[TechAssist] Re: Panasonic TV CT-3269SCW Chas. AMEDP311 repeatedly blows regu...
- From: Gary McCartney <gary@xxxxxxxxxxx>
- To: techassist@xxxxxxxxxxxxx
- Date: Tue, 30 Dec 2003 17:37:12 -0500
Dominic, thanks for the information.
Yes, R808 and R809 are open. I will replace these later tonight when I
get back.
Question though. Is that 148V dc I have on the cathode of D825 going to
go down to 130V dc when I have the resistors replaced, or could there be
a regulator circuit problem which I need to look after first?
I think I will connect a light bulb in place of the HOT to start with
and see what happens.
Gary McCartney
McCartney Electronics
Guelph Ontario Canada
Est. 1984
email: gary (at) number63.ca
MDileo0000@xxxxxxx wrote:
>
> Gary,
>
> Info from a similar chassis ABP331.
> The 2SD2539 is a non damper transistor, the 2SD1880 has a built in damper.
> Your regulated B+ should be 130VDC. This B+ passes thru a fusistor pair R808
> and 809, 1 Ohm 1/2 watt. These pass B+ to/thru L803 and to pin 9 of the FBT
> out pin 10 to the horiz out transistor. Horizontal driver Q501 is fed by a
> resistor pair R510, 511 3.6k 3wt.
>
> Let me know if this helps with your chassis layout.
>
> Dominic DiLeo
> Atlantic TV
> Freeport, Maine
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> In a message dated 12/30/03 11:13:08 AM Eastern Standard Time,
> gary@xxxxxxxxxxx writes:
>
> > I have received the new regulator IC and HOT from Panasonic. I replaced
> > a number of capacitors, D825 and it's filter cap, and I checked the
> > flyback out of circuit with my HR Diemen flyback tester and it shows a
> > good collector waveform and 30kv readout. I installed the new reg. but
> > decided to use a 2SD1880 to test the set with until I know it is ok to
> > install the (expensive) OEM HOT 2SD2539. I fired it up on 95V ac on the
> > variac. The set does not start up. I get 148V dc on cathode of D825 and
> > I get 31V dc on the B+ pin on the flyback.
> >
> > I don't have a schematic to trace the reason for the B+ voltage drop
> > between the source and the flyback. I am only assuming that the cathode
> > of D825 is the (130V?) B+ source for the flyback. Tried tracing it on
> > the circuit board but got lost.
> >
> >
> > Any help appreciated, especially a partial schematic for this this
> > chassis or similar chassis which includes
> > an STR58041A regulator.
> >
> >
> >
> >
> > Gary McCartney
> >
> > McCartney Electronics
> > Guelph Ontario Canada
> > Est. 1984
> > email: gary (at) number63.ca
> >
> >
> >
> >
> >
> >
> > My original message:
> >
> >
> > I have worked on this Panasonic 32" TV model CT-3269SCW Chassis AMEDP311
> > about 4 times in the last year or so. One time the HOT and regulator
> > (STR58041A) were blown and I replaced with OEM Panasonic parts along
> > with a few supporting parts in the regulator circuit which I don't
> > remember at the moment. Another time the flyback was shorted. About a
> > month ago, the regulator was shorted so again I replaced with OEM part
> > and today the customer called and said he is bringing the set back in
> > first thing Monday morning, hoping to have it repaired for Christmas. He
> > heard a POP and the set went dead.
> >
> > It seems there must be something I am missing when I'm replacing HOT's
> > and regulators on this set. Is there a service bulletin or a known list
> > of components which need attention while serving? I have soldered the
> > hor. driver transformer. I don't work on many Panasonics but the ones I
> > do usually are dogs.
> >
> > I am wanting to be able to order parts by noon on Monday so I can
> > hopfully get this set shipped before I close down for the holidays.
> >
> > Merry Christmas to everyone and thanks for any help.
> > --
> >
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