I've been Coleco'd

[rubber_jonnie]

Well turns out my other PSU doesn't have - 5v either

But I did win the Colecovison controller I was bidding on eBay

[stephen_usher]

You need an AT power supply not one of those new fangled ATX jobbies.

[rubber_jonnie]

You need an AT power supply not one of those new fangled ATX jobbies.

It would seem to be the case, yes, no -5v on those ATX PSUs, both missing that line entirely and I simply don't have an AT supply that I can access easily. I suspect I'd get more traction with a 20 pin ATX, they seem to retain the -5v.

In addition, the Meanwell RPT-60A that I used for my A5000 seems to have shot up in price ridiculously enough that I don't want to buy one, and that has everything I need, but it would mean completely disassembling the A5000...

I did have a thought though, the BBC B PSU runs at 5v and -5v, and I could use one of those with a bench PSU at 12v to get what I need and I can get at a BBC B easier than the A5000. Hmm, what can I do until my ColUSB arrives.

[rubber_jonnie]

Well, both the Coleco Joystick and the PSU have both shipped

In the meantime I have some galvanising paint due tomorrow so I can get the RF shield cleaned up and looking nice again.

I think I also need to look for a suitable AT PSU that will let me have a basic bench PSU for when I need weird voltages like -5v. Time for a scout round eBay...

[rubber_jonnie]

Just had a facepalm moment. I have a spare Electron PSU that delivers 5v, -5v and if I combine that with a bench PSU at 12v I'll have all of the voltages I need.

[HigashiJun]

Nice, your project is progressing step by step...

Hmm, reminds me of NKOTB.



https://www.youtube.com/watch?guid=ON&g ... pp=desktop

[rubber_jonnie]

Nice, your project is progressing step by step...

Hmm, reminds me of NKOTB.



https://www.youtube.com/watch?guid=ON&g ... pp=desktop

Indeed it is

NKOTB seems like a very long time ago to me!!

But I have proof of life:

IMG20240930105229.jpg (323.15 KiB) Viewed 37 times

IMG20240930105118.jpg (330.13 KiB) Viewed 37 times

So it's mostly working. The weird on screen stuff could be that the voltages are not quite up to snuff so I do still need the proper PSU that's ordered. Of course it's 4116 RAM so there may be issues with that too.

Happy with what I'm seeing so far though.

[HigashiJun]

Ah, such a nostalgic screen !

And the proof of life is evident.

A here comes a new machine in your personal museum

[rubber_jonnie]

Ah, such a nostalgic screen !

And the proof of life is evident.

A here comes a new machine in your personal museum

Indeed it does

It looks like both cartridges work as well

However, I left it running for a while and gave it the once over with my thermal camera. Aside from the CPU, most ICs were running quite cool, however the RAM looks off:

20240930-112839.jpg (11.58 KiB) Viewed 32 times

Clearly this is two banks of 4 RAM IC's and one of the 8 IC's is stone cold. The 3 voltages are present, so -5v on pin 1, 12v on pin 8 and 5v on pin 9, but my feeling is that with it being cold, it is probably dead, which probably accounts for the on screen corruption.

I think to be sure it's not a power issue, I'll add 5v from my 2nd bench PSU so the Electron PSU just has to deal with the -5v.

[HigashiJun]

@rubber_jonnie

Ouch, quite hot for 4116 RAM...

Better to fit heatsinks or maybe replace them with 4164 RAM for reliability ?