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JustGreg
Joined: 07 Mar 2006
Posts: 3098
Location: Kenosha, WI
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| Posted: Tue Jul 01, 2008 5:48 pm Post subject: VIM Crashed and Burned - Red is Dead |
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The red channel on my 8500(AC) VIM died. (Sorry, at work and forgot the P/N at home). I ruled out HV, neckboard, and the usual culprits and narrowed it down to the VIM. The red tube performs as designed when fed a signal from the G&B mini RCA's. I switched the red coax with blue and it didn't light but it did when feeding it a blue signal so it 'taint the mini coax.
I didn't see anything toasted and there wasn't any lead up to this. I hadn't used the pj for a little over a week and blew off mowing the lawn last night to play some GTA IV and when I powered up the pj, everything came up but the red. No magic smoke, and no booms or bangs.
I don't have a spare VIM any more so I'm down for the count. (And I was just getting around in the game to getting Niko laid!) Any of you board level hot rodder modders have any idea what component is responsible for giving Niko blue balls? 
Thanks in advance for any assistance (or chuckles).
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Greg
"Is it ignorance or apathy? Hey, I don't know and I don't care!" --Jimmy Buffett
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Tue Jul 01, 2008 6:05 pm Post subject: |
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Just for the heck of it did you try switching the red with the blue/green inputs of the vim just to rule out no red from source or cable?
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JustGreg
Joined: 07 Mar 2006
Posts: 3098
Location: Kenosha, WI
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| Posted: Tue Jul 01, 2008 6:43 pm Post subject: |
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| macgyver655 wrote: | | Just for the heck of it did you try switching the red with the blue/green inputs of the vim just to rule out no red from source or cable? |
That's exactly what I did. I just didn't communicate it well. I'm having one of those days when I speak in hieroglyphics.
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Greg
"Is it ignorance or apathy? Hey, I don't know and I don't care!" --Jimmy Buffett
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Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
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| Posted: Tue Jul 01, 2008 7:09 pm Post subject: |
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Did you try the internal patterns? these come in farther down the line and use different op amps than external video. Then we can narrow it down. This is where extender boards come in handy so you can meter diferent areas of the board, like if power is getting to the RGB op amp in question, if the signal is present on the oputput pin, ect ect ect. I made one extender card and i will take pics and list parn numbers once i get home after 11 pm tonight.
Athanasios
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JustGreg
Joined: 07 Mar 2006
Posts: 3098
Location: Kenosha, WI
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| Posted: Tue Jul 01, 2008 7:39 pm Post subject: |
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| Nashou66 wrote: | Did you try the internal patterns? these come in farther down the line and use different op amps than external video. Then we can narrow it down. This is where extender boards come in handy so you can meter diferent areas of the board, like if power is getting to the RGB op amp in question, if the signal is present on the oputput pin, ect ect ect. I made one extender card and i will take pics and list parn numbers once i get home after 11 pm tonight.
Athanasios |
Thanks for the reply guys (pardon my rudeness Mac). I backed out of sources right to the point of physically disconnecting all cabling. Still nothing from the internal pattern on red. G&B work great and haven't lost convergence or focus. And as I said earlier, I fed the red tube the G&B ouput from the VIM to the red tube and the tube worked in both cases. The mini coax for red works on G&B so in my pea brain, that leaves the 'source' red channel on the VIM.
I have a service manual on pdf somewhere. I'll have to dig it out and see if I can apply anything to the problem. I doubt that very much however. The only diagnostic equipment I own is a digitial VOM and a pair of tired 50 year old bespectacled eyeballs.
I have a set of jewlers loupe's....I'll put the VIM under some serious scrutiny tonight (aka bright light) and look for bad solder joint(s).
By the time I get done with all those joints I may very well have to wear the loupes for glasses. 
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Greg
"Is it ignorance or apathy? Hey, I don't know and I don't care!" --Jimmy Buffett
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Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
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| Posted: Tue Jul 01, 2008 8:21 pm Post subject: |
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Ok so no internal patters either so the internal signals are no even being sent to the tube, Both signals go through the Analog switch SD5401cy. 
What this chip does is switch between internal and external video when it recieves a signal to do so for menu overlay and also for patterns. It turns on and off very fast switching between external and internal durring menu overlays therfore allowing the internal video over external at pre determined places during the scan.
I'm wondering if this chip may be the problem, The pic is from the older style vim and has a resistor added to one of the pins. This came loose once and I lost Video but it wasnt not black it was a lit raster with no internal or external. Maybe this
chip is the culprit? But i have never heard of one going bad, but its just a thought.
Antother thing that could be happening is Spotkil is being sent for that channel, but i need to look at the service manual
a bit more first.
