4dtv dsr920 Receiver RCA output

[rodin]

I am trying to watch C-SPAN on C3 TP 7, and able to receive a nice clear picture, however, it is jumping real bad on 3 seperate TV's. The best way for me to explain it is like the old VHS Days - when you tried to make a copy of a VHS to VHS tape, the picture would fade, roll, jump, go bright, dark, fade, roll, etc. C-SPAN doesn't have encryption nor copy protection, and tried it on our other receiver in another office, and it appears to work fine. Any suggestions on what could be wrong on the receiver? This occurs on all channels (Analog, haven't tested any Digital Channels). Any help would be most greatly appreciated

 

[sergei]

What happens when you only have one TV hooked up to the receiver?

 

[Lak7]

Is the Channel Quality jumping?

 

[tvropro]

If your splitting the composite video out to 3 tv's with out a buffer amp with DC clamp it's going to tear all over the place. Your changing the termination resistance of 75 ohms and causing it to loose sync. You can only connect one tv at a time to an RCA composite out unless you use a buffer amp. I know all about this since I have designed and built video buffer amps, once AC capacitor coupled at the input they must have the DC reference restored before amplification of each output.

 

[14karat]

The VHS copy issue was due to Macrovision protection which scrambles the sync pulse on the output which, in turn, jacks up the gain control on the receiving device.
I doubt any relation here. It sounds like interference of some sort.
Based on the thread title you're using the RCA outputs... have you tried using the regular TV out (coax - rg59/6?)

 

[14karat]

TVROPRO is right -
Can you clarify '3 separate TV's'

 

[rodin]

Sorry folks for the confusion -- 3 seperate TV's all conntected only 1 at a time to the receiver for testing, not all 3 are connected at once.. Going straight from the receiver straight to the TV

I haven't tried using the coax output due to the lack of a/v quality.

Channel Quality and Signal Strength are all stable.

Thanks all!

 

[tvropro]

Sorry folks for the confusion -- 3 seperate TV's all conntected only 1 at a time to the receiver for testing, not all 3 are connected at once.. Going straight from the receiver straight to the TV

I haven't tried using the coax output due to the lack of a/v quality.

Channel Quality and Signal Strength are all stable.

Thanks all!

If that's the case there is a problem in the 4dtv's video circuit loosing DC reference.

 

[rodin]

Thanks! If I only knew which capacitor to change out, lol. Anyone know on a GI DSR920 where the electrolytic capacitor is on that board - Assuming that would possibly be the problem?


Thanks for the help!

 

[tvropro]

Thanks! If I only knew which capacitor to change out, lol. Anyone know on a GI DSR920 where the electrolytic capacitor is on that board - Assuming that would possibly be the problem?


Thanks for the help!

It may not be a cap, if its loosing dc reference it's probably a diode or power supply problem. If you have an oscilloscope and know what a video waveform is suppose to look like you can scope out the problem.