Asian power supply repair

[Alugard]

Thanks Tom, i really appreciate your help and patience

So,

1. between the power plug ends it reads OL. But I cut some insulation inside and measured continuity from power plugs to these spots and it is fine. see attached photo.
2. reads 1 ohm
3. reads 4 ohms

Regarding shorts: did I understand correctly that I need to put one probe on both pins? or one by one? If i do both pins on the right and on the left and put another probe on other pins or shield, it reads OL.

[Scouter3d]

Hi,

so it looks like you have an open primary winding...

Or the "heat-fuse" on the primary winding did burn thru...

either way, this is not an easy fix, as the heat fuse is placed deep inside the winding (at least on the ones i opend...)
You would need to completely disassemble the transformer metal-sheets and unwind/rewind the primary winding...

I personaly did this one time, you can look is up on my page here (you need to scroll down quite a bit)...
http://www.8bit-homecomputermuseum.at/r ... glish.html

Cheers, TOM:0)

[Alugard]

Yeah, that doesn't sound nice and easy. I checked your site and hardly I will be able to do the same. If we talk about 2 ac-ac transformers, can you guys advise where to buy these? I checked AliExpress briefly and see that all transformers there do not hold enough current... maybe i don't understand something though:

https://www.aliexpress.com/item/4000276 ... hLFOBj6M5w

on 9v it shows 0.1a and on 18v - 0.04a.

[Scouter3d]

Hi,

If you try to build a new PSU (and feel up to the job working with mains voltage...)

yes, the ones you linked from aliexpress are way to "weak"...

the last time i built a replacement PSU (for a TRS-80 Model 1) i used 2 transformers like these:
This one for the 9V 1A AC
https://www.reichelt.at/at/de/trafo-14v ... ol_0&nbc=1
(If you wire the output in parallel, is has enough amps...)

And this one should be ok for the 16V 250mA
https://www.reichelt.at/at/de/trafo-14v ... ol_1&nbc=1

This is a german orderpage, but maybe you find something similar located nearer to you

Cheers, TOM:0)

[Alugard]

Thanks, Tom. These do not look cheap though. Like this, the power supply will cost around 40 eur alone Let me see if i can find something cheaper in china maybe...

[Scouter3d]

Hi,
yes, sadly i have not found a cheap replacement...

for the 9V AC part you can reuse part of an old Commodore C64 PSU...
Or even adapt the internal Transformer of an old Commodore 1541 Floppy Drive (not the 1541-II) this "should" work for 9V and the 16V...

Another option (if you like to modify your Creativision) is to feed +5V, +12V and -5V (from an old PC-PSU) to the right spots on the motherboard, i think Kevgal posted his mod somewhere here on the forum...

Cheers, TOM:0)

[Alugard]

Right. I don't have many old computers, unfortunately, just a couple of Spectrums. Some models of MSX also used AC power adaptors if I remember correctly but these are rare and expensive as well. And such MSX models are not so hard to modify for 9 or 5v DC.
I don't want to mod Creativision this way either, I prefer to preserve the original components and appearance. I guess it has to wait better days for now until I find a suitable PSU

[Scouter3d]

Hi, i found two fitting cheaper Transformers (14€ total for both)...

https://www.reichelt.at/at/de/printtraf ... ol_0&nbc=1

https://www.reichelt.at/at/de/printtraf ... ol_5&nbc=1

Cheers, TOM:0)

[Alugard]

Hi, i found two fitting cheaper Transformers (14€ total for both)...

https://www.reichelt.at/at/de/printtraf ... ol_0&nbc=1

https://www.reichelt.at/at/de/printtraf ... ol_5&nbc=1

Cheers, TOM:0)

Thanks, Tom! Let me search for something similar here in Singapore or China.