Athanasios
_________________
Don't blame your underwear for your crooked ass~ unknown Greek philosopher
"Republicans believe every day is the Fourth of July, but the Democrats believe every day is April 15." --- President Reagan
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Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
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| Posted: Wed Jul 02, 2008 12:23 am Post subject: |
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I forgot about this trouble shooting guide Tim from EtechVideo posted here, G2 voltage on the VNB and the voltage off the mini rca's i think would be most telling......
| Quote: | Hello
Troubleshooting Marquee Video Problems Without A Scope
One does not always have the luxury of a dual trace scope on the road,
here are a few norms to test for if your Marquee has high voltage and
picture problems, like flashing, or no pix at all, or one color is weak:
Vim Mini Coax Levels, Unplugged From VNB:
With CONT of 40 and BRITE of 40, the tip of the mini coax feed
gives 110mv with internal stairstep, 255mv on white field.
Internal Pattern Sequence is 1) Hatch plus Dots,
2) Dots Only, 3) Stairstep, 4) Full White, 5) Source
G2 Values and Voltage, measured at tip of VNB R76:
G2 of 40 gives +375vdc
45 +415vdc
50 +462vdc
55 +510vdc
60 +555vdc
65 +600vdc
70 +646vdc
Fluke DVM dc limit is 655vdc and goes into alarm mode.
Brightness Control Line to VNBs, P13 Pin 8:
BRITE of 0 gives +2.02vdc
10 +1.59vdc
20 +1.19vdc
30 +0.81vdc
40 +0.37vdc
50 - 0.02vdc
60 -0.44vdc |
Athanasios
_________________
Don't blame your underwear for your crooked ass~ unknown Greek philosopher
"Republicans believe every day is the Fourth of July, but the Democrats believe every day is April 15." --- President Reagan
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JustGreg
Joined: 07 Mar 2006
Posts: 3098
Location: Kenosha, WI
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| Posted: Wed Jul 02, 2008 3:00 am Post subject: |
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Impressive bit of sleuthing there Athanasios! I think Tim's doc is based on readings from an O scope no? If I remember correctly my VOM will do milivolts. I have nothing to lose at this point and everything to gain. Tomorrow night I'll see if I can't reproduce some of those readings. (I've been putting off mowing my lawns for over a week so spent the night doing that and fattening up a couple hundred mosquito's in the process. I'm a 6'4" walking itch right now).
I'll get back to this thread and let you know what I found.
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"Is it ignorance or apathy? Hey, I don't know and I don't care!" --Jimmy Buffett
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AnalogRocks
Forum Moderator
Joined: 08 Mar 2006
Posts: 26706
Location: Toronto, Ontario, Canada
TV/Projector: Sony 1252Q, AMPRO 4000G
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| Posted: Wed Jul 02, 2008 3:29 am Post subject: |
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Funny thing Greg. I just picked up a 27" JVC CRT on the curb. ONLY the red worked. lol. Good luck with the testing.
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Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
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| Posted: Wed Jul 02, 2008 3:30 am Post subject: |
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That guide is for use with no scope just a multi meter(volt meter). TSE was also helping me out on my VIM problem and there are a few other things it could be. If the signal on the video (mini RCA) for the red is too high the VNB might send a R-OVER Signal to cut the voltages to the tube to prevent damage. there are many factors it could be, a signal from the CLM, HDM, or even the VDM that is not right, causing the VIM to send an inhibit or spotkill to the tubes or HVPS. I have read over the marquee manuals many many times but still have a lot more to learn, I'm just scratching the surface of board level repair but its lots of fun, glad I got into this Hobby, the problems sometimes can be fun to figure out !
Athanasios
_________________
Don't blame your underwear for your crooked ass~ unknown Greek philosopher
"Republicans believe every day is the Fourth of July, but the Democrats believe every day is April 15." --- President Reagan
One Smart Dog!!!
Marquee High Performance Bellows now shipping!!
Marquee Modifications and Performance Enhancement
Marquee C-element and Bellow removal
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JustGreg
Joined: 07 Mar 2006
Posts: 3098
Location: Kenosha, WI
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| Posted: Wed Jul 02, 2008 4:16 pm Post subject: |
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| Nashou66 wrote: | That guide is for use with no scope just a multi meter(volt meter). TSE was also helping me out on my VIM problem and there are a few other things it could be. If the signal on the video (mini RCA) for the red is too high the VNB might send a R-OVER Signal to cut the voltages to the tube to prevent damage. there are many factors it could be, a signal from the CLM, HDM, or even the VDM that is not right, causing the VIM to send an inhibit or spotkill to the tubes or HVPS. I have read over the marquee manuals many many times but still have a lot more to learn, I'm just scratching the surface of board level repair but its lots of fun, glad I got into this Hobby, the problems sometimes can be fun to figure out !
Athanasios |
I initially had plans to 'do more' that just set up and watch my pj but a new job and the commute are sucking up what 'extra' time I used to have. Now I just want it to work when the monkey pushes the button.
Anyway, obviously something has failed along the chain to the VIM red RCA output. I'm not an EE or even an electronics hobbyist with credible skills so I'll probably end up biting the bullet and buying another one (VIM).
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Greg
"Is it ignorance or apathy? Hey, I don't know and I don't care!" --Jimmy Buffett
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Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
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