old Sony trinitron


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old Sony trinitron

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EMUGOD
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Jul 16, 2007, 1:59 AM

Post #1 of 16 (4199 views)
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old Sony trinitron	Can't Post

I have this relatively ancient (from the 80s) Sony Trinitron. I sadly do not know the model number (it was originally on a foil sticker on the back, which is long gone), or i would go to Sony for help.

it has been in the family since it was new, and has recently had some problems with the color getting... weird. I did some research, and the symptoms do seem to fit a purity problem.

so, i have it open, sitting on the floor. i have found the ring magnets that control purity, i think. there are six total, 2 marked (by a sticker on the inside of the case) for purity, two for "V. Stat", and two for "BMC". the question i have, is what "BMC" and V. Stat" stand for? i tried just changing the purity settings, but couldn't get it back to normal.

also, and i know this is unlikely, is there some sort of standard way to bring up a pure white raster? i am going to try to hook up my game console, and use its photo function to show an image i made on the computer (of a completely blank white screen) in full-screen mode, but i am worried that the game console might change it and make it not actually pure white, thereby screwing upthe effect (however slightly).

thanks in advance for any help! <br>

(This post was edited by EMUGOD on Jul 16, 2007, 2:04 AM)

rrobor
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Jul 16, 2007, 9:35 AM

Post #2 of 16 (4190 views)
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Re: [EMUGOD] old Sony trinitron [In reply to]	Can't Post

These are static convergence controls and if you keep your hands off them the will be in the correct position. A static control is just that, a fixed magnet, screwed and glued for life. What is normal with Sony TVs is they need fully switched off for a few hours every so often. People tend to leave them in standby and the purity drifts out and as you dont switch off the set does not degauss.

RetiredTVguy2
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Jul 16, 2007, 4:12 PM

Post #3 of 16 (4182 views)
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Re: [rrobor] old Sony trinitron [In reply to]	Can't Post

Yep! those controles should not be messed with. Anyway what size set is it? Give a discription of what the pic looks like. Does it have "blotches" of color, perhaps in one corner? Then degause. Or does it look "washed out" like dull whites and grayish looking blacks? How about the green? Is there an overall greenish tint?
If any of that I would have to guess a bad picture tube, does it blink at first start up? Tel-tail sign of a bad CRT.
Don [retired]
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When everyone treats you bad, turn to your dog, he or she will understand!
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I dont mind working, as long as it doesn't interfere with fishing!

EMUGOD
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Jul 16, 2007, 9:27 PM

Post #4 of 16 (4174 views)
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Re: [EMUGOD] old Sony trinitron [In reply to]	Can't Post

i've pretty much nailed it down to being a purity problem. in fact, i am certain. i have already been messing with them (the ring magnets), and have been able to clear it up a little, but no where near enough.

there are blotches of discoloration in all four corners, and in 2 or 3 rounded rectangles in the center of the screen. most of the screen is discolored, at this point.

i am determined to see this project through to the end, and honestly, if the tv is destroyed it's not the end of the world. so, does anybody have any info about either of my first two questions? what V.Stat and BMC are, or if there is some general way to bring up a pure white screen?

i have already tried cycling the power, it had a noticeable affect, but the discoloration came right back after a few moments. it is a 28" TV.

also, i'm pretty sure the magnets are meant to be adjustable. there is a handy sticker on the inside with a semi-exploded view that labels pretty much everything (the level of detail is so deep it is almost undesirable), and anything that isn't adjustable is marked as such. they also have knobs to grasp them by, and i have read elsewhere that they can be adjusted.

rrobor
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Jul 17, 2007, 12:41 AM

Post #5 of 16 (4163 views)
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Re: [EMUGOD] old Sony trinitron [In reply to]	Can't Post

You ask for advice then you dont take it. These are static controls . Fixed magnets they can not go out of adjustment. Now what you have done is to try to solve a dynamic fault by moving these magnets, sure it will alter it but you are altering it away from its correct position and will never fix it like that. If you can put them back to their position then check your degauss circuit because that is your fault. From an easy fix you now have made it difficult. Perhaps your little knowledge on the subject is not a good thing. these things are only moved to set a new or replacement tube, never to fix a fault.

Paulpablo
Enthusiast

Jul 17, 2007, 1:05 AM

Post #6 of 16 (4161 views)
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Re: [rrobor] old Sony trinitron [In reply to]	Can't Post

Take that good advice and run with it!

HiTech
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Jul 17, 2007, 1:06 PM

Post #7 of 16 (4153 views)
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Re: [EMUGOD] old Sony trinitron [In reply to]	Can't Post

Well said rrobor. If the original poster would have simply tried a manual degaussing of the CRT before removing the cover!!! A Trinitron is the last tv on earth that folks should be experimenting with regarding the purity magnets and such!! Unsure

EMUGOD
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Jul 17, 2007, 10:30 PM

Post #8 of 16 (4146 views)
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Re: [rrobor] old Sony trinitron [In reply to]	Can't Post

so, no one is going to answer either of my original questions? i really doubt you know where the degauss circuit would be? i can set them back in the correct position easily, but again, i am pretty certain it is a problem with the purity, and i am certain that those ring magnets are meant to be adjustable.

rrobor
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Jul 18, 2007, 9:25 AM

Post #9 of 16 (4137 views)
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Re: [EMUGOD] old Sony trinitron [In reply to]	Can't Post

For Gods sake man think. Put those magnets back, How can that help you. You have had some stray magnetic field stuff up your TV, can a fixed magnet fix that , obviously no. Think what can be achieved by fixed magnets, and think if this earth is going to change its magnetic field in the near future. If the answer is no, then ask yourself why you post here and ask questions as you do. You tell techs who have been in this trade as long as colour TV has existed and you tell them how the thing works. No sir you dont think , your Physics are crap, You asked for advice, you got a reply which several told you was valid yet you go on in your ignorence. WHAT DO YOU WANT, life is not about what you want life is about what is. I have been criticised in life for being a realist. Crap never interested me. If you wish after you have fixed that that you stuffed up, just ask, but dont move those magnets.

