Surprise in wall wart.

[boxdoctor]

I have a Lowe HF225 receiver bought c.a. 1990 which started acting erratically last year.
Eventually the fault was traced to an unstable powerv supply.
Upon opening up the faulty (manufacturer supplied) wall-wart, I discovered that the regulator I.C. was hangng loose in it's mounting holes in the badly charred P.C.B..
Aggravating this problem was a small tag made from about 2c.m. of thin tin-plate pop rivetted to the reg. as a token "heatsink".
A new supply was properly built in a small ventilated metal box. - Problem solved.
Ok, so maybe Lowe bought these in (?cheaply) from a far eastern manufacturer, but I think they should have taken one to pieces to see what was inside. The rest of the set was of a high enough standard to warrant at least that much inspection ! Tony.

[ortek_service]

Although 30year life from it wasn't too bad, they could argue!

However, relying on solder joints alone for mechanical support of heavier components isn't recommended.
And it's possible that thermal cycling from use had weakened the joints, causing them to crack and then arcing - a common occurrence on cheaper PCB's that didn't have through plated holes which tended to also stop joints cracking.

Something they used to affect many older CRT TV's, with manufacturers sometimes putting in extra metal eyelets / standoff metal tubes, to reinforce the connections.

[emeritus]

I remember getting a switch-mode power supply from Maplin and finding that the internal instruction leaflet said it was for computer equipment use and was not suitable for use with radios, so it went back. There was no such warning on the outside of the box or the catalogue entry.