[TechAssist] Re: Mitsubishi VS-4543 PTV N/S correction FIX


<Groan>, yes the EEprom was corrupt.  I've just spent 6 hours going through
all the alignment menus.  I think it's good enough to ship now but I'm gonna
go over it once more in the morning when I'm fresh.  Geeze, people wonder
why these things cost so much to repair....
Thanks much.
Joel

----- Original Message -----
From: "Leonard G. Caillouet" <lcaillo@xxxxxxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Monday, March 31, 2003 10:52 AM
Subject: [TechAssist] Re: Mitsubishi VS-4543 PTV N/S correction


>
> Joel, check for leaky caps in general and also for coolant leaks.
> Specifically, this is from the mits site:
>
> CONVERGENCE AND RASTER DISTORTION
> Cause #1
> 1. GO TO THE CONVERGENCE MENU (MENU 2 3 5 9) AND CHECK THE ADJUSTMENT
> SETTINGS FOR CONVERGENCE. IF ALL ITEMS ARE SET AT "127". THE EEPROM
SETTINGS
> ARE AT DEFAULT. CLEAR THE CONVERGENCE MENU AND ACCESS THE OPTION MENU
(MENU
> 1 3 7 0) USE THE ADJUST BUTTON TO SELECT E2RESET AND PRESS QV. THIS SHOULD
> INSURE THE EEPROM IS CLEAR. AT THIS TIME ALL ADJUSTMENTS, CONVERGENCE
> GEOMETRY AND CONVERGENCE SHOULD BE DONE. 2. CHECK FOR 20 VPP VERTICAL
PULSE
> TO PIN 9 OF THE "GL" CONNECTOR TO THE CONVERGENCE PCB, IF MISSING, WEAK OR
> DISTORTED, CHECK PULSE AT SOURCE PIN 7 OF IC401 (PUMP UP OUTPUT) ON THE
> SIGNAL PCB, IF THE PULSE IS NOT CORRECT AT PIN 7 CHECK C402 100 UFD 50V
AND
> IC401 PART # 270P064020. 3. CHECK FOR -5 VDC TO THE CONVERGENCE PCB AT
"GM"
> CONNECTOR PIN 10, IF LOW, MISSING OR NOISY, CHECK C936 (1000 UFD 16 V) AND
> C935 (100 UFD 16 V) IN THE -8 VOLT SUPPLY CIRCUIT ON THE MAIN PCB. 4.
CHECK
> C924 (1000 UFD 36V 105 C) AND C925 (100 UFD 50 V) IN THE -24 VOLT SUPPLY
> CIRCUIT ON THE MAIN PCB.
>
> Leonard G. Caillouet
> Service Manager
> Electronics World
> Gainesville, FL
> 352-332-5608
> 352-332-5668 (fax)
>
> ----- Original Message -----
> From: "Joel Jacobs" <jj@xxxxxxxxxx>
> To: "TechAssist" <techassist@xxxxxxxxxxxxx>
> Sent: Saturday, March 29, 2003 12:34 PM
> Subject: [TechAssist] Mitsubishi VS-4543 PTV N/S correction
>
>
> >
> > Hello,
> > Received this PTV with no HV - was shutting down.  Found bad vertical IC
> > LA-7845 and two open pico fuses z900 and z903 - both 6.3a on +34 and -24
> > supplies.
> >    Now it comes up and has a picture but the raster is stretched
> vertically
> > and has severe bow at top and bottom.  E/W correction is weak also.
> >    I don't have a lot of info regarding the service mode on this set and
I
> > couldn't find a N/S or PIN adjustment.  I can get into the convergence
> menus
> > and the adjustments there seem to be working.  There are only red and
blue
> > adjustments though and the green is bowed too.
> >   On the print, I don't see any raster correction circuitry in the
> vertical
> > circuit which keeps leading me back to the convergence circuit being the
> > problem.  I believe side and top/bottom PIN correction is done through
the
> > convergence circuit - is this true?
> >   If I scope the signals on the convergence yokes I find there is no
> signal
> > on the green vertical winding.  Tracing it back I also don't have a
signal
> > at connector 'VY' from the digital convergence module so I don't think
the
> > problem is the STK392-020.  Then again, the red green and blue
convergence
> > is not bad, the entire raster is whacked out.
> >   Sorry for joining this list and diving right in with a help request
> before
> > I've had a chance to contribute.  I just been beating my head on this
one
> > for a week now.  Any help greatly appreciated!
> >
> > Joel Jacobs CET
> > Ohio Consumer Electronics
> > 31 Hill Rd. S.
> > Pickerington, Ohio 43147
> > 614-833-9696  M-F 10-6 EST
> >
> >
> >
>
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