I used 25.75 MHz on my 721TS to feed the modulated IF signal into the tuner. I did have to add the manual IF/RF toggle switch because the VA62 function switch outputs RF (microvolt) level when in the TV RF channel positions. The EPROM defaults to 25.5MHz, due to my misunderstanding when I did the programming. Here are the steps to get a modulated 25.75 MHz IF signal to drive the IF/detector stages:
1. set the RF/IF - SIGNAL function switch to PROG CABLE
2. enter 42 on the keypad, because I only reset channel 42 to 25.5MHz
3. press the +/- to program the offset frequency
4. press 025 to tell it to add 0.25 MHz to the 25.5 to get 25.75MHz
5. Set the manual RF/IF toggle switch to the IF position to get millivolts of output
6. Use the RF-IF LEVEL and RF-IF LEVEL VERNIER to set the output level you need.
7. Third IF input needs higher level, second less, and first less due to the amplification of the IF stages.
8. Set the VIDEO PATTERN to the test pattern you want modulated on the IF signal output from the VA62.
Dave
Link to RF/IF manual switch mod:
http://videokarma.org/showthread.php...ht=va62&page=3
Its really hard to see, but in the pictures you see a hand drawn switch diagram followed by two pictures of the back of the front panel. I added the manual RF/IF level toggle switch between the AUDIO and RF-IF LEVEL rotary switches.