I have a magnovox model #RJ5540-AK01 that only picks up snow and no
sound on all channels. The cable connection is good (from a sattelite).
Set initially had only black raster, but now has decent brightness
since tapping on CRT neck board. The rear A/V jacks give a perfect
picture and sound. I suspect a bad tuner, but how can I determine if
the tuner is bad, and is there another suspect compenent I can check. I
am a beginner and have only been working televisions for about 1 year.
Thanks group for any suggestions.

well, tapping on the neck board to get the picture back indicates to me
you've got a tube going bad, or bad solder joints on the neck board.
considering the amount of high voltage floating around there, i'd
suggest you fix that first.

if your AV jacks have perfect signal, and you're piping RF directly
into the thing..then, yes, it sounds like you have a defective tuner,
you may try tapping the tuner itself and see what happens. my RCA XL100
console has a tuner issue like that. my GE 36" has a tuner that stopped
functioning, it's basically locked between channels 2 and 3 judging
from the noise i'm getting.

quite honestly, i don't see where analog RF tuners are a necessity.
We've already started moving away from that with DVD players. I've in
fact considered "building" basically a box with a medium resolution
video monitor and then getting the hardware to convert baseband
(composite)/S-video and interlaced progressive signals to native RGB.

"BongBoy" wrote in message
ups.com...
well, tapping on the neck board to get the picture back indicates to me
you've got a tube going bad, or bad solder joints on the neck board.
considering the amount of high voltage floating around there, i'd
suggest you fix that first.



A bad tube won't make snow, but I suppose there might be some strange
arrangement where power for the tuner routes through the neck board. More
likely the tapping is just jarring a loose connection inside the tuner, this
should be easy to fix by just resoldering the bad one.

Very common problem is a bad PLL IC in the tuner SDA3202-2 is the
number and it's an absolute bitch to replace.

In message tLqse.16020$L65.8823@trnddc05, James Sweet
writes

"BongBoy" wrote in message
oups.com...
well, tapping on the neck board to get the picture back indicates to me
you've got a tube going bad, or bad solder joints on the neck board.
considering the amount of high voltage floating around there, i'd
suggest you fix that first.



A bad tube won't make snow, but I suppose there might be some strange
arrangement where power for the tuner routes through the neck board. More
likely the tapping is just jarring a loose connection inside the tuner, this
should be easy to fix by just resoldering the bad one.


He was talking about tapping the neck board solving a blank raster, not
the tuner problem. It certainly does sound like a bad tuner but I'd
check all the voltages first, if it's missing one it could cause this
problem, check the 'net for a datasheet and work from there.
--
Clint Sharp

Thanks Ron, I'll see if I can find a datasheet for this to learn more
about this IC. I'm guessing you mean it's a bitch to replace due to
it's size? Any idae what the component costs?

Thanks for the response Clint. Your right, tapping solved the raster
problem, not the tuner. I'll take your advice and see what I come up
with. This is what I was wanting to know before trashing the set. A new
tuner is $92.00. The set is 17 years old, but really has a good picture
through the A/V inputs. To all I didn't reply to, Thanks for your help.
Again I'm a beginner, and have learned alot from all of you visiting
this group.

again, i'd say chck the solder joints, and if you check the volage,
check it on both sides of the solder joint. many times you'll have
voltage at the solder point, but due a fine crack in the solder, it
loses continuity.

while probably not an issue, make sure when you remove a componet, you
try not to remove the platated throuh holes.

The reason the SDA3202-2 is hard to change is the fact that its mounted
on a small board in the tuner that has metal brackets on each side of
it, and it solders all the way through the board, not just on the end
of the legs, so the only way I know to change it is to have small
snips, cut off all the legs, remove the body of the chip, then with a
very small soldering iron try to heat one leg at a time as you pull
each out until they are all removed, the carefully solder wick the
excess solder off which is hard because it goes clear through the
board, then poke any plugged holes clean with a small needle. All this
is done with numerous surface mount resistors and transistors right
where you are working, so careful going. After all this simply mount
and solder the new chip in and set is fixed 100% of the time. I've done
30 or 40 of these over the years.

Thanks Ron. Iv'e been trying to butter up a tech in my area that owns a
repair shop for some apprenticeship learning by loaning him my LC-101
since his is broke, buying winstips for both of us etc. Long story
short, I told him the symtom of the set and he started to talk about a
chip in the tuner. I asked if it was the PLL, he said yes. I said you
suggested this as a probable fault, and was a mother to change. He told
me exactly what you just typed above. I will take a little of everyones
advice, check for voltages, solder connections, etc. Then will
definitely jump on the PLL, what ever this does (I do know it stands
for phase locked loop). This is why I like this group. Learn something
new everyday. Thanks a ton to all. Will post a follow up soon on
outcome.

