Can someone help me adjust the geometry on my CTC-186/7 ?

[kcollins4]

Hi guys,
I'm out of my element adjusting a TV. Spend all my time in the vintage audio forums. We recently bought a used Sony 34" XBR (2007 model), and moved our old GE CTC-186 to the bedroom. I was going to adjust the focus and brightness, but they're really pretty good. However, the geometry of the picture is "off". The bottom corners are a bit stretched out, cutting off the left and right letters or numbers on the screen. Also, the vertical size has grown enough that a sentence at the top or bottom of the screen is only partly visible.

After poking around the web, I've found how to access the service menu, but have found no mention of what values and parameters I should enter to adjust geometry. I realize playing with the service menu is dangerous, but I'm confident with some AK help, I can have a better picture. Any advice appreciated.
Thanks

[radiotvnut]

Has this set had the tuner grounds resoldered? If not, I'd suggest doing that before adjusting anything in the service menu. You'll need to unsolder the bottom tuner shield and resolder all of the ground tabs on the tuner shield. These grounds develop poor connections and can cause all sorts of problems, including corrupting the eeprom.

[MRX37]

vertical height stretching? Start checking caps in the vertical circuit.

Really your geometry problems could be due to some lytic caps drying out.

[kcollins4]

Thanks for the input, folks. If it needs to be recapped to improve the problem, I'll just live with it. I assumed there would be geometry adjustments. Thanks again. Guess that can't be done.

[MRX37]

Recapping isn't that hard if you know basic electronics.

It's just finding the offending caps that'll be annoying. Still shouldn't be too hard, especally with the people here knowing as much about various CTC chassis and whatnot.

[Duane]

It's hard to believe that a 2 year old set would have cap problems,but then who knows with these Sony sets.Which 34" set do you have?

There are several adjustments that are available in the service mode of your Sony. Some of the these have to do with overal sizing of the picture,others deal with bow and pincushion,linearity and so on. Two of the easiest parameters that could help you are VSIZ and HSIZ.

You might want to invest in a service manual for your set. It will have all of the parameters and their original values plus how to access the service mode.

One good thing to have before you do anything is to buy,borrow a test disc with test patterns that are used specifically for geometry. Video Essentials is a good one to use.The crosshatch is the one to use.

There's a caution about entering the service mode. You can cause some major problems with your set if you start changing things without knowlege of what it is you're changing.

[Duane]

Please disregard my statement above....I saw the Sony set mentioned and really got sidetracked. My appologies.

[Ed in Tx]

Oops me too! Started to offer service info on the 34" Sony! I know nothing about the RCA.