lordsmurf, The black levels on the TBC really depends on the unit per say. Sometimes it is fixable and other times it is just the machine. The AG1980P differs from the AG 1980. Some of the capacitors are molded in to a medal plate and you can't remove them. The 1980 tends to be a lighter picture than the 1980P decks. When you turn on the units and get a humming noise that is bad caps. The dim display is faulty caps usually in the power supply and around the front panel. The units are getting harder to fix, my costs have gone up big league. As I have stated many times when the machine is really off, you get some random noise in the picture. Because of the age and that Panasonic used a poor string of caps and resistors, you are going to have to get them refurbished.
The shops that can do them are in short supply and most techs will not waste hours upon hours trying to figure these machines out. Sometimes they will attempt to repair them say they are fixed and they are not.
The color levels on each unit tends to differ from machine to machine. With the wearing out caps you lose a lot of the color it tends to fade out. The JVC 9800 has very bright colors levels and the 9900 in my opinion has the perfect blend of colors.
Again the AG-1980's are hit or miss, that is even when they are fully fixed. They never play the same.
Of course if you press stop and play you will get a slight shift. This can be seen with reds.
The AG-1970 doesn't have a video card either they tend to play more the same than the AG 1980's. Just about every time going in to the 1980's you have to rebuild the video card.
On the last few units that I worked on found loading problems and than the heads were also kind of worn. On one of the machines I could not get a picture until I scrubbed the heads this took a long time. Have two machines I am working on, both display a blackish picture and need tons of capacitors replaced.
What really sucks for the consumer, you have no easy fix to rebuild these units.
Just tested my unit with the TBC on/off, it is just a tad bit darker with the TBC. The unit I have is perfect took the best of the lot.
On a side note, got a home recorded copy of an NFL playoff game from 1980 and TV back in 1980 was not great so what I did was hooked it through an external TBC and messed around until I got the color levels to how I wanted them. It is just a thought.
Last edited by deter; 10-22-2018 at 11:44 PM.