|
Well, getting to the alignment did take "a while." Got a 2500 ohm 100W resitor to load the B+ with the sweeps disabled, read the procedure in SAMs and RCA about 10 times each, then realized I had to make some cables that were missing from the B&K sweep gen I bought on the bay.
Finally fired up everything today and started the sound alignment and video sound trap. Discovered the B&K will produce modulated IF marker frequencies, but not the modulated 4.5 MHz called for in the old procedures. No problem aligning the sound IF and detector, as there is an alternate procedure for doing it with a sweep. However, the video sound trap (actually a 4.5 MHz trap in the chroma take-off coil) only has a procedure for using 400 Hz modulated 4.5 MHz. So, I tried it with the sweep instead, and I hope I got it right, because it looked like the trap frequency was off quite a bit low. It was hard to see, though, because the chroma board is crawling with 3.58 MHz CW. [doh - just had a thought - before I tear down, I should see if I can kill the color oscillator temporarily - will have to try that] A wrong trap frequency could have something to do with the color ringing I have seen on color bars, but I really want to make sure I haven't screwed it up.
Next after the audio is to get everything connected for aligning the IF, which the B&K is fully capable of, even the procedure that uses CW at various frequencies and then checks the overall result with the sweep.
|