TV and television

Nov 8 04:23 UTC 1997

For discussion of television hardware.

response 2 of 27:

Nov 10 12:21 UTC 1997

r.e. option 1:  Don't use a tap.  Use a signal splitter / amplifier
-splitter.  Otherwise you muddy up the impedance waters.
 
If you have audio and video sources for all the things you want to send
to your satellite TV, the satellite is not going to move around much and
it is not difficult to run the coax to it, I'd go with option 2.
Modulators are pretty cheap and work pretty well.  Otherwise there is
always option 3.  I have also seen TV signal X-mitters that operate
on channel ~14 and can X-mit a couple hundred feet.

response 4 of 27:

Nov 11 12:28 UTC 1997

As I have the Jameco catalog in fron of me, I see they have a "Video
Transmitter Station" that X-mits on channel 7-13.  It includes the audio
and video input cables, has a F-connector on the back should you want
to X-mit to the entire neighborhood, a telescoping antenna for local
X-mitting, a built-in test pattern switch, etc. all for $45.  Home Auto-
mation catalog also has such devices in it, I'm sure.

response 6 of 27:

Nov 12 12:38 UTC 1997

I'm confused than.  Your option 2 said something about feeding audio/video
(I assumed that you meant line-level audio/video signals here, not RF)
from the VCR to a modulator.  That is what this is, except this A/V
modulator has a much higher RF output such that you can forgo the coax
connection between the modulator and the satellite TV and use their
antennas instead.

BTW, the little $5 Jameco A/V modulator will allow you to feed line-level
A/V signals into your satellite TV that doesn't have line-level inputs.

response 8 of 27:

Nov 13 12:57 UTC 1997

If your new TV has line-level inputs, it may be worth your while to 
connect those to your VCR and experiment with what comes out of the
VCR line-level outputs.  My experience has been that whatever is on
the the F-connector is also on the the line-level jacks when in play-
back, record and when you are using the VCRs tuner to display TV on
a monitor.  When the VCR is off, rewinding or in playback, the RF in-
put is connected to the RF output.  This way you can insert a VCR into
the the coax that feeds your TV without it interfering with the
operation of the TV when it is off. Yet you to play tapes to the
TV simply by pressing the play button on the VCR and switching to
channel 3/4 on your TV.
 
You can also use your VCR as a tuner as well as a VCR if you use your
new TV (The one with line-level inputs) as only a monitor.  The RF
signal would go to the VCR RF input and the VCR line-level outputs
would go to the line-level inputs of both your new TV and your video
modulator which X-mits the signal to your satellite TV.  A line-level
output is capable of driving at least two line-level inputs so you can
use a simple Y adapter to split the signals.  This would allow you to get
by with only one remote too.  (I have used a similar setup at home for
years.  I could have saved some money by getting a TV without a tuner ;-)
With this setup you can play tapes to both TVs or show a given program,
tuned by the VCRs tuner, on both TVs.

response 10 of 27:

Nov 14 18:29 UTC 1997

You are correct. The VCR tuner signal is on the line-level output if one
is not running a tape. I disconnected the RF VCR output, and could play
both TV and tapes (as expected) from just the line-level input to the
TV. So, a modulator-xmitter would do just fine. Would it be better to
use the Jameco unit that xmits to ch 7-13, or the one that xmits to
UHF channels? The satellite TV has the usual discrete tuning for VHF
ch 2-13 (with 'rabbit-ears'), and continuous tuning for UHF (with the loop).

I tried lots of combinations last night, including disconnecting the RF
feed to the TV, and learned a lot, but also got myself rather confused,
what with VCR options of off, on with choice of "TV/VCR", and tape, and
TV options of TV/VCR, and the choice of control of either the VCR or the
TV from the same remote....I often didn't know where I was! 8^{

[Is anyone else following this thread - and getting confused too?]

response 12 of 27:

Nov 17 16:55 UTC 1997

I've ordered the Jameco unit. Will report.....

response 14 of 27:

Jan 5 17:02 UTC 1998

TV REPAIR - Help needed
I've got a late model TV that has lost the lower half of the picture and
displays it as a 1/4 inch bright band across the center screen, while the
upper portion is displayed as a few dozen lines expanded vertically filling
the rest of the screen.
Can someone recognize this problem and give me direction.  It's not worth
taking to a repair shop, but if an inexpensive part is the cause I'd like
to fix it.  Adjusting the height pot had no effect.  
Its a 1990 Toshiba CF2044J....any ideas?

response 16 of 27:

Jan 12 05:20 UTC 1998

I would suggest opening it up.  DON'T TOUCH ANYTHING.  Besides the high
voltages during operation the inside of the tube acts as a capacitor that
holds eough energy to really hurt you or even kill you if you discharge it
the rwrong way.  Now under bright light and maybe with a magnifying glass look
at every detail of the board to see if you can spot where a component failed
by making a lot of heat and burning itself up.  This will give you a good idea
what area to look for the real problem.  I'll guess that it's a cap that lost
it's open circuitness.  You can then carefully unsolder it and replace it with
an equivalent.  I did this with a monochrome monitor for a leading edge XT.
It is now perfectly fixed, still worthless, and the medium through which I
am typing this very message.  If there is interest, ask about what parts hold
that big charge and we'll try to describe what not to touch.  :)

response 18 of 27:

May 15 17:32 UTC 1998

Thought I'd post this on the odd chance it might help someone else out:

I recently got an RCA X100 19" TV for $3.  It had a slightly shrunken
picture that refused to sync up.  Whacking the side of the set would bring
changes in the pattern and bring the sound in and out -- classic symptoms of
the dreaded RCA Crappy Solder Joint Syndrome.  I took it apart and prodded
at the board with a plastic pen (with the set running) until I found the
'sensitive' area, then resoldered all the joints around it that looked bad. 
Powered the set up, and the picture still wouldn't sync.  Tapping it no
longer changed things, though.  Hmm.  Gee, those joints I resoldered were on
the controller IC, I wonder....put it in service mode, and the picture
suddenly synced up.  A little tweaking of the rather confused service mode
settings soon got me a beautiful picture. :) The TV works perfectly now and
is almost new.  Not bad for $3. ;)

response 20 of 27:

Jun 4 17:31 UTC 1998

What are the differences between the bands and modes for cable and broadcasts
television? 

response 22 of 27:

Jun 13 05:34 UTC 1998

I have obtained an ALPS QBBT452 video-RF modulator (for converting a
composite TV signal so I can watch it on a portable LCD TV that has no
composite input). It has a phono-jack for "to VTR TU". What is that?
It also has three (3) pins, ostensibly for video in, something called
"MD. +B", and Control. I guess "MD. +B" is the power supply line (case
ground). But which pin is which (before I fry something....)? 

response 24 of 27:

Jun 13 18:47 UTC 1998

That what I thought (being from the "olde tube era" - but I didn't
expect to see it on a solid-state rf unit. Your suggestions for VTR and TU
are reasonable - that's what that jack is for. Now...what about "MD",
"Control", and...which pin is which?

I found ALPS on the web, but not for components - just for computer interface
devices. I have inquired of All Electronics (maybe they sent me the
wrong spec sheet). 

Incidentally, "B" in the olde tube era didn't mean "battery". Battery
suuply was divided into "A" for filament batteries, "B" for plate batteries,
and "C" for grid batteries. One doesn't find "B" batteries any more. You
can still find "A" style batteries, even though there are no "filaments",
and it is possible that the "C" battery notation got carried over to the
C *size* battery.