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  #1  
Old 11-21-2007, 11:52 PM
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YamahaFreak YamahaFreak is offline
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Advice on (hopefully) simple repair to RCA HDTV

Yep, I've done it again! Second curbside TV in a month. This one is a 2004 RCA (Thompson) 52" HD rear projector. The guy said it quit working about a week ago. I get it home(inquire about sidesplitting story!)and plug it in. The standby LED lights up and the power supply energizes, but the set doesn't turn on. I remove the back panel and find a thoroughly toasted resistor on the back of the mainboard, well away from the PSU. The carnage on the board roasted off most of the part #, but judging by the others on the board, I think it is number R14703. The rest of the board is clean. Pics:

http://img210.imageshack.us/img210/5631/1020790nr3.jpg

http://img411.imageshack.us/img411/1545/1020791du9.jpg

http://img211.imageshack.us/img211/7751/1020792wj4.jpg

Also, in the first pic, you can see on the screen what looks like shadowy arches; I don't know if this is a burn or other damage to the screen, or just a reflection. It's only noticeable from some angles under certain lighting. Hoping to get this working to go in our pool room for Super Bowl and gaming.
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  #2  
Old 11-22-2007, 12:27 AM
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Have you got a model or chassis number. Should be on a piece of paper located on the rear cover. I'm not familiar with RCA's newer bigscreens; but, their direct view sets of this era are known for having bad flyback's. You'll probably have to obtain service information on this set to determine what value the resistor is. Then, you'll have to find out what drew too much current and burned the resistor. You may try tracing the foil on the underside of the board to see what the resistor connects to. You may possibly have some type of solid state device (IC, transistor, diode, etc.) that has shorted. And, it could have very well have been the flyback that went bad. Like I said, they are high failure parts in the direct view sets.
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  #3  
Old 11-22-2007, 12:36 AM
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The model number is HD52W56, chassis #ATC321. There is no mention of DirectView anywhere on the set. Where would I obtain said service info?
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Old 11-22-2007, 12:55 AM
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That's a carbon composition resistor, so it's probably a very high value resistor (1M or 10M). The only places they often still use these are for things like coupling the line to the chassis.
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  #5  
Old 11-22-2007, 01:01 AM
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Quote:
Originally Posted by andy View Post
That's a carbon composition resistor, so it's probably a very high value resistor (1M or 10M). The only places they often still use these are for things like coupling the line to the chassis.
Meaning? (sorry, ) Also, like with the last set I was working on, could I replace this resistor without touching anything else? I will remove the board and look at the traces when I get back from Thanksgiving vacation on Saturday.
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Old 11-22-2007, 01:23 AM
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I looked on the internet and found that he HV splitter is a very common problem on these sets and can burn some resistors with it. R14705, R14718, & R14719 are said to be the resistor location numbers of the ones that smoke. The HV splitter part number is 258512.
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  #7  
Old 11-22-2007, 01:39 AM
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Quote:
Originally Posted by radiotvnut View Post
I looked on the internet and found that he HV splitter is a very common problem on these sets and can burn some resistors with it. R14705, R14718, & R14719 are said to be the resistor location numbers of the ones that smoke. The HV splitter part number is 258512.
I scraped off some of the burn with my fingernail and the blown resistor is indeed R14705. Still new at this; what is a HV (assuming stands for High Voltage) splitter and what does it look like? Also, where on the chassis is it usually located, and are they expensive/hard to replace? Sorry for all the questions.

EDIT: I just perused the PS and mainboard for ten minutes and couldn't find anything with #258512 on it.
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  #8  
Old 11-22-2007, 10:03 AM
Bill R Bill R is offline
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The splitter is usually located off the main board. It is a small box with 4 or 5 large wires connected to it. It splits the high voltage from the flyback to each of te 3 projection tubes. They are not usually to hard to replace.

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  #9  
Old 11-22-2007, 11:06 AM
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That RCA part number is usually never on the parts. The only way you can get the RCA part number is to either have the service information or some type of parts cross reference for the set. I just happened to find the part number on the internet. If you replace the splitter, try to stick with an original RCA. It's been my experience that the cheaper generic ones don't hold up that long.
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  #10  
Old 11-22-2007, 01:10 PM
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Quote:
Originally Posted by YamahaFreak View Post
Yep, I've done it again! Second curbside TV in a month. This one is a 2004 RCA (Thompson) 52" HD rear projector. The guy said it quit working about a week ago. I get it home(inquire about sidesplitting story!)and plug it in. The standby LED lights up and the power supply energizes, but the set doesn't turn on. I remove the back panel and find a thoroughly toasted resistor on the back of the mainboard, well away from the PSU. The carnage on the board roasted off most of the part #, but judging by the others on the board, I think it is number R14703. The rest of the board is clean. Pics:

http://img210.imageshack.us/img210/5631/1020790nr3.jpg

http://img411.imageshack.us/img411/1545/1020791du9.jpg

http://img211.imageshack.us/img211/7751/1020792wj4.jpg

Also, in the first pic, you can see on the screen what looks like shadowy arches; I don't know if this is a burn or other damage to the screen, or just a reflection. It's only noticeable from some angles under certain lighting. Hoping to get this working to go in our pool room for Super Bowl and gaming.
Dang, that looks like the same set my buddy just bought at Wal*Mart this week (his F-150 is down so I helped him take it home in my Ford "Exploder") so that's why I'm keeping my eye on this thread to see if there is any more issues.
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  #11  
Old 11-22-2007, 01:53 PM
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you will have to replace the splitter or watch those parts go up in smoke again. those are great playing sets. about $50.00 bucks in parts and you have a fine tv. steve
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  #12  
Old 11-22-2007, 02:01 PM
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ok here are your part numbers. splitter 258512 r14705 238958 which i believe is a 27k ohm 1/4watt carbon r14718 260880 r14719 175046 tritronics has the splitter and resistor in stock. that is where we buy all our rca parts. they are original not generic.
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  #13  
Old 11-24-2007, 03:41 PM
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Thanks for the help, guys! I'll get on this repair ASAP. Does anyone have a link to the Tritronics site? I Googled it and all I see is dog training sites?
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  #14  
Old 11-24-2007, 03:44 PM
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www.tritronicsinc.com
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  #15  
Old 11-25-2007, 03:55 AM
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I did some more snooping and found this component behind the front access panel beneath the speaker grille. Would this be the HV Divider?

http://img402.imageshack.us/img402/7...dividerun0.jpg

Looks kinda like a mutated flyback, with each of the three leads going to one of the three RGB CRTs. The fourth lead is coming from the main flyback, I assume? Also, when replacing, do I disconnect the leads at the tubes or the divider?
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