CurtPalme.com Home Theater Forum

[Curt Palme]

So I get this Barco in that got hit, probably before it even got shipped from the looks of it. The lenses got pushed in so hard that they sheared off the metal pins and the lens barrels got smashed into the tube faces, smashing all of those. (I should have taken a picture with lenses off, sorry!)

Fortunately the G and B tubes were toast anyways, so no big deal really. Little drops of glycol were everywhere, mostly on the convergence tray, a tiny bit on the motherboard and surrounding metal, none got into the card cage.

So I fired the set up and found that the red tube had cracked, but I figured the set more or less worked since I got HV and that meant that 90% of the set was working. So I retubed with some nice tubes I had here, and fired the set up. It worked, but I smelled smoke (burned resistor) and the red V shift was jumping. Narrowed it down to the convergence board. Replaced the driver and the output board, the spares didn't work quite right, variations on the driver board.

So I figure I'd pull the HV section and let the set run, maybe whatever was bad would smoke itself out.

I spent 4 hours working on the damn convergence tray. Cleaned the boards 4 X, flushed them with isopropyl. Finally swapped out a convergence tray from a working set, and that worked fine for hours, so it was a problem with the original tray. The boards are squeaky clean by now.

So the output board smoked a couple of resistors overnight, so I pulled the tray again. I replace the resistors, and decided to change the output chip in case it was intermittent.

Turns out there were a couple of droplets of glycol right around the pins of hte chip, and since the chips is sort of protected by the heatsink it's on, my flushing never got to the chip pins.

Cleaned everything again and changed the chip, and it's fine.

So a word of caution, if you ever spill glycol onto a board that has more than a couple of volts on it, you're probably screwed, and need a new board.

Lesson learned here..

[Curt Palme]

So I get this Barco in that got hit, probably before it even got shipped from the looks of it. The lenses got pushed in so hard that they sheared off the metal pins and the lens barrels got smashed into the tube faces, smashing all of those. (I should have taken a picture with lenses off, sorry!)

Fortunately the G and B tubes were toast anyways, so no big deal really. Little drops of glycol were everywhere, mostly on the convergence tray, a tiny bit on the motherboard and surrounding metal, none got into the card cage.

So I fired the set up and found that the red tube had cracked, but I figured the set more or less worked since I got HV and that meant that 90% of the set was working. So I retubed with some nice tubes I had here, and fired the set up. It worked, but I smelled smoke (burned resistor) and the red V shift was jumping. Narrowed it down to the convergence board. Replaced the driver and the output board, the spares didn't work quite right, variations on the driver board.

So I figure I'd pull the HV section and let the set run, maybe whatever was bad would smoke itself out.

I spent 4 hours working on the damn convergence tray. Cleaned the boards 4 X, flushed them with isopropyl. Finally swapped out a convergence tray from a working set, and that worked fine for hours, so it was a problem with the original tray. The boards are squeaky clean by now.

So the output board smoked a couple of resistors overnight, so I pulled the tray again. I replace the resistors, and decided to change the output chip in case it was intermittent.

Turns out there were a couple of droplets of glycol right around the pins of hte chip, and since the chips is sort of protected by the heatsink it's on, my flushing never got to the chip pins.

Cleaned everything again and changed the chip, and it's fine.

So a word of caution, if you ever spill glycol onto a board that has more than a couple of volts on it, you're probably screwed, and need a new board.

Lesson learned here..

[perisoft]

There once was a technician like all
who decided to clean off some glycol...

[Curt Palme]

Worked on it for days
His brain in haze
From banging his head on the wall.

[Curt Palme]

Worked on it for days
His brain in haze
From banging his head on the wall.

[JustGreg]

[Tom.W]

By the way the antidote for swallowing glycol is alcohol

[stefuel]

[Tom.W]

You definatelly won Chip but can't remember what ? Must be the alcohol ...

[paw]

[Fujifrontier]

explain how this vodka cure works, please

[AnalogRocks]

He'd tell you but he can't remember after taking the cure.

[AnalogRocks]

He'd tell you but he can't remember after taking the cure.

[rabies_70]

The ethanol alcohol (vodka gin whatever) competitively binds with alcohol dehydrogenase in the kidneys and the gycol is then harmlessly excreted before it can metabolize the nasties that cause renal failure and death (usually around 24-72 hours). Old school treatment., they usually have to do dialysis as well now. Glycol is so rapidly absorbed and the initial symptoms mimic alcohol intoxication that diagnosis is some times late. That and the lethal dose can be as little as 2 tablespoons in an average adult.