Mitsubishi Proj. model VS6043A (4 of them same strange problem)
 

I made a service call today to a bar where they have 15 of these sets
throughout the building. There are 6 in a row on this one wall. The
sets are fed from a 16 tap splitter fed from a distribution amplifier.
The 16th position is terminated. I'll try to describe this symptom as
best as I can. Three of the sets on this wall seem to have what I at
first thought was symptoms that mimicked a signal ingress into a cable
like from a loose fitting. The picture has small straight across
horizontal lines that wave through it at varying rates. I checked all
the fittings in the distribution and although many were loose
tightening them did not improve the situation. I got to the back of one
of the affected sets to check the fitting and it was tight. I
substituted a new wire to this one set but it did not make any
difference. I swapped cables in the splitter too. I also tried the
alternate RF input but with the same result. I was starting to suspect
tuner problems until my son switched one of the sets to line and we
noted that the wavy lines were also present on the blue screen with no
video input. So it does not seem to be an RF problem but it is
affecting three of the sets on this one wall and one other in a
different location in the building. Is anyone familiar witrh anything
common on this set that sounds like the problem I'm having? It just
seems odd that four sets are similarly affected. Thanks very much for
any assistance. Lenny Stein, Barlen Electronics.

IIRC there are some 100 uF caps near a couple of 78XX series
regulators. They're on the signal board and I think you can just about
see them as soon as you take the back off.

They may check good or marginal on some ESR meters.

JURB

Jurb
I don't mean to sound stupid but what is "IIRC"? Are these caps in the
LV power supply section because this does sort of look like a power
supply ripple effect of some sort? Is this a common problem on these?
The thing is if I can't fix these sets on site I won't have anyone to
help me haul them back to the shop. And I'll probably be burned for the
time i will invest in trying. Thanks very much. Lenny.

wrote:
Jurb
I don't mean to sound stupid but what is "IIRC"? Are these caps in the
LV power supply section because this does sort of look like a power
supply ripple effect of some sort? Is this a common problem on these?
The thing is if I can't fix these sets on site I won't have anyone to
help me haul them back to the shop. And I'll probably be burned for the
time i will invest in trying. Thanks very much. Lenny.

Hi...

If I recall correctly, IIRC means If I Recall Correctly :)

Sorry, couldn't resist :)

Ken

Thanks I'll have to remember that one. My wife says I'm way too
verbose. Thats when shes being nice. Lenny,

Those capacitors fix 90% of the problems with those.
It is strongly suggested you take along a good flashlight and esr meter
to do a good check across all the boards paying special attention to
the power supplies, scan circuits (H&V), and the video circuits for any
signs of leaking capacitors or high esr ones.

It has been my experience on that series rptv with the regulators that
I usually would find about 2 to 3 dozen capacitors clearly bad. I
would take about 10 minutes visually going over each board and checking
esr and would mark the top of any suspect capacitors with a permanent
marker. Then I could make a list of the values needed and replace all
of them at once. Total repair time per set of actually working on it,
less than 2 hours. Number of call backs, ONE: the first one that I did
not go over every board the first time.

Ken Weitzel wrote:

Hi...

If I recall correctly, IIRC means If I Recall Correctly :)

Sorry, couldn't resist :)

Ken


I think Ken is right, IMO..

John