[TechAssist] Re: fix Re: GE 25GT522, CTC177AF2 powers up 3 times,dead.

  • From: Phil Bader <tjanphyl@xxxxxxxxxxxxxxx>
  • To: techassist@xxxxxxxxxxxxx
  • Date: Wed, 25 Feb 2004 09:18:37 -0500

I now understand in retrospect.
Remember I said with the new eeprom, the set came on, but the horizontal freq 
was off? (due to the incorrect value of the new eeprom's horiz freq setting)
Another words, "detuned". A detuned resonant circuit is less effecient, so with 
the horiz freq off, that affected the high voltage, lowering it, allowing it to 
stay on. As I brought it closer to correct frequency, the HV increased, until 
it exceeded the normal amount and triggered shutdown.
The open scan cap was allowing excess HV. My replacement eeprom with it's H. 
freq "off" just masked the actual problem.
Does this explain it better?
It threw me also for awhile.
Phil

Paul wrote:

> Phil, If the set stayed on after replacing the eeprom, why did C4402 need 
> replacing? Did I miss something somewhere? If C4402 was the cause of the 
> problem would it not still cause the same problem with a different eeprom? 
> Are you saying the eeprom made up for an open timing cap?            Paul
> Phil Bader <tjanphyl@xxxxxxxxxxxxxxx> wrote:I threw an eeprom in(slightly 
> different ctc177 model) and the set stayed on...out
> of horiz. hold. I managed to enter the service menu and get to parameter one, 
> H,
> freq. Just as I had it close the H. oscillator dropped out.
> I attached an external scan cap (just something out of my cap box, like a
> .001@2kv) and it fired up with good picture.
> This told me a timing scan cap somewhere was bad.
> I located C4402 ,a .0115mfd@1600V (RCA# 223177). It was open.
> Replaced C4402 as the fix
> .
> Philip Bader
> Jan Phyl TV Inc. (estab. 1976)
> 3420 Recker Hwy. Winter Haven, Fl. 33880
> Fax (863) 299-8821
> email: tjanphyl@xxxxxxxxxxxxxxx
> Phil
>
> peggs wrote:
>
> > throw an 8 pin socket in, and try a new EEProm
> >
> > Peggs
> >
> > At 10:37 AM 2/24/04, Phil Bader wrote:
> > >Plug it in, the SMPS has the usual chirp, and the HOT collector is at
> > >about +148 VDC in standby. Push power while monitoring the HV anode and
> > >it turns on, HV comes up to about 25KV, instantly clicks off, clicks on
> > >again in half second, off, then a third try, then dead. I didn't see a
> > >bad fly with HV coming up OK.
> > > I checked all diodes, found no shorts.
> > >Histories?
> > >
> > >Phil
> > >
> > >--
> > >
> > >Philip Bader
> > >Jan Phyl TV Inc. (estab. 1976)
> > >3420 Recker Hwy. Winter Haven, Fl. 33880
> > >Fax (863) 299-8821
> > >email: tjanphyl@xxxxxxxxxxxxxxx
> > >
> > >
> > >
> > >
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> Paul ,B                                                                       
>                                        Central TV&Video                       
>                                                                               
>      Grover Beach Ca.
>
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--

Philip Bader
Jan Phyl TV Inc. (estab. 1976)
3420 Recker Hwy. Winter Haven, Fl. 33880
Fax (863) 299-8821
email: tjanphyl@xxxxxxxxxxxxxxx




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