"Franc Zabkar" wrote in message
...
On Tue, 16 Aug 2005 11:13:11 +0100, "N Cook" put
finger to keyboard and composed:

Jou Jye 300AP
Blown 5 amp mains fuse
There is a 1/2W resistor between the common point of the 2 x 200V mains
side
electrolytics
and one of the 2 leads , high V side of the large isolation transformer,
marked on pcb as R5 now reading 98 ohms
Overheated and probably had a brown and a red band somewhere in the
value.
Covered with some 125 degree shrink-sleeve that has charred. This was to
protect against touching other parts but this R was on end and lead
doubled
back and presumably the bang was the long lead shorted to the other
barrel
end of the R as severe tell-tale smoke 'jet-trails' at that point, no
ceramic spacer or anything .

Anyone hazard a guess what the original value might be. ?
The 2 main 2SC2625 and 200V electrolytics seem OK.

Parallel to the 4 wires of the mains side bridge rectifier is a small
sub-circuit
with (2S?) K2645 and a L8561 8 pin IC, is this all a crow-bar circuit to
knock out the mains fuse?

This smaller circuit is probably the +5VSB standby supply.


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

It is a power factor corrector sub-circuit, would seem.
Does that mean all those millions of PC SMPS without this corrector are
getting free electicity off the generating company?
Until I got oblique lighting just right very difficult to read IC number
and it is L6561
http://www.st.com/stonline/products/...5109/l6561.htm
It looks as though the burnt resistor (2W not 1/2W as previously said) was
1K from the bands so dropping from 1K to about 100 may be the initial
problem.

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