Removing epoxy from A600/A1200 PSU?

[8bitbubsy]

My A1200 PSU measures (under load) +5v (+5v rail), -12v (-12v rail), +5v (+12v rail)

This is nonsense, and it makes the Amiga sound "cut off" and weird. I thought I would open the PSU and change its capacitors and maybe its voltage regulators, but of course the whole PSU is filled with epoxy!!
I want to have that PSU because it's the only one I have, it's portable and it doesn't have a fan (= not noisy).

So today I ask: Is there any good method for removing all of the epoxy? It sits like glue.
I guess I can forget it, but I just wanted to ask just in case.

[Loedown]

Unless you can use some form of chemical that will eat the epoxy away but leave the circuit and components intact, it's binworthy.

[ChrisUnionNJ]

I have never seen a amiga PSU with epoxy filled I thought they only did that
with the 8 bit computers..

Chris

[ajk]

Bin it... you could only remove the epoxy mechanically. Might be worthwhile to save the PSU cable with the connector though, you can't get those kinds of plugs almost anywhere nowadays.

[Allen1]

I have one of those power supplies too and it is also failing. It was hard opening the case on mine as the base had been glued and I ended up with 3 of the 5 pegs on the base snapping off and staying in the resin. The suggestion to salvage the cables is about all you can do although a hammer and chisel/flat screwdriver could expose the board etc but the chances of anything surviving is very slim (possibly fun trying though).

You would be better off looking at Ebay, there are generally lots of power supplies there, sometimes it not much dearer to buy an Amiga that comes with a power supply and lots of extras as I have found out

Alternatively somewhere like Amigakit or another member may be able to sort you out with a replacement, there are no shortages of options for a power supply replacement

[pandy71]

key is remove epoxy brick from plastic case - use a knife or something similar to separate walls from epoxy. after removing brick You can use hot air gun , heated epoxy resin can be removed piece by piece - epoxy being soften and quite easily can be cut by knife or screwdriver in smart parts. temperature must be around or over 100 deg C then plastic case need to be separated or it will melt.

Epoxy can be dissolved by fuming nitric acid but this is expensive and all copper parts will be eaten by acid - it is safe only for Gold, Aluminum and similar to Platinum metals (etching by fuming nitric acid is common way to expose die of the integrated circuits for analysis)

[Zetr0]

@8bitbubsy

Acetone: Now - go eBay!

will point out that Acetone will also eat the surounding plasitics and the resin that the coil is based in - you can re-resin it - but the effort you you would be going to here is nothing short of insane!

As my good friend rkauer would say - sack the cables - bin the rest

I shall agree with that rkauer - he is one smart Amigo

[8bitbubsy]

ok...
I'll take the switch and mount it on the side of my 1084S (the original switch was broken and removed)... That will be nifty!

[pandy71]

Originally Posted by Zetr0

@8bitbubsy
Acetone: Now - go eBay!

Almost not work if this is epoxy resin... (but can work if hot - over 100 C deg under pressure but still slow)

http://yarchive.net/chem/epoxy_solvent.html

"
1. methyl ethyl ketone - readily available, but often ineffective

2. dimethylformamide (DMF) - great stuff, but hazardous!

3. cyclohexanone

4. cyclohexanol - will attack some phenolics, not an easy feat

5. methylene chloride - commonly sold as a paint stripper

6. carbon disulfide - extremely flammable

7. diethyltoluamide - great stuff, but hazardous!

8. trichloroethylene

9. ethylbenzene

10. dioxane

11. chlorobenzene

12. aniline - one of the few reagents that will attack polyimides and epoxies
"

and

"
Dimethylformamide is about the only solvent I know of that dissolves epoxy
at a speed likely to be effective in a normal lifetime. However, DMF is very
likely to damage the wood, and I would not use it on a potentially-valuable
item.

My experience has been that some chemical adhesives, such as epoxy on
heat-sensitive, porous material, are best attacked by mechanical means.
I'd recommend a gentle, patient, approach with a fine wire file to cut through
the epoxy, followed by other abrasives ( such as 600-1000 grit paper ) to
remove the residual epoxy. Depending on the adhesive and wood types, the
"

[Fingerlickin_B]

Filing inside a box enclosed on five sides sounds a bit tricky! LOL

I'm with the cut-&-run as above...grab the cables...this PSU can be consigned to the garbage bin.

Use the old cable & make a new PSU from a new PSU

PZ.