| Author |
Message |
mp20748
Joined: 12 Sep 2006
Posts: 5689
Location: Maryland
TV/Projector: 9500LC Ultra / Super 02 and 03 VIM
|
| Posted: Tue Nov 06, 2007 4:32 pm Post subject: Yo Curt.. have you seen this problem... |
|
|
I'm having a problem on my shop (test unit) 8500 Ultra.
The problem is IC 'U900' on the vertical deflection board. I've replaced that IC about 4 times. I've swapped out the board twice. I've even replaced the yoke that it connects to.
Whatever I do, it seems to keep blowing that IC, and when it does, it also takes out resistor 'R920'.
I'm running out of the chips, and I don't want to put in another VDM until I can get to the bottom of this.
I've checked the heatsink and the clip that holds the chips to the heatsink. I've also looked at the isolator, but did not notice anything unusual.
Help!
|
|
| Back to top |
|
 |
Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
|
| Posted: Tue Nov 06, 2007 4:47 pm Post subject: |
|
|
|
Hm, no, but let me check the schematic. The only thing I had happen on one MArquee that took out a number of HDMs was a ground strap that came loose on the bell of one tube, causing HV arcing, not very loud, but enough to take out the HDM FET a few times before I heard the 'tick' of the HV arc...
|
|
| Back to top |
|
|
Tim in Phoenix
Joined: 21 Oct 2006
Posts: 4409
Location: Phoenix
|
| Posted: Tue Nov 06, 2007 6:10 pm Post subject: |
|
|
Say Mike
Put a meter from the IC tab to ground, maybe the insulation tape is scuffed; were you swapping boards on the heat sink?
|
|
| Back to top |
|
|
oliverg
Joined: 15 May 2007
Posts: 800
Location: Melbourne, Australia
TV/Projector: Sony G90 X2 - Vidikron Vision 1
|
| Posted: Tue Nov 06, 2007 6:26 pm Post subject: |
|
|
Mike - from what I've seen, the Electrohome boards are all very susceptible to flashover.
Over the years, safeguards have been adopted and seemingly each revision and ISS have more and more field mods to make them more robust. Is this a manifestation of a similar problem?
Kind regards
_________________
( R ) G ( G ) 9 ( B ) 0 ( R ) G ( G ) 9 ( B ) 0
( R ) G ( G ) 9 ( B ) 0 ( R ) G ( G ) 9 ( B ) 0
|
|
| Back to top |
|
|
Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
|
| Posted: Tue Nov 06, 2007 6:58 pm Post subject: |
|
|
|
WEll the Ulta is about as late a board set as you can get. The only time I've seen a smoked V board is usually when someone (me included) does something wrong when doing the anamorphic squeeze mod.
|
|
| Back to top |
|
|
mp20748
Joined: 12 Sep 2006
Posts: 5689
Location: Maryland
TV/Projector: 9500LC Ultra / Super 02 and 03 VIM
|
| Posted: Tue Nov 06, 2007 7:22 pm Post subject: |
|
|
I got it working again!!!
But I doubt that I've solved the original problem.. 
I think I'm safe as long as I don't put the heatsink back up and screw it in place. Not sure what's causing this. and I don't want to risk blowing another IC, though this last time it was only the 1 ohm resistor.
The insulator looks OK, and I've even poked it with the probe of my Fluke hoping to read short/leaking along its surface - nothing!
For now..
Last edited by mp20748 on Tue Nov 06, 2007 7:48 pm; edited 1 time in total
|
|
| Back to top |
|
|
Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
|
| Posted: Tue Nov 06, 2007 7:39 pm Post subject: |
|
|
|
Also check to see that the plastic strip between the heatsink and motherboard connectors is in place. Flipping that heatsink up with the strip punctured or being loose can cause the multipin connector to short to the heatsink assembly. HAd that happen once.
|
|
| Back to top |
|
|
JustGreg
Joined: 07 Mar 2006
Posts: 3098
Location: Kenosha, WI
|
| Posted: Tue Nov 06, 2007 8:00 pm Post subject: |
|
|
I'd modify line conditioners....it's possible you're the victim of a diabolical underground resistance group who surreptitiously directs nano bots (Digital Disease) to seek out analog devices capable of producing results superior to those of their creator, King Xenon, and destroying the victim from within via an overwhelming mass of
1010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101
1010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101
1010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101
1010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101
1010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101
1010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101
1010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101
1010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101
1010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101
1010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101
1010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101
1010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101
1010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101
1010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101
1010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101
1010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101
1010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101
1010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101
1010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101
1010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101
1010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101
1010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101
1010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101
1010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101
1010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101
1010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101
1010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101
1010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101
1010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101
1010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101
1010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101
1010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101
Or, it could just be a flaky ground.
It almost sounds like the flexing problems that goes on with the X clamp on an XB360.
