Stuck on "ON"

[ellen1]

do i need tochange d7
and d8

[jambutty]

Elen,
with all respect it's no use posting a thred stating do I need to change d7 or d8.

On a kv psu there are 14-15 caps and 11 diodes, and without testenig them then yer can't assume it's a certain component thats causing the fault just because some people have had a problem with diode 11 or cap 11, 12, 20, 21, becuase it's not just these that cause a psu to stop working.

Yea on average yer can check the known caps/diodes that are suspect but these aren't alaways the culprits, it could even be a shorted diode plus 1 or 2 caps that need replacing, by all means replace the components yer think are blown but it's not always that simple.

as I said on a previous post a few days back, I have repaired loads of K, Eurovox psu's and all have diffo faults on them, the one I did a few days back had a knackered diode at D7, it was deffo shorted so I whacked a diode in BUT this didn't resolve it cos when I fired the box up the LCDwas flashing 88 constantly, so rechecked psu and found out that a capacitor had aslo shorted so replaced this too and then box was ok.

so it's not just down to 1 bad component, it could be or couldn't be, so without testing with a AMM/DMM or esr tester then yer got no way of acuartly knowing the fault, but on the stuck on on issue I can only say that chances are it's diode 7 on the psu BUT not gaurenteed to be just this, only way to find out is stick yer MM on the diode 7 and if reading both ways, then it's deffo shorted and needs replacing, may just be the diode but has stated could also be a bad cap elswhere.

Jam