[TechAssist] Re: ATC311 Sweep board component level repair.
- From: "Wayne Vanaman" <Wayne@xxxxxxxxxxxxxxxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Wed, 5 Nov 2003 13:46:48 -0600
Actually the convergence is stored in a couple of eeproms. On these sets
there is a default convergence in one eeprom which can be loaded into
another "working" eeprom. With a convergence problem you would normally be
able to align the convergence and get a good picture. At that point you
would have the wise option to store that data to the default eeprom. If you
do not store the data to the default eeprom the set will work until the
customer does the autoconvergence, even if power has been out awhile.
For the set to have a "non-correctable" convergence problem would entail
more than one eeprom. I currently have a convergence pcb on order for a
customer. On his set the 480i and 480p convergence data could be stored,
but the 1080i data could not be stored.
I have only repaired a half a dozen of these, and this is the only one I
have had a convergence problem with. Initially after replacing a badly
burned circuit board the set would not converge. Replacing the eight
convergence sensors solved part of that.
This may also turn out to be an interesting finish as the owner of this set
is one of three co-owners of a company that supplies parts to RCA, and I
have fixed one of the owners sets, and looking forward to meeting the
third...while this repair is dragging along...
As a side note, this high voltage splitter is mounted in the same trashy way
as the ptk195s, and I have seen arcing between the chassis ground and the
splitters ground plate when the mounting screw is not tight. I always add a
jumper wire from the splitter ground lug to the chassis. I noticed that the
ATC221 chassis also have a ground jumper installed.
Wayne Vanaman
Omega Electronics
6904 W Fairfield Dr
Pensacola, Fl. 32506-3310
Wayne@xxxxxxxxxxxxxxxxxxxxx
WWW.PensacolaTVRepair.Com
850-456-5995 voice
850-458-6369 fax
----- Original Message -----
From: "peggs" <peggs@xxxxxxxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>; "Tech Assist" <techassist@xxxxxxxxxxxxx>
Sent: Wednesday, November 05, 2003 2:23 PM
Subject: [TechAssist] Re: ATC311 Sweep board component level repair.
> Isn't the convergence 'stored' in an EEprom ???
> Maybe it got zapped on the original/component repair module
>
> Peggs
>
> At 09:51 AM 11/5/03, walter wood wrote:
> >Jason at Excel was kind enough to provide some
> >extra input on the HV splitter issue in the ATC311
> >thomson chassis.
> >Reference Thomson bulletin TV-03005.
> >I've had 8 of these things and on 5 of them
> >replacing the splitter and R14705 238958 27k common
> >1/2 watt resistor repaired the sets.
> >When the power/sweep board is replaced(according to
> >Thomson tech support), the geometry and convergence
> >must be set.
> >That's a bear, as I still don't have the adaptor
> >for Chipper Check to do this.
> >So, I tried the component level fix.
> >The extra parts are:
> >R14718 260880 120K 1/4 watt
> >R14718 175046 30K 1/4 watt
> >CR14703 198589 diode
> >Q14401 243834 2sc5522 transistor.
> >On this particular set R14718 and Q14401 were the
> >only other failed components. I did replace all six
> >however.
> >
> >This repaired the set, BUT, the convergence is off
> >exactly as the complete module I replaced.
> >I've done both,module and component repair on this
> >set in order to answer some questions, but I only
> >got more questions.
> >Apparently, it's not the changing of the
> >power/sweep/back end processor, that causes the
> >convergence problem.
> >So, the splitter's arcing must damage another
> >board.
> >Any ideas??
> >TIA
> >Walter
> >
> >=====
> >Walter Wood
> >Future Tech Home Center
> >2786 Hwy. 43 N.
> >Lawrenceburg Tn. 38464
> >931-829-3337
> >Fax 931-829-4044
> >mailto:wwood_38478@xxxxxxxxx
> >
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