oops! coffee into the top of TV!
Robert Macy
EVENTS: Set coffee cup on top of TV, jostled the TV's table, liquid
went down through the holes on top, and voila! Screen shrunk, went
black - However, I quickly unplugged just as TV was going black.
DIAGNOSIS: Took apart case to find liquid had run onto the HV
connection, ran down HV cable to where cable was lying against the PCB
on back end of tube. At that location, suspect arc over to
electronics [Electronics was a bare solder tab sticking out with bare
copper wire going to a winding] and what appears as a 1/16 inch
discoloration on side of HV cable. Possibly always touching there and
that was dirt aging, or from an arc caused by the liquid.
ACTIONS: Cleaned everything up, dried off, reassembled. TV came on!
Lit up! Talk about lucky. But...colors went all wonky. At first
everything was all red [must not have been completely dry]. Let run a
couple of hours to dry completely, Colors shifted, but now
predominantly green.
OBSERVATIONS: White appears to contain excessive green. Good news is
that pure red is pure red. pure blue is pure blue. Black and White
programs are green and black, not black and white.
For what it's worth, I think I've seen this type of color once on a
similar inexpensive TV caused by some cheap pots near the CRT. Those
little plastic disk thingies with a metal wiper. All the structure's
are open to the atmosphere and not sealed at all. Simply, ajusting the
color [wiggling the wipers] returned color to original settings,
brought the color back that time.
QUESTIONS:
1) Any schematic for a Funai FT1371 ?
2) Anybody know what got zapped on the top tab of that PCB?
3) Assuming each video color channel is still capable, what adjustment
to bring back color balance?
William R. Walsh
Just out of curiosity, how'd you dry the TV?
Water can hide in controls and components. If you didn't, I'd put the
opened TV in the sunlight for a while. The natural heat will drive
moisture out of the places where you can't see or directly dry it off.
William
b
>
> QUESTIONS:
> 1) Any schematic for a Funai FT1371 ?
> 2) Anybody know what got zapped on the top tab of that PCB?
> 3) Assuming each video color channel is still capable, what adjustment
> to bring back color balance?
I would not advise you to make any colour balance adjustments. These
are not usually used unless to compensate for component drift with
age, or after replacement or other scenarios where recalibration is
needed; the problem here probably lies elsewhere.
Only tweak if you are sure liquid got at the pots, and even then, mark
the original position with correction fluid or a marker pen. The fact
that you have already seen the colour shift from red to green might
well mean that all is not yet dry.
Firstly try removing and reinserting the small pcb on the neck of the
tube, check to see if any liquid made it to the pins or the CRT
socket. Usually this pcb contains the RGB output IC or
transistors...how old is this TV?
-B
Robert Macy
Thank you for your reply.
Should be dry. It's been 48 hours with perhaps over 30 hours of
operation. This TV being old runs a bit toasty. At the timeof the
accident, I expected the residual heat, coupled with the constant
operation since then, to be able to thoroughly dry everything out.
Also, being in California, drying is fast.
Will try that remove insert. and generally mechanically manipulate
everything. I don't think the PCB itself was washed, rather the HV
electrode wire was washed, flooding down to the bare terminal on the
PCB where very likely grounded out the HV. That's why the image
shrunk ultimately going black as the HV died. There is high
probability that the short to gnd path 'injured' low voltage
components.
White is not white, but greenish, like underwater now. I can't tell if
a color is missing, or green is simply too strong. It appears that red
is there, blue is there, green is there, flesh tones are almost ok,
but not quite. It may be that 1/2 blue is now 1/8 blue, or such. Like
very distorted transfer function. like a leaky transistor that keeps
signal very low until finally it can get turned off. And leaky
transistor would make sense with a zap going into the PCB somewhere.
It would help to have a schematic yo find out just where that
discharge entry point was.
Age? label said manufactured January 1998
Funai Model FT1371
Robert