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  #1  
Old 05-12-2013, 05:07 PM
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josephdaniel josephdaniel is offline
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Should I start on my predicta?

A recent thread on here got me thinking about my Predicta and weather or not to pull the PCB and go ahead with recapping it and replacing the out of tolorence resistors.
Currently I have no tube tester and I don't know how to test the CRT since it has the original CRT and my CRT tester puts out 6 volts. Someone in the not so distant past replaced the electrolytic capacitors but didn't touch the PCB.
Whenever I power up the set I get a dim angry line across the center of the screen but with the video line connected I get a cockeyed raster

Should I go ahead and pull the PCB and replace all of the out of tolorence resistors and capacitors on the board with the risk that the picture tube may be bad? I would hate to do all of that work and have a dud set since I know how hard it is to find a replacement jug for these
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Old 05-12-2013, 05:45 PM
jmetal88 jmetal88 is offline
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I risked it with my Zenith, and was pleasantly surprised when the CRT came on after all the re-capping. I guess it depends on how much you have to spend on capacitors, though. I think my order was only around $30 or so, so it was worth it to find out if tube would work, to me.
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Old 05-12-2013, 05:48 PM
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Well, it couldn't hurt anything either. I'd go ahead and fix it up. The CRT sounds like it's good enough to produce a picture. The dimness could be the chassis' fault too. At least if the tube is bad, that would be the only thing left to fix instead of the whole thing needing work.
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Old 05-12-2013, 06:03 PM
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Will A Sencore cr 161 test the origional 2V tube? I am mostly just looking for a excuse to get this one thats been for sale for 30.00 dollars for a few weeks now
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File Type: jpg s2.jpg (33.8 KB, 21 views)
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Last edited by josephdaniel; 05-12-2013 at 06:09 PM.
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Old 05-12-2013, 10:28 PM
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Yes it will do 2V CRT's
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Old 05-13-2013, 09:18 PM
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Quote:
Originally Posted by josephdaniel View Post
Will A Sencore cr 161 test the origional 2V tube? I am mostly just looking for a excuse to get this one thats been for sale for 30.00 dollars for a few weeks now
I like my 161 and it did good on the clean function with my Predicta. When on "clean" the filament voltage stays the same so that's a safe thing for that tube!
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Old 05-13-2013, 10:56 PM
6GH8cowboy 6GH8cowboy is offline
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Dim picture?

Just food for thought. Before getting all wraped up about testing the crt it might be worth removing the front cover and cleaning the crt. This one I worked on had a fairly bright line before the vertical got fixed and a weak but useable raster afterwards. After the rest of the resto, I removed the front to get the HV connected to the crt I discovered the face of the tube was BLACK WITH DIRT? SMOKE? WHATEVER. After cleaning the picture looks like new crt. Might be worth a look see.
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Old 05-13-2013, 11:10 PM
6GH8cowboy 6GH8cowboy is offline
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Predicta PCB removal

I found on this princess that the pcb could be carefully tilted up by
  1. unsoldering the Linierity control wire
  2. removing the width control carefully leaving the wires intact
  3. unbolting the crt connector flange fron the chassis
  4. unbolting the noise limit pot bracket
  5. unsoldering the chassis ground tabs
  6. bending a couple chassis tangs holding the board down
At this point the pcb can be tilted up from the rear because most of the wiring runs to the front of the chassis
There will be wires to be moved out of the way at the sides and its good to take out the larger taller tubes.

Now you can replace the caps, check and replace resistors and solder the pins on all tube sockets.

Clean and carefull replacement of components will pay dividends later.
Good luck. Go for it.
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  #9  
Old 05-13-2013, 11:21 PM
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Quote:
Originally Posted by 6GH8cowboy View Post
Just food for thought. Before getting all wraped up about testing the crt it might be worth removing the front cover and cleaning the crt. This one I worked on had a fairly bright line before the vertical got fixed and a weak but useable raster afterwards. After the rest of the resto, I removed the front to get the HV connected to the crt I discovered the face of the tube was BLACK WITH DIRT? SMOKE? WHATEVER. After cleaning the picture looks like new crt. Might be worth a look see.
I already tried this but I think its lucky that I get anything on the screen at all considering that there are still paper caps on the board.

I was going to do that but the wire used here is solid core so I fear that it may break if I flex it too much. and if I remove the whole board it gives me a chance to check everything very thoroughly.
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Old 05-14-2013, 12:09 AM
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Most wires in TVs are fairly sturdy.
As for the non-coaxial wires running to and from the chassis unless you snap them mid way through their length it should not be a problem if they break as there is usually a bit of slack and lead lengths are not too critical within reason. And even if you ruined a wire, SO WHAT, it is not like you can't get something that will work as a replacement(the shack, electronic supply houses, the internet, junk sets, etc. all stock usable wire).
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