From: "The Al Bundy"
Subject: Re: Help with a circuit
X-Newsreader: Microsoft Outlook Express 6.00.2800.1106
Date: Sat, 19 Oct 2002 00:49:16 +0200
NNTP-Posting-Date: Sat, 19 Oct 2002 00:38:00 MEST
Organization: @Home Network
"Craig Atkins" schreef in bericht
| Please help me!!
| This circuit: http://www.sire.co.uk/circuit.jpg
| is not working as it should.
| The input voltage at pin 9 is 90/100 VAC.
| The output voltages are all correct, apart from pin 4, which is giving
| out about 24VDC as opposed to 68VDC.
| The resistors R14 (10W) and R15(10W) both get very hot (understandable
| i guess, as they are 10W ceramics).
| The capacitors C10 and C11 used to also get very hot, but I have since
| changed these parts.
| I have also replaced TR1 and TR2.
| I am now stuck, due to my rather limited knowledge of electronics. I
| think that maybe TR3 isn't working right, but I'm probably way off
| Could anyone suggest which parts may be faulty and causing this
| voltage error?
| Thanks in advance!
At the cathode of D9 should be some 23Vdc.. If so (and not 68v), then check
Over the diode D6 you should measure some 3,9V. If there is 68V over the
diode D9 then TR3 is bad.
If the parts are correct then maybe even D5 can be broken/shorted.
Check also all the resistors. Never know if there is a bad one between. Just
can measure in-circuit. The resistor value that you measure should be same
or lower then the value of the resistor it self.