[TechAssist] Re: Sony kv32s45 blows R607 no power
- From: "Damon" <DAMON101@xxxxxxxxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Sat, 5 Jan 2002 08:24:51 -0500
Ok, do you have a Variac?? You'll need it for this. Replace blown parts and
install variac - set it to 30 volts ac and turn it on. I suspect that using
a scope on the Q601 E-C connection point that you will find the duty cycle
(turn-on vs turn-off) to NOT be 50%.
Check the resistors connected to the Base pins, diodes @caps too. (Don't
have my schematics in front of me). These set the timing of the Ic's duty
cycle. Of course you may also have NO oscillation at all and one side of
q601 is being turned on all the time, if so then the tuning caps for the
Pit, Prt, or Smps xfmr come into question, (Remember, no schems in front of
me).
But that situation will kill q 601 immediately. Hope this helps.
Damon Brunger
damon101@xxxxxxxxxxxxxx
Telrad Electronic Services
Ft Wayne, IN 46815
----- Original Message -----
From: "Rochester Electronics" <pasthecash@xxxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Friday, January 04, 2002 11:56 AM
Subject: [TechAssist] Sony kv32s45 blows R607 no power
>
> Hi guys,
> hope someone can help with this one.
> Sony KV-32S45, came in for no power up. found open R607 on
> power supply (G Board) and didn't find anything els
> suspect.
> but changed the the regulator IC601 and the r607, removed
> vdr602 and checked out of circuit it seems to be ok.
> Checked the HOT in and out of circuit. checked d603 and
> d604. all seems ok.
> plug set in and imediatly blows R607. Thought i might have
> a bad regulator so i changed it again just because i had
> one. same problem. With the power supply unplugged fron
> the rest of the set seems ok however i have no print. From
> cn641 all i get is the standby 5v but i bet that it needs a
> sygnal from the main board to set one of the relays. Not
> sure where to go from here. Heeeelllllpppp...
>
> TIA
>
> Mike
>
> =====
> Mike
> Rochester Electronics
> 716-663-6870
> www.RochesterElectronicsRepair.com
>
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