Zenith prjection tv, sound good, no picture.


  #1  
Old 06-28-02, 09:05 PM
mrklipp
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Zenith prjection tv, sound good, no picture.

This is a Zenith Digital System 3 projection tv. It had been sitting unused for some time, I turned it on, heard whine, no picture. Had to do something else, forgot and left it on. When I came back several hours later it was on and looking fine. Well, after shutting it back off and moving it to another room, it now has gone back to how it was, whine, sound, but no picture. I tried leaving it on for a day, that isn't working this time. The fuses look good, any sugestions of what to check?

Thanks in advance.
 
  #2  
Old 06-29-02, 12:16 AM
FREDDYG_001
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mrklipp, That whine you heard was the switch-mode transformer in the power supply. What you need to do is remove the bottom back cover, look on the inside of that cover for a circuit board layout diagram. Find the sweep/power supply module on that diagram and write down the part number. If you can't find it their look for the part number on a little white label on one of the metal heatsinks on the sweep/power supply module. Also need the model number and date of manufacture of this television. This imformation is on the back cover.

Zenith module part numbers start with 9-xxxxx, four numbers after the dash the a letter.


Post back with this imformation.


Fred
 
  #3  
Old 06-29-02, 01:15 AM
mrklipp
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sweep is part # 9-629
switch mode power supply is part # 9-628

Model is pv4661h

Manufactured Feb 89

Thanks. =)
 
  #4  
Old 06-29-02, 12:05 PM
FREDDYG_001
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mrklipp, (1). Before we say replace the modules pulled both modules and check for any cracked or burnt solder joints, if you find any take your solderwick and soldering iron and remove the old solder any replace it with new solder. If you can get your hands on a capacitor checker/tester meter (hand held one) check those capacitors on the power supply board, take a screwdriver short across the legs of the capacitor before you connect your meter.


(2). It depends on how much this television is worth to you. Keep in mind this television is 12 years old. If you find nothing after doing your checks and you decide to replace the module(s), here are the prices. You'll need to look on each module for the full part number.


www.ptscorp.com
9-629-09 dealer net $80.95 dealer op $90.95 dud $28.00
They did not have the 9-628 module but, they do rebuild modules.

www.partsearch.com
9-628-04R $176.80
9-628-07 $173.40
9-628-09R $360.40
9-629-02R $207.40


Fred
 
  #5  
Old 06-29-02, 06:59 PM
mrklipp
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I appreciate the response, just what I was looking for. I didn't really know what to look at first. I'll pull those first and see what I can find. I figure if it is something I can repair without replacing the whole module, it's worth the time. The tv was sitting in a garage for 6 or so of those 12 years, so I figure I might get lucky and get some use out of it yet. One more quick question, should I also check out any of the other power supply modules? I'll give those two modules a carefull look over and come back if I need some more help. Thanks again.
 
  #6  
Old 06-29-02, 07:41 PM
FREDDYG_001
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mrklipp, Before you do that concentrate on getting the television up and running first, that way you can determine if you have other problems with the other modules by letting that television play.



Fred
 
  #7  
Old 06-29-02, 08:16 PM
mrklipp
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Well, as I mentioned when I first started this It did turn on, and I hooked up a vcr to test it and everything looked great, that's why I want to give this a try. Any further advice for what to check or things to watch out for is appreciated, I don't have much (hardly any) experience with tv repair but I have done a bit of other hopefully related stuff. (Etching and building pcbs for projects, modding dvd players for multi regien, etc.) My plan at the moment is as follows: Remove above mentioned two modules (suggestion of which to do first?) Check for cold soldered joints, check for burned/cracked joints/ traces. Check for continuity on all the traces and connections. Try and get my hands on something to check the caps(any suggestions on where to pick up a tester. how much it would cost? Fry's? Rat shack?) Let me know if I am off base with any of this.

Thanks again
 
  #8  
Old 06-30-02, 01:33 AM
FREDDYG_001
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mrklipp, Whichever way you want to start is up to you.


Mat Electronics offers two meters:
Model ST-9500TF
Digital Multimeter w/capacitance
Cost. $34.95

Model CM-210
Digital Capacitance Meter
Cost. $49.95

www.matelectronics.com
1-800-628-1118


Fred

 
  #9  
Old 07-02-02, 12:34 AM
mrklipp
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I pulled those two modules and both looked clean. I'm planning on getting a capacitance tester and checking that out, but before I do are there any other modules I should also be looking at? Also, many of the connectors feel really "loose". Like they are attached, but still a lot of wiggle if you touch them. Is that normal for these type of connectors or should I look for some way to tighten the connections?

Thanks again.
 
 

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