Big blue thing looks like a Riva capacitor, also appears to be the capacitive dropper to feed electronics ; check it
Hi all,
I'm trying to fix a Speedrite 8000 electric fence unit. LED2 right side on DC side not flashing. Fuse OK,
The four diodes are not in a bridge rectifier config rather 2 in parallel then 2 in parallel with cathodes of 1st pair connected to anodes of 2nd pair.
Don't know what the 2 large red components top right are or the 2 blue at left of middle.
I assume silver mounted horizontal top middle is an electrolytic cap?
Most of stuff on AC side have porcalain beads protecting legs.
I'm trying to understand AC to DC path before I start removing live testing. Any help appreciated.
regards
Neil
Last edited by ngr; 27-01-20 at 02:30 PM.
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Big blue thing looks like a Riva capacitor, also appears to be the capacitive dropper to feed electronics ; check it
Ok. AC in via Large blue cap, on left, then through green wirewound resistor (Burnt check) through two more resistors to a zener diode. The large electro is then across this to create the DC rail.
First test. Is there any DC Voltage across that electro ?
The Varisistor (V1) after the wirewound resistor may be shorted.
remember to listen you can hear the oscillator if its working . the two resisters after the wire wound go high so you may not have sufficient rail volts . yes the v1 is most likely shorted as well
Thanks for your replies, finally had a chance to get back to it.
DC across large metallic cap and large diode, need to test SCR2 (if it is).
Couldn't find anything exactly on it, Is it a SCR? Was covered in shellac, possible replacement part if faulty?
What is is purpose here?.
thanks in advance.
neil
Looks like the SCR with heat sink is crook.
That's a bt151-800r thyristor (SCR) ...cheap as chips ...
The condition of the output transformer (and other components) should be checked before replacing with new one and blithe-fully turning the power on
Thanks, the TYM825 with the heat sink is shorted between A & C and $2 at RS, but I have to buy a tube of 50, I'll have 49 spares
I thought smallest SSM was 5 units... oh well, depends where you are I guess =)
The scr wont be the final fault
wotnot (02-02-20)
hinekadon (03-02-20)
Finally got back to it.
Hinekadon was right, the 4 large diodes were crook as well (shorted). Replaced them and all good.
Thanks everyone.
Interestingly i thought things would go open, not here the higher currents may have something to do with it?
hinekadon (15-02-20)
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