Montgomery Ward (Sylvania chassis, OEM NAP) Tuner Trouble

[liammc00]

Originally Posted by old_tv_nut

If you're getting snow like that, it seems the tuner and IF amplifier are working.
Guesses: May be a problem with AGC or sync (which could be on the same module as the IF), or a connection between modules, or a ground connection.

IC601(NTE1413) in the IC functions in the Sam's it says that IC601 does these things sync demod, IF amplifier, AGC DET/Noise INV, White Spot Inverter, video preamp, AFT sync demod, and REF amplifier. I did test the voltage on the pins that the Sam's (2660 folder 2) in troubleshooting the IF/AGC with a signal attached from a VCR out putting a blue screen as my signal. I did mark the adjustment pot for the RF AGC and no matter were I moved it. The results were barley noticeable after that I put the pot back at the factory spot.

Results:
Pin 3 .7v the Sam's says .6 volts
Pin 4 11v the Sam's says 4.7volts ( 4.5 -11volts ) RF AGC range
Pin 14 12v the Sam's says 7volts ( 6.7- 11volts ) IF AGC range
Some other pins were reading not what the schematics said they should.
I will go and check the connection between the modules. Also I will check the grounds as this TV has had bunch of cold solder joints I had to fix.