Cheap n cheerful PSU fix ?

[ViperSan]

I have a good few of the cream coloured wedge power supplies hanging around ..
..all of which are faulty .
BUT ..It is almost always the crappy 5v rail which fails ..
The transformer is usually just fine ..
So
I opened one up ...to reveal the pcb charred and the regulater which is epoxied in ..also failed ..
But having removed the damaged pcb ..a nice vacant pocket is available measuring approximately ..
6cm x 3cm x 3cm ..into which a small switch mode power supply might fit ?
leaving the transformer to supply the 9volt AC ..
Well lookee here ..
I found these on ebay..
http://www.ebay.co.uk/itm/AC-DC-Switchi ... 8cXqDZvyoQ


One in the list ..
this one ..
is about perfect to fit in this space

AC-DC 5V 2A Switching Power Supply Module DC Stabilivolt Power 100-240V

Product Introduction:
1.Input Voltage:100-240V 50-60Hz
2.Output Voltage:5V
3.Output Current:2A
4.Size:6.1*3.6*1.9cm

Function:
1.Overvoltage Protection
2.Overcurrent Protection
3.Short Circuit Protection

and at £2 each delivered ..
..got to be worth a punt..
I've ordered 4 ..
Just got to wait now..
I'll let you know if it does the trick..
rgds
VS

[eslapion]

@ViperSan
These converters don't appear to be UL or CSA or ETL listed or registered. This means if they cause an electrical or fire hazard, you may not be covered by insurance.

Also, inexpensive switching PSUs tend to generate a lot of ripple on their output. Even if they pose no safety hazard at all, they could damage the equipment they power.

A few years ago, there were 'fake' iPhone chargers on the market and they posed no more safety hazard than any other chargers but what came out, when examined with an oscilloscope, was really total junk. (I vaguely remember a 350kHz ripple of more than 400mV).

[mrr19121970]

I did this. After about 12th use it went pop fizz and that was the end.

https://www.forum64.de/index.php?thread ... r-pimping/

[ViperSan]

Right idea I guess ..poor choice of switching psu ..
I guess I _could_ make my own ..
Or perhaps someone knows of a better module that will fit in that space ?
rgds
VS

[norm8332]

I did this and I just used a power adapter of known quality (from a Samsung phone charger) that was UL listed, just wouldn't use the unknown Chinese power supply. It works fine, Ripple was low but i also added a 2200 uf cap on the output.

[eslapion]

Right idea I guess ..poor choice of switching psu ..
I guess I _could_ make my own ..
Or perhaps someone knows of a better module that will fit in that space ?
rgds
VS

See : http://www.ebay.co.uk/itm/191676922882

More expensive... more quality. This one is UL registered and CE but there are many others.

[ViperSan]

Right idea I guess ..poor choice of switching psu ..
I guess I _could_ make my own ..
Or perhaps someone knows of a better module that will fit in that space ?
rgds
VS

See : http://www.ebay.co.uk/itm/191676922882

More expensive... more quality. This one is UL registered and CE but there are many others.

Nice unit and worth the extra ...but a very close call ..size wise ..
I'll give it consideration though..

On a different note ..
I repaired another C64 (black screen)
This one took some finding with multiple failures ..
Char rom ..
PLA
A memory chip ..
Plus a CIA
I suspect this has had catastrophic psu failure at some point ..
Nonetheless ..it is now functional.
I had all the chips I needed but for a 6526
Still using one borrowed from a working C64...for the purposes of soak testing ..
Remarkably the VICII and SID were OK.
I have used all my stock of CIA chips now ..
..but hard to get hold of these days.

On the plus side ..this REV C 1983 unit from a car boot sale ...is 90% socketed..
rgds
VS