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gregstv
Joined: 27 Aug 2007
Posts: 628
Location: Australia
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| Posted: Wed Jan 09, 2008 2:22 am Post subject: nec pg |
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Hi all
I had a fault with my pg 9 where the picture was going light and dark.The fault was caused by leaky
capacitors on the gain control board.It might be a good idea if you have a pg to check these caps
as some were leaking that bad it was eating the copper tracks. change all the 4.7uf ,47uf and the 100uf
capacitors.I also found the same problem with the caps on the video output board around the vph06
chips.
Just sharing what i found.
Thanks
Greg
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Tinman
Joined: 09 Mar 2006
Posts: 1326
Location: Carson City Nevada
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| Posted: Wed Jan 09, 2008 2:39 am Post subject: |
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This is becomming common now. Also the caps on the wave board and several on the Deflection board.
Marc
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deronmoped
Joined: 03 Nov 2006
Posts: 1154
Location: San Diego
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| Posted: Wed Jan 09, 2008 5:47 am Post subject: |
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I'm thinking that caps should last for a long long time, if quality control was perfect.
Some caps last forever, while others can go at any time.
Deron.
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gregstv
Joined: 27 Aug 2007
Posts: 628
Location: Australia
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| Posted: Wed Jan 09, 2008 6:39 am Post subject: |
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NEC are the king of crap capacitors.There tvs and vcr from around the same year are just as bad
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Tinman
Joined: 09 Mar 2006
Posts: 1326
Location: Carson City Nevada
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| Posted: Wed Jan 09, 2008 8:32 pm Post subject: |
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| gregstv wrote: | | NEC are the king of crap capacitors.There tvs and vcr from around the same year are just as bad |
Excuse me??? I am replacing capacitors by the bucketloads on most 20+ year old gear.
Crap capacitors can be found in modern stuff. Those little silver surface mount horrors. 1000 hour lifespan.
You have to agree that the old stuff was much better. Caps only last so long, no matter what they are in.
NEC used pretty decent components. Try having a PG made in China NOW and see how long it runs.
Marc
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gregstv
Joined: 27 Aug 2007
Posts: 628
Location: Australia
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| Posted: Wed Jan 09, 2008 9:55 pm Post subject: |
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We were changing caps in nec tvs and vcrs when thay were under 12 months old in the early 90s
We did not have the same capleakage at that time in any other brand.My pg only has 3500 hours on it and the caps are leaky.
I have a sony1251 thats been around the clock and no copper being eaten there.NEC used caps that leaked acid and stunk.
As for the new surface mount caps we see a few problems but not like the old days.Maybe thats because a lot
of people replace there items and not get them repaired.
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Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
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| Posted: Wed Jan 09, 2008 9:59 pm Post subject: |
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Frankly I disagree. I have the odd cap go in NECs, but no more than in Barcos or other sets.
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gregstv
Joined: 27 Aug 2007
Posts: 628
Location: Australia
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| Posted: Wed Jan 09, 2008 10:23 pm Post subject: |
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Maybe its a climate thing
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Tinman
Joined: 09 Mar 2006
Posts: 1326
Location: Carson City Nevada
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| Posted: Wed Jan 09, 2008 10:30 pm Post subject: |
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| gregstv wrote: | | Maybe its a climate thing |
That's possible. I have seen equipment with thousands of hours with good caps, and stuff with only a few hundred but bad caps.
Also, there have just been bad runs. Just look at some of the motherboard cap problems.
And then there's heat.
Marc
BTW, Greg, did you check the 10uF 160volt caps on the video out board?
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Last edited by Tinman on Wed Jan 09, 2008 10:34 pm; edited 1 time in total
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Tinman
Joined: 09 Mar 2006
Posts: 1326
Location: Carson City Nevada
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| Posted: Wed Jan 09, 2008 10:31 pm Post subject: |
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| Curt Palme wrote: | | Frankly I disagree. I have the odd cap go in NECs, but no more than in Barcos or other sets. |
Have you had any even caps go yet? 
Marc
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gregstv
Joined: 27 Aug 2007
Posts: 628
Location: Australia
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| Posted: Wed Jan 09, 2008 10:43 pm Post subject: |
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Hay Marc what problems are caused by the caps on the wave board.
I was playing with different res on the pg and a bluray player.the pg locked up on the picture at 1080p
but the on screen display had no sync.Not that i would run 1080p but this could be a fault starting in the making.
Not sure if the player was putting out 1080p/60 or 1080p/24fps.
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Tinman
Joined: 09 Mar 2006
Posts: 1326
Location: Carson City Nevada
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| Posted: Wed Jan 09, 2008 10:59 pm Post subject: |
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Bad wave board caps cause instability and convergence drift. I have also seen domed caps on the C and F drives, although not common. Heat related, I think. Sync issues are often caused by the little caps around the oscillator IC on the deflection board. That could also cause scrambled menus.
Marc
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gregstv
Joined: 27 Aug 2007
Posts: 628
Location: Australia
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| Posted: Thu Jan 10, 2008 12:03 am Post subject: |
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I have changed all the caps on the deflection board and in the power supply.
Time to get the circuit out and find out where the menu sync is generated.
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Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
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| Posted: Thu Jan 10, 2008 12:38 am Post subject: |
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| Tinman wrote: | | Curt Palme wrote: | | Frankly I disagree. I have the odd cap go in NECs, but no more than in Barcos or other sets. |
Have you had any even caps go yet?
Marc |
Oh yes, I've got the standard ones I check, but like I said, I think I change more caps in Barcos. Mind you, those sets are older. I know NECs each chips for breakfast, but not caps.
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Tinman
Joined: 09 Mar 2006
Posts: 1326
Location: Carson City Nevada
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| Posted: Thu Jan 10, 2008 12:55 am Post subject: |
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Curt, I find that Barcos and caps do not go well together. And I'm talking broadcast video monitors. I don't know what the deal is, but I won't work on them any more.
BTW, any news on the AKAI? Mine is running great now. There is a small dent in the plaster next to my door, however. About forehead height.
Marc
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