[TechAssist] Re: Symphonic SC313C Combo Service Manual need explanation ?

  • From: "Intrepid Video Support" <support@xxxxxxxxxxxxxxxxxx>
  • To: <techassist@xxxxxxxxxxxxx>
  • Date: Thu, 23 Sep 2004 23:12:04 -0400

Randy,
I wish mine was the easy...33v zener still blowing and no cracks..
For yours, suspected a damaged micro.
Jeff
--
Intrepid Video TV/VCR Repair
263 S Front St, Steelton PA 17113
717-939-7708; (F) 717-564-4952
www.intrepid-video.com  www.tech-repair.net
----- Original Message ----- 
From: "Randy Evans" <tvsvc2000@xxxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Tuesday, September 21, 2004 11:52 PM
Subject: [TechAssist] Re: Symphonic SC313C Combo Service Manual need 
explanation ?


Hi Jerry:

This one uses a PC817 Cpto-Coupler.
The PCB was cracked in this area, where the screw fastens the PCB to the 
plastic frame.  I did find
cracked solder on Q604 Emitter too, which is in the same vicinity
as the Opto-Coupler.

Thanks for the help, as always !

Randy J. Evans
VCR SERVICE
Delta, Ohio 43515
J Silverman <greentron@xxxxxxx> wrote:
If that set has a 431 reference IC for feedback in the secondary, check it
carefully for cracked solder. As I recall, the IC was over the support frame
and the bumping would crack the solder. Saw the same problem in three
similar models.
Jerry Silverman
Greentron Inc
4 Newland Ave
Greenville SC 29609
Fax/Phone 864 232 3889
mail to: greentron@xxxxxxx
----- Original Message -----
From: "Randy Evans"
To:
Sent: Wednesday, September 08, 2004 10:09 PM
Subject: [TechAssist] Re: Symphonic SC313C Combo Service Manual need
explanation ?


> Hi John:
>
> Thanks for the response !
>
> I don't have a problem with the T601 Transformer on this SC313C,
> but I do have D615 (33v Zener) shorting out at random time intervals, and
I can't
> locate any bad parts that might be causing it to short, although I suspect
a
> crack in the PCB somewhere.
>
> If you look at a manual for other Funai/Symphonic models such as the
SC3809, the power supply
> test procedure instructs you to attach the scope probe to a pin that
doesn't
> exist on the transformer..... (such as pin 16, and the transformer only
has say 14 pins)
> so I guess the author made mistakes.
>
> Thanks for the help. I appreciate it very much !
>
> Randy J. Evans
> VCR SERVICE
> Delta, Ohio 43515
>
> John at Main TV wrote:
> SC313C manual should be the correct manual. The transformer should have
> pins numbered 1 thru 16 (there is no pin 3), the secondary pins are 11
thru
> 16 with negative of scope (ground) to 12 and positive to 16. That is a
> strange connection since 12 is not ground but then the waveform is strange
> also. Are you saying your set does not have 15 pins on the transformer?
> What is the problem with the set, does it work but makes a squeal from the
> power supply? John.
> John Mielke
> Main TV
> 636 main St.
> Longmont, Co
> phone 303 776 6955
> fax 303 776 0792
> maintv2004@xxxxxxxxxxx
> ----- Original Message -----
> From: "Randy Evans"
> To:
> Sent: Wednesday, September 08, 2004 10:45 AM
> Subject: [TechAssist] Symphonic SC313 Combo Service Manual need
explanation
> ?
>
> > In the Power Supply Troubleshooting sections of their Service Manuals,
> they tell you to connect your Scope Probes to two terminals of T601, the
> Switching Transformer. In almost every Service Manual, they tell you to
> connect it to "Pins that don't even exist" on the transformer.
> > What I need to know is: What Winding are the talking about?
> > Positive Probe to ?? Negative Probe to ??
> >
> > I Copied and Pasted an example from a Symphonic SC313 manual below,
> > although it is in their other combo Service Manuals as well.
> >
> > Thanks,
> > Randy J. Evans
> > VCR SERVICE
> > Delta, Ohio 43515
> > tvsvc2000@xxxxxxxxx
> >
> >
> > 13" COLOR TV/VCR COMBINATION
> >
> > SC313C 6313CC EWC1302
> >
> > Page 1-8-15
> >
> > Power Supply Trouble Shooting Guide
> > ---------------------------------------
> > The transformer of the power
> > supply makes a higher sound
> > or the oscillation wave form is
> > abnormal.
> > (E.g. intermittent oscillation)
> > Connect the positive probe of
> > oscilloscope to the pin 16 of
> > T601, then connect the negative
> > probe to the pin 12. Observe the
> > waveform and check to see if
> > the waveform is out of limit of
> > value shown in Fig.1.
> > ---------------------------
> >
> > Voltage approx. 5Vp-p
> >
> >
> >
> > ---------------------------------
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> > New and Improved Yahoo! Mail - Send 10MB messages!
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