|
|
|
#1
11-26-2008, 12:56 PM
|
|||
|
|||
|
RCA CTDC185A3 bad focus around the edges of the screen.
I've been working on an RCA CTC 185A3 TV that was thrown away because of a broken coax input. I noticed that the corners of the screen wern't as sharp as the middle of the screen. Initally I thought it was just bad convergence, but upon getting a test pattern up on the screen, it seems the actual focus is bad around the edges of the screen.
The middle of the screen is nice and sharp. Adjusting the focus control on the flyback helps the middle of the screen, but not the edges. 
|
|
#2
11-26-2008, 01:01 PM
|
||||
|
||||
|
Sounds like a weak CRT, Can you test that one?
__________________
My TV page and YouTube channel Kyocera R-661, Yamaha RX-V2200 National Panasonic SA-5800 Sansui 1000a, 1000, SAX-200, 5050, 9090DB, 881, SR-636, SC-3000, AT-20 Pioneer SX-939, ER-420, SM-B201 Motorola SK77W-2Z tube console McIntosh MC2205, C26 
|
|
#3
11-26-2008, 01:08 PM
|
||||
|
||||
|
The focus (G1) control doesn't change the edge focus at all? Even for the worse? If so, I'd also think the tube is weak or maybe the focus voltage is low. Unlikely the latter though if center focus is strong.
|
|
#4
11-26-2008, 01:11 PM
|
|||
|
|||
|
Quote:
The CRT still has a lot of brightness left on it. There's no color bleeding when brightness is at normal, or even when its high, but when I turn the G2 DOWN, color bleeding starts. That's another mystery, as color bleeding usually happens when the colors are brighter, not dimmer. At normal brightness, turning the color up to max won't produce color bleeding. However, turning the brightness down will produce color bleeding even with the color at normal levels. EDIt" the G1 control can certainly make the edge focus worse.
|
|
#5
11-26-2008, 01:14 PM
|
||||
|
||||
|
Thats a pretty good sign that something's wrong in the video output circuits or the crt itself. By turning the g2 down you are causing the guns to cutoff at a lower point which they can't handle.
|
| Audiokarma |
 |
|
|
Linear Mode
