Goldstar CNR-2994P Tuner problem
 

The set may need a new tuner module.

--

Jerry G.
=====


"Boris" wrote in message
om...
Hello!
I really liked the quality of the some of the posts in this group.

So here is the problem: I got (from a sale) a very nice GoldStar
CNR-2994P TV. After fixing the power supply problem, which I guess
caused the owners to sell it, I am left with a strange tuner problem:
poor reception quality for most (may be all) channels.

Summary of diagnostics:
* Although I am able to receive a few (2) channels very well, the main
aired channels in my area are shown with poor quality (unlike on my
other TV). The TV is generally of very high quality and I would expect
at least to match the other TVs in terms of receiver sensitivity.
* DVD and VCR play though the RCA jack is excellent (which brings the
problem down to the tuner)
* Sound is excellent on all channels
* There are two standalone (and looking identical) tuners to support
picture-in-picture. Unfortunately, all menus are in Korean language
and I still haven't been able to find a translation. So, I am not
exactly sure how to test both tuners one by one (or even how to invoke
the small picture).
* There are 3 power supply voltages on each tuner pins: 5, 12 and 33
volts. They are all a little bit lower, but the biggest difference
(from the nominal) is in the 33V, which is 29.5V. This is quite
strange since this 33V is produced from 40V coming out of the power
supply, which is in reality 50V (the only power supply voltage out of
normal range). The raw voltage is higher while the zener voltage 33V
is lower (could be a filtering problem)! Both tuners have the same
29.5V instead of 33V.
* Due to difficulties with Korean, I haven't been able to fully
understand the menus, but the AutoProgram also seems to have a
problem: some strong channels are visible but not recorded
automatically.

Any help with debugging the problem would be appreciated!

Tuner problem
 

Can anyone here advise me how to determine if the tuner is broken (versus
tuner supply voltages or subsequent circuits)? Unfortunately, no schematic!
Thanks,
Boris

"Jerry G." wrote in message
...
The set may need a new tuner module.
Jerry G.

Tuner problem
 

Not without some more information; make, model, chassis, symptoms...

Tuner problem
 

Well, I thought I have described the problem details well in the first
message of this topic. Basically, relatively poor (still watchable)
reception quality (definitely from the RF tuner portion).
Model: GoldStar CNR-2994P

"BWL" wrote in message
...
Not without some more information; make, model, chassis, symptoms...

Tuner problem
 

If you're still getting a watchable pic, then the tuner is at least
functioning; may have low or missing AGC voltage (typically about 8volts at
full gain); also may have loose or broken isolation capacitor inside antenna
connector(if the TV uses one). Possible weak RF amp inside tuner, but subbing
with new tuner is really the only way to test for this