Beseler Dichro 45s color head repair

Gino Battiston · Aug 4, 2019

Hi!.
I´m having the Vactrol problem on my Dichro 45s color head. Founded some posts about the issue, but I cant figure out the actual modification needed to replace those vactrols nor their replacements. Any help would be very appreciated.

mshchem · Aug 4, 2019

I have some info I can try to dig up. I've replaced them on several heads that I no longer use/have. There's only one of the optical isolators that goes bad. I think, but not sure it's labeled iso 2 on the circuit board. These heads are so old other things start to break. The iso (opto coupler ) is a easy fix takes 10 -15 minutes to remove the board and a few minutes to solder the new one in place. The neon lamp fails, these are obsolete. Others have repaired the original iso,
25 years back I bought a few from a guy for a rather large sum, he was a surplus dealer. I don't think Vactrol has made these for 40 years. The modern versions have LED lamps that last forever.
There's a lot of threads on this. I will look tomorrow see what information I have. The part is USUALLY a small metal can about 8mm in diameter with 4 wires that are soldered to the board.

mshchem · Aug 5, 2019

Checked my notes. Everyone of these things eventually fail.

All the heads I fixed, four or five? I replaced the component, on the PCB, labeled ISO 2. The original part is a , Vactec 8646, Vactrol VTL 988. Beseler did repairs on these or offered parts until Beseler couldn't get them any longer. Beseler has changed ownership over the years. I don't think they can help with this really old stuff.

Your best bet is an electronics person who knows 1970's through 80's circuits. I know that the metal can can literally be carefully opened and the lamp replaced, that's way over my head.

Others on this site have been through this same problem.

Gino Battiston · Aug 5, 2019

mshchem said:
Checked my notes. Everyone of these things eventually fail.

All the heads I fixed, four or five? I replaced the component, on the PCB, labeled ISO 2. The original part is a , Vactec 8646, Vactrol VTL 988. Beseler did repairs on these or offered parts until Beseler couldn't get them any longer. Beseler has changed ownership over the years. I don't think they can help with this really old stuff.

Your best bet is an electronics person who knows 1970's through 80's circuits. I know that the metal can can literally be carefully opened and the lamp replaced, that's way over my head.

Others on this site have been through this same problem.

TKS mshchem
There´s a viable source of some vactrols here:
https://www.thonk.co.uk/shop/vactrols-vtl5c/
Don´t really know very much about electronics, but I guess those are not direct replacements.
I do need some help...

mshchem · Aug 5, 2019

Gino Battiston said:
TKS mshchem
There´s a viable source of some vactrols here:
https://www.thonk.co.uk/shop/vactrols-vtl5c/
Don´t really know very much about electronics, but I guess those are not direct replacements.
I do need some help...

Those are the modern LED version, it shows 4 wires, that makes sense. I have no idea what the specifications are of the original. Maybe there's a member here that can recommend the modern version.
These are simple devices, one side gets current to light up the lamp, one side has a photo sensor that detects the lamp.

mshchem · Aug 5, 2019

Gino Battiston said:
TKS mshchem
There´s a viable source of some vactrols here:
https://www.thonk.co.uk/shop/vactrols-vtl5c/
Don´t really know very much about electronics, but I guess those are not direct replacements.
I do need some help...

Correct, those don't resemble the outer appearance of the original. The original are small aluminum cans that are about 12mm tall, 8-9mm in diameter. I suspect that the modern versions would work great, if you knew which one to buy.

Tom Taylor · Friday at 1:34 PM

What's the symptoms of a bad vactrol in the Besseler 45s head?

Thomas

paul ron · Friday at 2:27 PM

delayed light or flickering or no light.

Tom Taylor · Friday at 3:02 PM

paul ron said:
delayed light or flickering or no light.

That sounds like I may have one. I use a floor switch and every now and then when I press it the timer starts counting down but the light seems to switch on a tad later. I thought that it may be due to the way I pressed down on the pedal since when I press firmly down the delay is not there.

paul ron · Friday at 3:57 PM

the vactrol has a small neon bulb to triger the photocell. if you ever had florecent lights with starters, you know how they flicker when old.

since we first started diagnosing this problem years ago, we discovered a modern fix using led opto islolators. i did have the part number but its been a long time and i cant even remember where i put my car keys today.

but you can do a search here to follow the updates and schematics. btw there are a couple variations on the color head that doesnt have this control board.

i asked rick for a few of his vactrols, perhaps you can use a couple yourself?

Beseler Dichro 45s color head repair

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