I have the same problem - the old, original "D"-shaped Pace box. Started playing up a few weeks ago.
I took the top cover off and found one of the 220uF capacitors getting hot. Not sure if this may be the problem - I've not been able to find a suitable replacement capacitor. Also, the small square SM chip close to it on my box is also quite hot - adding freezer to it all made no change; it still holds at the green led. Eventually (after some minutes or more), it does go back to normal operation - till it gets powered off.
Agreed, we are in a throw-away world these days, but if it can be repaired, I, for one, would like to make an attempt and am prepared to "have a go", even if it's a totally unsuitable replacement capacitor to try it out.
It may not even work; who cares? At least I'll have had a go at it fixing it.
If anyone knows of a fix for this - do please add your comments.
Dave188, October 2008