things hes broken(fixed)

Post by stephen_usher »

bigbloke wrote: Wed Nov 10, 2021 1:41 pm
rubber_jonnie wrote: Wed Nov 10, 2021 1:13 pm My Dreamcast was new, and I don't have any fluorescent lighting, though I suppose it may have been exposed in the factory and then exposed later as you suggest.

I think it's a much more complex scenario though, with a lot more factors involved.
My Dreamcast is exactly the same. It looks worse than most of the youtube before and after ones, yet I have treated the thing with kid gloves as they say.

As I understand it the yellowing is caused by bromides in the plastic - used to make it more fire retardant IIRC - and I remember a bromine test at school (far too many years ago!) which showed it as quite an "active" chemical. So I guess it is coming out of the plastic, and not being "burnt off" by sunlight/UV as well as being more mobile when in sunlight. So lose-lose both ways. Leave it in sunlight and it speeds up the action of yellowing, but it will happen anyway through time. My list of items that need "retro-briting" is now longer than we have sunny days for!
Another (potentially dangerous if you don't get the temperature just right, i.e. 60C) is heat retrobrighting using warmed peroxide solution (such as concentrated OxiClean). It uses thermal activation of the reaction rather than UV. The problem is that the chemistry starts at a temperature close to the softening temperature of ABS plastic, so you need a very accurate thermostat and constant circulation of the peroxide solution.
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.
BennehBoy
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Re: PhilCs blog / the latest things hes broken(fixed)

Post by BennehBoy »

PhilC wrote: Wed Nov 10, 2021 3:44 pm Which chip is the CIA you need? (only just started with the C64 stuff)
It's the 6526.
PhilC wrote: Wed Nov 10, 2021 3:44 pm Alternatively I have a fully working and recapped C64C board which has been set up to take a 6581 SID but I'd want £55 for that.
I just need that chip tbh, I've got 2 C64's here, a breadbin one that I've added a quad rom switcher to (using an Arduino Nano & colour led - cycle roms by holding down Restore key), and a C64C which is way more robust but just not as nostalgic as the breadbin. Both have genuine SID's, early type in the breadbin & late in the C64C. I've given away a couple of other machines.

I have an Ultimate 1541 II+ that I use with them, but it's also just 'fun' to use them with real floppies, so I have 2 1541's. One which has Dolphin DOS - a parallel hardware upgrade and is lightning fast, and this latest one which I'm slowly working through fixing the faults on. I've socketed and tested almost all the CMOS chips so far, 3 had failed, but suspect the 9602 that controls the stepper motor is a duffer - awaiting parts to land.

I managed to blow the CIA on the breadbin whilst trying to fault find this new drive - accidentally hotplugged the serial cable, the CIA is not forgiving of that at all - there's probably a simple way to build an isolator, just more time.
BennehBoy
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Re: PhilCs blog / the latest things hes broken(fixed)

Post by BennehBoy »

I've managed to source a CIA now mate - so don't knock yourself out trying to test one from that duff board. Cheers.
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PhilC
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Re: PhilCs blog / the latest things hes broken(fixed)

Post by PhilC »

BennehBoy wrote: Fri Nov 12, 2021 11:38 am I've managed to source a CIA now mate - so don't knock yourself out trying to test one from that duff board. Cheers.
Ok cool. I was going to desolder and test at the weekend. I'll probably still do that at some point.

Good luck with the C64.
If it ain't broke, test it to Destruction.
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PhilC
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Re: PhilCs blog / the latest things hes broken(fixed)

Post by PhilC »

Don't you just love it when the computer you set up and all was working great when you turned it last week.

Then when you switch it on today and it leaks magic black smoke from the motherboard.

Time to find another HP ML350 G6 motherboard from ebay then.

I wouldn't mind but I'd set it up with a shed load of ram, hds, etc and it was going to make a good old workhorse desktop computer, well at least it did for a week.
If it ain't broke, test it to Destruction.
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Re: PhilCs blog / the latest things hes broken(fixed)

Post by exxos »

What went up ?

Turn on surges are not good for power supplies as they are essentially powering up into a short circuit which is why stuff blowing up tends to come from. This is why my PSUs have a current limited softstart. Maybe I should look into PSUs for other things at some point..
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
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viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
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Re: PhilCs blog / the latest things hes broken(fixed)

Post by rubber_jonnie »

Damn.

You know we need photos right? No chance of a repair at all?
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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
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PhilC
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Re: PhilCs blog / the latest things hes broken(fixed)

Post by PhilC »

@exxos @rubber_jonnie the chip is unrecognisable that blew and then there was also smoke from under the heatsink of the main chip for the intel chipset. So unfortunately not an easy repair if it was possible to even get the parts.

I managed to snag another motherboard for £15 plus postage though and also a couple more servers for peanuts, so once it's up and running again it'll be maxed out on ram etc. Why do I need all that ram? Why not? :lol: I think the max is 192gb or something daft like that. It was 96gb before it blew up and then just used 4 - 10%
If it ain't broke, test it to Destruction.
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