HiTech
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Jul 18, 2007, 1:58 PM

Post #10 of 16 (4129 views)
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Re: [EMUGOD] old Sony trinitron [In reply to]	Can't Post

"i really doubt you know where the degauss circuit would be?"
Well one thing's for sure, you certainly don't know where it is or how to diagnose it! I used to service video games for a mall arcade store and kids would take magnets to the CRTs weekly. Just think of the downtime and loss of income for that place, if I had messed with purity magnets everytime there was a color blotch here and there!

EMUGOD
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Jul 18, 2007, 2:03 PM

Post #11 of 16 (4127 views)
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Re: [HiTech] old Sony trinitron [In reply to]	Can't Post

so, instead of trying to help me, you tell me that i don't know where it is. thank you for that.

nobody has actually given me any advice here, they've simply shut down all my plans for fixing this thing. calm down about the magnets, they can easily be readjusted back to their original position.

what i am trying to do now is locate the degauss circuit, but instead everyone here seems content to wave around their e-penis and tell me what a moron i am for moving the magnets.

HiTech
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Jul 18, 2007, 2:32 PM

Post #12 of 16 (4124 views)
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Re: [EMUGOD] old Sony trinitron [In reply to]	Can't Post

e-penis? LMAO!
#1 Have you looked inside the cabinet for any other identification labels? Sony has on older models done that.
#2 If you Google Images for old Sony TVs you may get lucky and see your set, duly noting the model #
#3 The degauss circuit likely can be traced by locating the electrically taped coil (sometimes inside vinyl tubing) that's held around the picture tube's perimeter. From that coil there will be two wires that lead back to the circuit board and likely attaches to it via a plug (a two conductor, small rectangular, white connector plugged into the board). From there the degaussing circuit's associated components should be in the general vicinity. But even then you are at a standstill without further troubleshooting skills. Obviously you can look for burned or charred components or bad foil traces. Check the underside of the circuit board for poor to bad solder connections.... very common and an easy quick fix. Without a model # and a diagram to go on, further diagnosis on this end is not easy. You can always put your credit card right next to the degaussing coil as you power up the set. Then go try and purchase somethign with it. If it's rejected, your degaussing circuit is working! Call the card company and request a new card!!! Wink

There, now is that what you needed?

(This post was edited by HiTech on Jul 18, 2007, 2:36 PM)

EMUGOD
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Jul 18, 2007, 2:45 PM

Post #13 of 16 (4121 views)
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Re: [HiTech] old Sony trinitron [In reply to]	Can't Post

#1 yea, no such luck. there is only the servicemans label and a safety warning label, neither of which has mentions of a degauss circuit (which was the first thing i checked after being pointed in that direction).

#2 the model number is long gone, or else i'd be asking Sony for advice.

#3 thanks, gonna check that now...

HiTech
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Jul 18, 2007, 3:24 PM

Post #14 of 16 (4119 views)
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Re: [EMUGOD] old Sony trinitron [In reply to]	Can't Post

Like I mentioned, try Googling it under IMAGES by inputting words like 1980's Sony Televisions, Old Sony televisions, old trinitrons etc. I have had some luck that way in ID'ing poorly labeled items. I just did that and quite a few photos popped up. Is there a ID label for the CRT itself attached to it? That can also be of help, and thru some research you can narrow it down to a group of models that employed it. BTW, is the cabinet a genuine wood cabinet? I use to have some service literature for those old buggers... might still, or I may have tossed them aside.
Have you looked at both sides of the circuit board for labeling of "sections" or stages of the set? At times they will draw lines of delineation between stages on the PCB. The degaussing circuit is typically located within the power supply circuitry, near the rectification/filtering area. Get a voltmeter across those two connector pins that lead to the degaussing coil. See what kind of, if any voltage exists upon powering up the set from a cold start.

(This post was edited by HiTech on Jul 18, 2007, 3:30 PM)

rrobor
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Jul 19, 2007, 8:11 AM

Post #15 of 16 (4104 views)
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Re: [EMUGOD] old Sony trinitron [In reply to]	Can't Post

Point 1/ how do you switch the TV off,
Point 2/ exactly how much do you know about TV repair
Now I can help you here, I suspect you have a remote and switch off with that. Point 2/ When your TV went faulty you did a bit of research, perhaps an hour or so and came to the concusions you did. Now if this is correct we can deal with this. You state I am trying to measure my penis, I can tell you now its too long. I get a camera shoved up it every 6 months. That is not my pleasure in life. When you have seen the inside of your penis as I have, I will grant you that gibe, till then shut up and take the advice you are given, or go on your merry ignorant way. Your degauss circuit is a set of coils around the bell of the tube, it comes to a plug on the board. Near by is a square plastic box about 1cm sq Sony's usually are black, that is it.

HiTech
User

Jul 19, 2007, 1:49 PM

Post #16 of 16 (4100 views)
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Re: [EMUGOD] old Sony trinitron [In reply to]	Can't Post

Some of those 80's vintage Sonys had a push/pull switch mounted to the volume pot.... no remote ctl.!

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