Quote:
Originally Posted by Chris K
Ok I will forget about the tone. I’ll answer your questions one by one…The VTVM is set to AC and the range is set to 5V as you said.
The 250K pot is in place and the voltage at R135/136 was adjusted to -4.5V DC
When I have fed a video signal through the antenna from my pattern generator I get an image. The multiburst pattern is ok but the high resolution bands are not sharp. Anyway I’m assuming this means the video IF circuit is working?
The AC probe of the VTVM is connected to pin 1 of V106. The needle on the VTVM does deflect sharply to being pegged if I raise the frequency on the 8601. I get lost with what you say after that. Should I slightly mistune the generator and then do something after that? I got confused because you started talking about signal gain and levels and not changes based on mistuning.
|
If you swing the generator away from 21.25MHz and both sides the amplitude increases, then the trap is working. Remember there are two 21.25MHz traps.
You may have to raise the RF signal at the trap frequency sufficiently until you see the nedle deflect. I am only suggesting you slightly swing the generator away from 21.25MHz to test for the trap presence because the trap will cause a big dip. It seems that you are not applying sufficient RF at 21.25MHz to make the adjustment.