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Sony KV-35V45, Bad CRT. Looking for short...

 
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cheebster
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PostPosted: Sat Aug 04, 2007 6:24 pm    Post subject: Sony KV-35V45, Bad CRT. Looking for short... Reply with quote

Hi. I tought i would start a new topic, since i've focused my problem and my questions are different now. I have this 35 inch tv with a bad crt.

First tv was intermittent. Green background instead of black, and pink instead of whites. Tapping on the crt got it back to life, i have a short there. It went ok, and then again bad and it's even worst.

Here's my question now; i'm checking to find the short on the CRT. And, possibly blow it off.

Which pins of the CRT should have continuity ? I'm trying to understand but i'm having a hard time. I see pins labeled as :

1 - EC
4 - E-SPG
5 - G2
6 - G1
7 - H1
8 - H2
9 - G1-2
10 - KB
11 - KG
12 - KR
13 - G1-3

I see that CV, E-SPG, G1, H1, G1-2 and G1-3 are all connected together on the pc board connected on the CRT.

On the CRT tube pins, i see continuity between G1-2, G1-3 and G2. Is this normal ?

I also see continuity between G1 and H1, and G2 and H2.

I'm trying to understand how this thing works here, i don't know how it works at all. H1 and H2 are the heater, on which i can pump 10V to clear it out ? I don't understand where my short is, how to find out and how to clear it.

If anyone got light me up on this case i would really appreciate it. I understand that buying a new tv is the best choice, but environmentally wise i don't think it is. I don't wanna trash this TV whatever time it takes me.

Thanks in advance, Vincent.
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PostPosted: Sat Aug 04, 2007 6:41 pm    Post subject: Reply with quote

Ok. I forgot to add something. I've measured the KR KB and KG on the pcb on the CRT. If the board is off the CRT tube, voltages are all 209V.

When on the CRT tube, i get 209V on both R and B but green fluctuates from 109 to 209V. Would that say something about what is shorted with what ?

I can't see any shorts on the meter from KG to H1 or H2.

Thanks !!! Vincent.♦
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minnie



Joined: 18 Aug 2005
Posts: 2877
Location: Hell

PostPosted: Sat Aug 04, 2007 6:47 pm    Post subject: Reply with quote

Welcome to the world of Sony. Your tube is junk. Best you could do is see if anyone has a tube they'd be willing to give up.
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cheebster
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PostPosted: Sat Aug 04, 2007 6:59 pm    Post subject: Reply with quote

Minnie, why junk ? That doesn't help me much. I'd like to be able to at least, understand where's the short and try to clear it.♦
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minnie



Joined: 18 Aug 2005
Posts: 2877
Location: Hell

PostPosted: Sat Aug 04, 2007 8:48 pm    Post subject: Reply with quote

Inside the picture tube are 3 guns. Red, green, and blue. Your short is internal. You would have to regun the tube to eliminate the short. A replacement picture tube is NLA and the price to regun the tube would out way the repair. That was a $1600 set new. Sony is notorious for bad picture tubes. It's not "junk" if your willing to watch the picture in it's present condition. You could try and rejuvenate the tube.

http://cgi.ebay.com/BK-Precision-470-Cathode-Picture-Tube-Tester-w-CR-12_W0QQitemZ280139971043QQcmdZViewItem

Sony does not bond the yolk. If you would put a different CRT in, setting the geometry would be a nightmare. One out of 10 goes good and give the customer an 'acceptable' picture.

http://answers.yahoo.com/question/index?qid=20060901174046AA2sDz3
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cheebster
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PostPosted: Sat Aug 04, 2007 11:04 pm    Post subject: Reply with quote

Hi there. Well, ok. I have B&K model 445, and a model 467. There is an adapter that i would need to use the 467 for the sony. It's the CR-23, which isn't available anymore, it's been replaced by the CR-XA adapter, which is 75$USD + shipping.

Wondering if it worths it to buy the adapter or not. I've been trying to find the pinouts for the 445 model and just hardwire it with small connectors on the CRT, but B&K didn't have the information, and it didn't seem available on the internet Neutral

Thanks.. Vincent
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PostPosted: Wed Aug 22, 2007 5:26 pm    Post subject: Reply with quote

Hi. I'm still having problems with that damn tv !!! Ok, i've got a working socket adapter for this tv, and i've tried to rejuvenate it, it didn't do the trick.

The tv went ok for a few minutes, picture was black crisp and nice, and a nice spark occured again in the CRT tube. Back to square one, tv is green and flashing on off. I got a short between KR and Heater.

I've tried zapping the short away with a 47UF 200V capacitor. Didn't do the trick either. Anyone got an idea of something i could try ? Thanks, Vincent.
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PostPosted: Wed Aug 22, 2007 6:48 pm    Post subject: Reply with quote

I meant, KG and heater short. Sorry.
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PostPosted: Fri Aug 24, 2007 4:28 pm    Post subject: Reply with quote

A rebiult tube is realy your old tube with a neck replacement and if you are lucky there is rare earth replacement. long time ago people were into the business not any more too expensive and EPA go after them with fines. dirty mess. when you hit the tube you have cleared the temporary short that is an old trick. better way is to blow it clear with some source of current but you have to know where. good luck
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