Re: ASTEC 150W AC/DC SMPS power supply

Is this Z4 shaped like a disc & connected in primary winding area just
like the transistors ? If this is true then looks like Z4 is a
varistor. Check the power supply without Z4 to see if this is the cause
of short circuit.

sidneybek@xxxxxxxxx wrote:
I am working on a ASTEC 150 watt AC/DC SMPS power supply
model:LPQ154,CSA File No:LR84459,year:May 1995:

http://www.astec.com/products/datasheets/lp/lpq150.pdf

I found the outside 3 amp long fuse burnt,F1=5 amp small (on the main
board) burnt,along with Q1=IRF840 and Q2=IRF840 in the troubleshooting
process I assumed Z4= was shorted but it wasn't and I broke it in two.
Does anyone have the value for Z4=Zener diode?,the # I got off it was
something like "2C2" which if correct is 2.2v but when I put one in
along with new Q1 &Q2 the unit's secondary voltages try to climb but
the 100 watt light bulb I placed in series with the line voltage is
limiting the current and thus preventing the same failure of parts.

Sidney
E-mail:sidneybek(at)yahoo.com
Dartmouth,Nova scotia
Canada

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