View Full Version : Bigscreens


fujifrontier
10-14-2007, 06:09 PM
Anyone work or like to tinker with bigscreens?

ChrisW6ATV
10-14-2007, 06:39 PM
I have worked on a few rear-projection CRT sets. I replaced a bad blue CRT in one, that had a bad burn from collapsed vertical sweep. Others, I have done basic things including cleaning the mirrors and CRT faces.

fujifrontier
10-14-2007, 09:16 PM
My grandma's Maggie needs its coolant changed... if she gets a new TV i think i will try it, just for the fun of it.

dr.ido
10-15-2007, 01:19 AM
I haven't had much luck with projectors so far. I bought a Pioneer video projector that I though was a front projector, but I was wrong. It was part of a video wall and the lenses were fixed focus for a 42" picture. Without the mounting frame and screen it was useless.

I've worked on a couple of rear projection sets the most recent being a HD capable 46" Philips. I replaced the convergance IC that was shorted and got it working again, but I couldn't get the focus and covergance good enough to produce a picture I'd be happy with.

I've passed on a couple of old front projection sets with curved screens. If I had the room I'd probably have grabbed them for novelty value, but even in perfect condition I doubt I could use one for regular viewing.

andy
10-15-2007, 01:22 AM
I used to fix a lot of these, but I can't say I really enjoyed it. They took a lot more time to fix and had a much higher return rate than regular TVs. About half the Magnavox sets I repaird belw the flyback within a few weeks.

radiotvnut
10-15-2007, 11:26 AM
I never have cared for or had much luck working on big screen TV's. I just tossed a late '90's Zenith because I was tired of it sitting around. I replaced the HV splitter in an RCA PTK179 and the power supply & horizontal parts in an RCA PTK169. I did replace the HOT in a friend's Magnavox bigscreen and I think it's still going after 10+ years. I have a mid '90's Sony 46" in my way right now. It was a gift from the TV shop and the standby light blinks constantly all the time. This set was said to have been hit by lightning. I just have not gotten motivated to work on it and I may not get motivated. Bigscreens are too hard to move around and I have to find someone with a truck when I do go get one. If I was to sell one and it failed within two years; the buyer would be on me like white on rice. I've now made a rule: No bigscreens, PERIOD!

kx250rider
10-15-2007, 01:36 PM
They're terrible overall. Big, heavy, and always have callbacks. The only exceptions might be the RCAs of the 90s; the PTK-169 series. Those usually had OK CRTs, and would "stay fixed" awhile. Easy troubleshooting too, as a rule. Maybe the early-mid 80s Mitsubishis were OK to work on too, but they would always have dim CRTs after a couple years. And that brown glue to hold the wires on the board that turned hard, CORROSIVE AND CONDUCTIVE!!!!!! I guess the convergence chip failure, which was usually an easy $200 profit fix on Mitsubishis, makes up for the brown glue fiasco. And let's not forget the 80s Mitsubishi yoke insulator boots turning from soft rubber into hard, cracked crap that would corrode and start a fire in the yoke. An easy fix, and I was able to do the whole job including full convergence within 30 minutes! I made special 2x4 wood blocks to hold the CRT chassis just high enough to slip the yokes off the necks. I did 100s of those. Once in awhile I'd find a hole in the CRT neck, but that was rare.

Sonys always had shorted CRTs after hours of troubleshooting, and they would spew fluid all over the boards. Hitachis and Hitachi-based RCAs were reliable and not too hard to work on, but they had 2 mirrors and were horribly dim & blurry. Pioneers were TOUGH to troubleshoot, and eventually I refused to service Pioneers. Probably the very worst of the worst was the 90s Magnavox and Zenith. I can't comment on those without using inappropriate language.

I worked on probably 1000 projection sets, and I'm glad I don't have to anymore :)

Charles