Dodgy JVC RGB SCART socket input

[Jenny Talia]

Hi all, any useful advice would be mucho appreciated

I have a 1998 JVC AV-29S2EK (UK PAL) TV and recently tried to use the RGB
input facility of SCART socket 1 and the Blue signal is not getting through,
(yellow cast to picture and whites are yellow).
(Have never used the RGB input in the past).

Normal TV input, composite input through the same SCART and S-video through
another SCART give a picture of normal colour.

Both Scart cables tried and RGB source (UK digital TV decoder) proved OK on
another TV.

When I measure resistance across the RBG input + ground pairs the Red and
Green circuits quickly ramp up to about 70 Ohms, (assuming a capacitor in
circuit charging up), the Blue sits at around 0.5 ohms.

I "imagine" that the R,G,B, input circuits must be fairly minimal, virtually
straight to the guns?.

Could it be just a duff cap in the blue input line from SCART 1 ?.

Thanks in advance for any insightful input and advice.

P.S. Dab hand with a soldering iron etc, have repaired some VCR PSU's and
some CCTV processing equipment(transmission, multiplexers, switchers, PSU's)
and yes I do know how the dangers of TV HV circuits before a kind soul
advises "the little lady" about that.

Regards
Jenny

 

[Jerry G.]

It sounds more like you have a short on the input , rather than an open.
Defective capacitors generally go opened, not shorted. But, once in a while
I have seen a shorted cap. The other side of the cap, may be going to a
high impedance input, so if the cap was shorted and the short was not before
the cap, the meter would read a high resistance. I am sort of guessing here,
because I do not know the particular design of your set.

I would first look to see if there is a short right on the input of the set.
The 70 ohms you are reading on the good channels is the termination resistor
for the video. It should actually be 75 ohms ideally.

This is all speculation to where I would start...

--

Greetings,

Jerry Greenberg GLG Technologies GLG
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"Jenny Talia" <asif@getreal.com> wrote in message
news:bs2g8b$297$1@newsg2.svr.pol.co.uk...
Hi all, any useful advice would be mucho appreciated

I have a 1998 JVC AV-29S2EK (UK PAL) TV and recently tried to use the RGB
input facility of SCART socket 1 and the Blue signal is not getting through,
(yellow cast to picture and whites are yellow).
(Have never used the RGB input in the past).

Normal TV input, composite input through the same SCART and S-video through
another SCART give a picture of normal colour.

Both Scart cables tried and RGB source (UK digital TV decoder) proved OK on
another TV.

When I measure resistance across the RBG input + ground pairs the Red and
Green circuits quickly ramp up to about 70 Ohms, (assuming a capacitor in
circuit charging up), the Blue sits at around 0.5 ohms.

I "imagine" that the R,G,B, input circuits must be fairly minimal, virtually
straight to the guns?.

Could it be just a duff cap in the blue input line from SCART 1 ?.

Thanks in advance for any insightful input and advice.

P.S. Dab hand with a soldering iron etc, have repaired some VCR PSU's and
some CCTV processing equipment(transmission, multiplexers, switchers, PSU's)
and yes I do know how the dangers of TV HV circuits before a kind soul
advises "the little lady" about that.

Regards
Jenny