_________________
Greg
"Is it ignorance or apathy? Hey, I don't know and I don't care!" --Jimmy Buffett
|
|
| Back to top |
|
|
mp20748
Joined: 12 Sep 2006
Posts: 5689
Location: Maryland
TV/Projector: 9500LC Ultra / Super 02 and 03 VIM
|
| Posted: Tue Nov 06, 2007 8:02 pm Post subject: |
|
|
| Curt Palme wrote: | | Also check to see that the plastic strip between the heatsink and motherboard connectors is in place. Flipping that heatsink up with the strip punctured or being loose can cause the multipin connector to short to the heatsink assembly. HAd that happen once. |
That was my first thought, but the connector on the Ultra's mother board is different (see below).
|
|
| Back to top |
|
|
mp20748
Joined: 12 Sep 2006
Posts: 5689
Location: Maryland
TV/Projector: 9500LC Ultra / Super 02 and 03 VIM
|
| Posted: Tue Nov 06, 2007 8:09 pm Post subject: |
|
|
| JustGreg wrote: | I'd modify line conditioners....it's possible you're the victim of a diabolical underground resistance group who surreptitiously directs nano bots (Digital Disease) to seek out analog devices capable of producing results superior to those of their creator, King Xenon, and destroying the victim from within via an overwhelming mass of
|
One day I'm going to get me one of those things that those strange folk use to detect ghost in buildings. It seems that they use a Fluke meter attached to a coil of wire...
I think once I do that, I'm sure I'll get to the bottom of things, because it must be ghost shorting out those IC's. I just need to figure out what to set the Fluke to, and what gauge of wire to use to connect to the coil of wire..
|
|
| Back to top |
|
|
stefuel
Joined: 07 Mar 2006
Posts: 3353
Location: Green Harbor MA USA
|
| Posted: Tue Nov 06, 2007 11:21 pm Post subject: |
|
|
I think that's the same batch of ic's that AmPro's QC team rejected 
_________________
Chip
A Barco is only a AmPro with training wheels
Card carrying member of the AVS chain gang.
|
|
| Back to top |
|
|
mp20748
Joined: 12 Sep 2006
Posts: 5689
Location: Maryland
TV/Projector: 9500LC Ultra / Super 02 and 03 VIM
|
| Posted: Wed Nov 07, 2007 1:15 am Post subject: |
|
|
| stefuel wrote: | | I think that's the same batch of ic's that AmPro's QC team rejected |
what's an Ampro??
|
|
| Back to top |
|
|
stefuel
Joined: 07 Mar 2006
Posts: 3353
Location: Green Harbor MA USA
|
| Posted: Wed Nov 07, 2007 1:50 am Post subject: |
|
|
| mp20748 wrote: | | stefuel wrote: | | I think that's the same batch of ic's that AmPro's QC team rejected |
what's an Ampro?? |
Well, if a G-90 is a Cadillac and a Marquee is a lincoln, A AmPro is a Rolls Royce 8)
_________________
Chip
A Barco is only a AmPro with training wheels
Card carrying member of the AVS chain gang.
|
|
| Back to top |
|
|
mp20748
Joined: 12 Sep 2006
Posts: 5689
Location: Maryland
TV/Projector: 9500LC Ultra / Super 02 and 03 VIM
|
| Posted: Mon Nov 26, 2007 12:53 pm Post subject: |
|
|
A couple of weeks and the last two days mainly devoted to this problem and BINGO!
last night around 9PM..
|
|
| Back to top |
|
|
Tim in Phoenix
Joined: 21 Oct 2006
Posts: 4409
Location: Phoenix
|
| Posted: Mon Nov 26, 2007 4:51 pm Post subject: |
|
|
So Mike
What was the problem?
.
|
|
| Back to top |
|
|
Fujifrontier
Joined: 20 Oct 2007
Posts: 354
Location: San Antonio, Texas
|
| Posted: Tue Nov 27, 2007 2:24 am Post subject: |
|
|
|
we demand answers
|
|
| Back to top |
|
|
stefuel
Joined: 07 Mar 2006
Posts: 3353
Location: Green Harbor MA USA
|
| Posted: Tue Nov 27, 2007 10:40 am Post subject: |
|
|
He traded up to a Rolls Royce 
_________________
Chip
A Barco is only a AmPro with training wheels
Card carrying member of the AVS chain gang.
|
|
| Back to top |
|
|
Heywood Jablome
Joined: 12 Mar 2006
Posts: 1548
|
| Posted: Tue Nov 27, 2007 9:33 pm Post subject: |
|
|
Rolls Canhardly?
_________________
"Those countries which lag behind in industry, in the application of mechanics and technical chemistry, in the careful selection and utilization of natural products, where the respect for such activities does not permeate all classes of society, will unfailingly decline in prosperity. They will sink faster when neighbor states, with an energetic exchange between science and industry, go forward with renewed vitality."
-- Baron Alexander von Humboldt: 1769-1859
|
|
| Back to top |
|
|
Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
|
| Posted: Tue Nov 27, 2007 9:43 pm Post subject: |
|
|
He posted at 5 AM. I think he's sleeping..
|
|
| Back to top |
|
|
|
|
