Video inputs Tube TV

[ARC Tech-109]

Progress update. Had a weird and uncommon failure in the 3.58 osc section, the xtal tuning coil literally shorted out. The little dab of wax used to hold the wires across the coil form dissolved the enamel and shorted the windings killing the color and giving me a good week of headaches chasing this one down. At first it was lost color sync then a fade to gray, it acted like the color killer was coming on so that's where I focused until I looked at pin-7 of the 6HS5 and found chroma and the osc, when I bumped the tuning coil the color flashed and that's when I looked closer and found the wax flaking with some green enamel missing.
My fix was using some fine wire from a small audio transformer and winding a new coil, once I had it on frequency it was dabbed with a touch of Testors model adhesive. Not a common repair for sure but my odds of finding another coil is around zero.

[ARC Tech-109]

So more progress has been made. Ditched the 12AT7 based video input amplifier in favor of an LM1252 video op-amp and basically rebuilt the entire interface board. It still retains the LM1881 sync separator as this has been a real asset when dealing with non timebase corrected videotape sources as I get no flag waving or skew induced distortions. The amplifier has an overall gain of 5 at 75 ohms and this is then padded using a pot which then feeds the pentode grid of the 6MU8 1st video amplifier. Below are a few images of the amplifier and actual raw playback from a tape I made the spring of 1985 using a Sony VO-2600 I bought from a surplus store for $20.00, sorry for the rather poor capture quality. Every time I try to use the Pro camera mode it seems to make things worse and no matter how I try it is never quite right.

Video Interface board: https://imgur.com/T1S6xpU

Tape Starting Point: https://imgur.com/hco1PnH

Actual Screen Capture: https://imgur.com/dUCnGtM

Sony VO-2860 In Action: https://imgur.com/stVHm2b

[kf4rca]

You mean LT1252.
https://www.analog.com/media/en/tech...ets/lt1252.pdf
Yep, I would have gone the solid state route also. BUT, it depends on what type of power supply you have available.
Another video chip that's cool is the AD828 from Analog Devices:
https://www.analog.com/media/en/tech...eets/AD828.pdf
It has high output drive capability and flexible power requirements.
Some time ago, Motorola had an application note called "the last 10 percent" which discussed the issue of "flag waving."
The problem is that the horizontal AFC can't follow the pulses as the signal goes thru vertical sync which are broader than horizontal pulses,