[TechAssist] Re: [Fwd: Mitsubishi VS4003R projo.vert.flip left side after warm.]
- From: "Jerry" <geiting@xxxxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Sat, 15 Jun 2002 17:17:20 -0400
Phil,
These sets have a lot of problems with leaky electrolytic caps. As well
as checking caps in the vertical and convergence circuits, be SURE to check
the ones in the power supply. If memory serves, this set uses two switching
regulators and there are a couple of caps in primary circuits that will
cause the regulated output to go too high.
Jerry Eiting geiting@xxxxxxxxxx
Christians Electronic Service
Piqua, Ohio
----- Original Message -----
From: "Phil Bader" <philbad@xxxxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Saturday, June 15, 2002 9:10 AM
Subject: [TechAssist] [Fwd: Mitsubishi VS4003R projo.vert.flip left side
after warm.]
|
|
| Hard to explain this VS4003R PTV (1991 yr). First came in for "lines
| thru picture" which was bad
| solder around the LA7838 vert IC.We also replaced the IC as precaution
| and an electrolytic positioned inside the LA's heat sink(100 mfd@25V).
| Cured that. During the several days test playing we saw another symptom:
| after about 2-3 hours the vertical seemed to quickly "flip up/down but
| worse on the left.The whole display did move.All 3 tubes affected.We
| thought it looked like a convergence problem so moved the conv. panel
| outside the set (has a foot long cable bundle) and closed the case. The
| set ran days OK. If I keep that convergence board cool,all is OK. I have
| changed all four of the STK's on it( STK4024-2,two STK4274's,STK4275),
| and resoldered extensivly.Same blasted thing.I tried hot air blower to
| no avail. I am
| wondering if a borderline ESR problem exists with some of the caps,that
| don't show while on the bench.We have theorised whether it was vertical
| deflection on defl. panel or is it convergence. Warmth of the conv.
| panel definately
| triggers it.Open the front bottom panel to access it and in five seconds
| it clears! Sorry for long post,I am desparate!-Phil Bader
| --
| Philip Bader
| Jan Phyl TV Inc. (estab. 1976)
| 3420 Recker Hwy. Winter Haven, Fl. 33880
| Voice/Fax (863) 299-8821
|
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