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Marcel_D
Joined: 22 Sep 2007
Posts: 54
Location: Canada
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| Posted: Thu Jul 18, 2013 12:21 am Post subject: NEC 9PG+ Corrupt Menus and no Video |
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My PG 9+ has been sitting for some time and I decided to recalibrate it today. It was on for about an hour in which time I recentered the rasters and adjusted the input signal's front and back porch settings.
At one point I decided to adjust the keystone to make the raster a bit more square and as I moved it below the midpoint setting I could hear a hum from the projector getting louder as I changed the setting, but as I adjusted in the opposite direction it went away. Just as I was doing this I lost the video display from the tubes and it gave me an "Unregistered Signal" error.
Now the tubes won't display video and when I try to bring up a test pattern you can hear the relays clicking and displaying some noise but no test pattern shows up.
I have a bit of electronics experience. Before ripping into it I wanted to see if this was a known issue or perhaps a board that needs replacing.
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the big E
Joined: 20 Apr 2013
Posts: 1928
Location: speedwell Tn.
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| Posted: Thu Jul 18, 2013 12:38 am Post subject: |
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Could be the caps on the boards
I know how you feel my 10pg is needing some caps replaced due to age as mine only have video on the red and blue tubes
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crt king of black
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CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
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| Posted: Thu Jul 18, 2013 3:36 am Post subject: |
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Pull the boards out and re-seat them and see if it goes away. The buzzing is probably the 47uF capacitor at the front of the DEF board. If you change it, use a 470uF that can handle a high ripple current.
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Marcel_D
Joined: 22 Sep 2007
Posts: 54
Location: Canada
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| Posted: Thu Jul 18, 2013 3:54 am Post subject: |
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| CasetheCorvetteman wrote: | | Pull the boards out and re-seat them and see if it goes away. The buzzing is probably the 47uF capacitor at the front of the DEF board. If you change it, use a 470uF that can handle a high ripple current. |
So they're using an underrated filter cap there?
I'll pull the boards and see how it goes.
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Tinman
Joined: 09 Mar 2006
Posts: 1326
Location: Carson City Nevada
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| Posted: Thu Jul 18, 2013 4:01 am Post subject: |
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| Marcel_D wrote: | | CasetheCorvetteman wrote: | | Pull the boards out and re-seat them and see if it goes away. The buzzing is probably the 47uF capacitor at the front of the DEF board. If you change it, use a 470uF that can handle a high ripple current. |
So they're using an underrated filter cap there?
I'll pull the boards and see how it goes. |
Not really..... I have had pg's with 10uF caps in that spot that never buzzed. But we know that a bigger cap just makes up for the failing one that's in the power supply.
These sets need caps now, no way around it.
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This space for rent.
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CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
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| Posted: Thu Jul 18, 2013 4:46 am Post subject: |
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No the cap they used is quite large, not underated.
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Marcel_D
Joined: 22 Sep 2007
Posts: 54
Location: Canada
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| Posted: Thu Jul 18, 2013 5:09 am Post subject: |
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Reseated the boards to no avail. Checks the caps on them and some of them have a higher than normal ESR which isn't a big surprise. I have the deflection board sitting in front of me and I think the 47uF cap has been changed. It's now a 47uF Rubycon with a very low ESR reading. A few others in the area are also Rubycons. I did purchase this set from Curt back in 07.
I think I'll start probing test points and looking at waveforms soon. Hope and pray that I can narrow it down...
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CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
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| Posted: Thu Jul 18, 2013 6:07 am Post subject: |
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The 47uF Rubycon is OEM, it wont need replacement i dont reckon, pull it off an see if its leaking.
The others will be a mix of Rubycon and Nichicon, and both leak due to nothing more than age. They leak even on an unused zero hour set.
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Marcel_D
Joined: 22 Sep 2007
Posts: 54
Location: Canada
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| Posted: Thu Jul 18, 2013 7:55 am Post subject: |
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| CasetheCorvetteman wrote: | The 47uF Rubycon is OEM, it wont need replacement i dont reckon, pull it off an see if its leaking.
The others will be a mix of Rubycon and Nichicon, and both leak due to nothing more than age. They leak even on an unused zero hour set. |
Well...I don't have a leakage tester. Or a 200V DC power supply to even do a basic test of it. I could just replace it for the heck of it. Considering you've recommended a capacitor with 10x the capacitance rating it seems like a wise decision.
