|
If the contrast control's range is too far in a given direction look for a control marked AGC and try adjusting it. The AGC (Automatic Gain Control) controls the signal gain of the IF and tuner such that the signal these deliver to the tuner stays at a consistant level, thus eliminating the need to readjust the contrast when switching between weak and strong broadcast stations. It works on a feed back principal where it measures the synch pulse level (which should not vary) in the video signal and adjusts the gain of the tuner and IF to hold that synch value at a constant level. adjusting the AGC control adjusts the level of synch (and the video signal which contains the synch) that the circuit tries to maintain. A misadjusted AGC can either overload the video and synch blacking out the picture or wipeout the video (the synch tends to go first) causeing a blank white screen. The AGC may also affect the synch of the deflection circuits if an overload occurs so it could simultaneously be messing with the contrast range, and upestting the vertical synch as you have described.
On the "reaching" blue problem if you can get a source (ie. testpatern generator, testpatern recordig) for a white cross hatch on a black background then play it on the set and if the bars deviate from pure white, and have either a color fringe or a parallel bar of any of the three screen primary colors then that indicates that the blue issue is a convergence problem which can be solved by preforming the convergence adjustment procedure (convergence is complicated and takes some time to get good at, but one can probably pick it up over the course of a week end).
I believe that your set uses a newer inline gun type CRT which has a different procedure from the deltagun CRTs I'm used to converging.
In your shoes I'd save the SS board too as it is cool to have both versions. What I meant to say was that it is not worth it to save inline gun CRT SS (Solid State) sets unless there is sentamental value attached to a certain set or it is historically signifficant in some way (like the first SS set from a certain brand or the first example of some feature or circuit).
Hybrid sets were made for two reasons. One to save cost over using transistors in a given circuit. And two to use up excess stocks of tubes. Both reasons ultimately boiled down to trying to make the sets cheaper to gain a market edge.
I always love to hear of those oddball later hybrids.
You have got a very cool set there. I'd save one of those any day of the week (though hybrids don't show up much locally).
|