OK, now I see what your talking about. This is gonna be a son of a
b*%&h. Now, I had to remove the crystal to get my dikes in there.
Should I replace the crystal since I'm in here, or are these pretty
much dependable long term? Thanks. P.S. I checked with Mouser and the
IC is $11.00. Does this sound high?

If the TV has good pciture through A/V inputs, why not get a set top
external tuner (or VCR) and connect to AV ins. Beats replacing the
tuner (and paying $92 on a 17yr TV).

On 17 Jun 2005 03:13:33 -0700, wrote:

Thanks Ron, I'll see if I can find a datasheet for this to learn more
about this IC. I'm guessing you mean it's a bitch to replace due to
it's size? Any idae what the component costs?

It's the position...you have to cut pins on the IC, etc., to get it
out, and too much heat can easily ruin some solder pads...if I
remember correctly.

Tom

On Fri, 17 Jun 2005 21:37:51 GMT, Tom MacIntyre
wrote:

On 17 Jun 2005 03:13:33 -0700, wrote:

Thanks Ron, I'll see if I can find a datasheet for this to learn more
about this IC. I'm guessing you mean it's a bitch to replace due to
it's size? Any idae what the component costs?

It's the position...you have to cut pins on the IC, etc., to get it
out, and too much heat can easily ruin some solder pads...if I
remember correctly.

Tom

Hmmm...double-sided solder also?

Tom

On 16 Jun 2005 12:22:42 -0700, put finger to keyboard
and composed:

I have a magnovox model #RJ5540-AK01 that only picks up snow and no
sound on all channels. The cable connection is good (from a sattelite).
Set initially had only black raster, but now has decent brightness
since tapping on CRT neck board. The rear A/V jacks give a perfect
picture and sound. I suspect a bad tuner, but how can I determine if
the tuner is bad, and is there another suspect compenent I can check. I
am a beginner and have only been working televisions for about 1 year.
Thanks group for any suggestions.

I don't have any experience with your particular set, but here are
some general tips.

Meter the tuner's pins. It appears that your tuner is getting power
(B), otherwise you wouldn't see snow, just a white or black screen.
Check that the band switching pins (BU, BH, BL) respond to band
changes (UHF, VHF high, VHF low). Also check that the tuning voltage
(VT) increases and decreases smoothly as the channels are scanned.

See the bottom RH corner of this page for a typical pinout:
http://www.wagner.net.au/Catalogue/03_01.pdf


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

"RonKZ650" wrote in message
ups.com...
Very common problem is a bad PLL IC in the tuner SDA3202-2 is the
number and it's an absolute bitch to replace.


But he said tapping fixes it, I've never seen a vibration sensitive IC
before.

In message ePKse.20669$2K4.10277@trnddc08, James Sweet
writes

"RonKZ650" wrote in message
oups.com...
Very common problem is a bad PLL IC in the tuner SDA3202-2 is the
number and it's an absolute bitch to replace.


But he said tapping fixes it, I've never seen a vibration sensitive IC
before.
No, he didn't say that, he's stated twice now that the tapping only
cured the no pic fault. Once he'd got the tube working then he
discovered the tuner didn't work. BTW, I have seen a vibration sensitive
IC, must have been a bond wire or something but it was an EPROM which
'looped' back to 0 intermittently when you were trying to read above
0x03fff. Tapping the chip would cause the problem to appear more
frequently and could be demonstrated in a little test jig we threw
together because it was such an unusual fault.



--
Clint Sharp

Clint, again you are right. I tapped the board on the picture tube neck
to get raster. I have checked tuner voltages and I seem to have all of
them. I ordered the PLL ($11.00). Will try this per Ron's advice since
nothing else found wrong. I did get the old one out without damage to
the surface mount components I hope. I need to add that I didn't
exactly have a totally black screen. I could barely see snow in the
picture, but pretty much black screen. I have since re-soldered
everything on the neck board, so we'll see if this works. Thank you to
all that have replied. Nice to communicate with professionals. Will
post a follow up when component gets here and installed.

No, he didn't say that, he's stated twice now that the tapping only
cured the no pic fault. Once he'd got the tube working then he
discovered the tuner didn't work. BTW, I have seen a vibration sensitive
IC, must have been a bond wire or something but it was an EPROM which
'looped' back to 0 intermittently when you were trying to read above
0x03fff. Tapping the chip would cause the problem to appear more
frequently and could be demonstrated in a little test jig we threw
together because it was such an unusual fault.



Oops, I missed that. Yeah it could certainly be a bad tube, but try
resoldering the neck board first, it's easy. If it still has that symptom
then just scrap it.