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CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
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| Posted: Thu Jul 18, 2013 8:06 am Post subject: |
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No i recomended 470uF. By leaking i mean losing its electrolyte.
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Marcel_D
Joined: 22 Sep 2007
Posts: 54
Location: Canada
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| Posted: Thu Jul 18, 2013 8:13 am Post subject: |
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| CasetheCorvetteman wrote: | | No i recomended 470uF. By leaking i mean losing its electrolyte. |
Ooh well then, no electrolyte here.
Well...next move. The unit shows no error codes. I can't believe the troubleshooting guide for these things is in the archaic NEC software. I tried to get it working in DOS Box but after you put in the passcode it just kicks you out to the command prompt.
I think I'm too tired to look start troubleshooting today. I'll just think about it for a while.
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CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
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| Posted: Thu Jul 18, 2013 8:42 am Post subject: |
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Dont bother with that, just get to replacing capacitors, itll quite likely work fine after you do.
You quite often cant see these caps leaking til you remove them.
Dont desolder the legs to remove them, cut the legs and solder the new capacitor to the legs. The larger ones can be desoldered.
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Marcel_D
Joined: 22 Sep 2007
Posts: 54
Location: Canada
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| Posted: Thu Jul 18, 2013 8:44 am Post subject: |
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| CasetheCorvetteman wrote: | Dont bother with that, just get to replacing capacitors, itll quite likely work fine after you do.
You quite often cant see these caps leaking til you remove them.
Dont desolder the legs to remove them, cut the legs and solder the new capacitor to the legs. The larger ones can be desoldered. |
Sounds like a plan. Any critical areas to start with? DEF board seems like a good one...or even the power supply.
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CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
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| Posted: Thu Jul 18, 2013 8:53 am Post subject: |
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Start with the DEF board, then do the WAVE, POINT, and SYSTEM boards. That should get it up and running, the video output board should also be done, i also got alot of leakers off the GAIN CTL board.
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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 Jul 18, 2013 1:02 pm Post subject: |
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Marcel, just an FYI, I've stopped repaiting PG sets due to leaking capacitors taking out multiple boards. Be prepared to change 100+ caps on as many boards as you can pull. Deflection and system board is a godo start. I suggest leaving off the cover to the system board cage as well since it blocks a bunch of heat movement.
To me it's not worth $50+ in parts and 4-5 hours time at this point, but have at it. you'll find many caps that have leaked electrolyte under them, and in some cases it runs down the board, eating PC board foil along the way. Clean that all up with isopropyl alcohol and a toothbrush.
Get a capacitor ESR meter, it's the fastest way to find the bad caps. they're $75-200 on eBay.
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Thu Jul 18, 2013 3:11 pm Post subject: |
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Curt. Are we now giving online support for NECs? Since your not repairing them anymore.
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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 Jul 18, 2013 4:41 pm Post subject: |
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I still have a boatload of parts to sell off that do work. I wouldn't go right down to component level diagnosis, but telling someone that they need to change 100+ caps will give them an idea whether it's worth it or not. 
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Thu Jul 18, 2013 5:01 pm Post subject: |
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Ok. You got it..... 
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Thu Jul 18, 2013 5:05 pm Post subject: |
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Hmmm. I just reread my post and that was not what I meant to say. What I meant was:
"Are you now allowing online support for NECs? Since your not repairing them anymore.
"
I won't comment on repairs as I have said before unless you approve it.
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Marcel_D
Joined: 22 Sep 2007
Posts: 54
Location: Canada
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| Posted: Thu Jul 18, 2013 8:42 pm Post subject: |
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Thanks for the info Curt. I realize it's a pretty big job and I've debating whether or not it for a while now. I also do have an ESR meter which should speed things up if I choose to.
Like, the PG 9 is an alright set, nothing top tier. If I had paid $3k+ for it I'd be a lot more willing to just jump into this. At the moment I'm not sure.
So my options:
-Put a fair bit of money and time into an average projector (the 9PG)
-Buy a more recent, higher end CRT projector and be nmore willing to invest in it when things go wrong
-Go digital
Maybe I'll just start measuring and making a list of caps. Price it out on Digikey and see if it's worth it.
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