Beseler 45 computer controlled color head alignment issue

Hello,

I recently got hold of a Beseler 45 Dichromatic computer controlled color head. Everything works more or less fine with the exception that I can't dial in the Yellow filter to 0. The lowest I can adjust it to using the adjustment screws at the underside of the head is 32.
The interesting part is that dialing in a combination of Magenta and Cyan will get Yellow and the other two to 0.
This however results in colder more blueish light as if all three filters were just set fully CCW or the white light lever pulled.

A call to Beseler was rather disappointing in that they say they discarded all documentation with the move in 2008, which I found interesting that schematics weren't digitized, and also nobody seems to be around anymore who would even know anything about the old heads.

Hoping to find somebody on this forum who may have come across a set of schematics for the filter control or would have an idea how to fix this. For now my workaround is to simply add 32 to the Yellow amount depending which filter I want to dial in for B/W printing.

Cheers,
Michael

Discarding documentation? Not the first time for Beseler, and probably not accidental either. They really don't like dealing with service issues on any kind of older models.

DREW WILEY said:

Discarding documentation? Not the first time for Beseler, and probably not accidental either. They really don't like dealing with service issues on any kind of older models.

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Apparently they moved offices in 2008 and discarded all materials pertaining to products no longer supported. Given the history of the company it's strange to do that as it would be relevant in the future as
historical artifacts to document. Also interesting that no digital copies are apparently available. It could also be that she simply didn't want to give me the time of day as I was obviously not interested in
buying a brand new $4000+ color head.

First testing showed that similar results can be had between all dials CCW and dialing in 000 across all three displays/ filters with the biggest difference that the latter approach requires twice the exposure time.

Wondering if the sensor atop the diffusion chamber might be the culprit.

I have one these heads, I don't use it though. I did see a similar problem in zeroing the yellow. My suspect at the time was either the filter in the sensor or maybe the foam in the mixing box had yellowed. Not much help I know but you are not alone.

So you have no owner's manual or service manual? I do know the competitor's system (Omega D5500) has 3 places for tuning the response of each color channel.
1) The actual Wratten filter over the sensor
2) The internal trimmer to calibrate the photocell
3) The external trimmer to zero the channels every month or so.

I had to adjust all three on some of my enlargers. For example look at how there is a difference in the green filter on one of my sensor probes. I replaced that with a new green Wratten and re-calibrated to optimize my Magenta channel response.

In your case there may be an issue with the calibration or filter of your blue sensor.

The computer controlled model is a pain. The old and newer dichro 45S models can be kept alive.

Same problem exists with the really cool Beseler 45 Universal. I have these, computer controlled RGB closed loop heads. This was Beseler's last attempt to stay competitive with the competition.

Beseler changed ownership and no longer support this stuff. Try calling KHB Photographix, Kevin Brown. He will give you the facts.

mshchem said:

The computer controlled model is a pain. The old and newer dichro 45S models can be kept alive.

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Not sure I would agree with your statement about the older heads. The reason I got this one because the older head I have was no longer working reliably.
The Magenta dial was no longer stopping so could be turned without knowing which value was actually dialed in which led to extra turning to make sure it's
on zero and go from there. These heads in general are a PITA to work on.

I'll give KHB a call, maybe they have an answer to the problem. Thanks for the tip.

Cheers,
Michael

ic-racer said:

So you have no owner's manual or service manual? I do know the competitor's system (Omega D5500) has 3 places for tuning the response of each color channel.
1) The actual Wratten filter over the sensor
2) The internal trimmer to calibrate the photocell
3) The external trimmer to zero the channels every month or so.

I had to adjust all three on some of my enlargers. For example look at how there is a difference in the green filter on one of my sensor probes. I replaced that with a new green Wratten and re-calibrated to optimize my Magenta channel response.

In your case there may be an issue with the calibration or filter of your blue sensor.

View attachment 247443

Click to expand...

I do have the user manual which of course is useless in terms of real troubleshooting. No service manual which would help of course.

mschulz said:

Not sure I would agree with your statement about the older heads. The reason I got this one because the older head I have was no longer working reliably.
The Magenta dial was no longer stopping so could be turned without knowing which value was actually dialed in which led to extra turning to make sure it's
on zero and go from there. These heads in general are a PITA to work on.

I'll give KHB a call, maybe they have an answer to the problem. Thanks for the tip.

Cheers,
Michael

Click to expand...

The last head Beseler made (before this new LED head) is a updated Dichro 45S. Nothing fancy but free from the problems of the older models. These were still available new up to a few years back. I have one of these as my backup, it's a nice head made early 2000's. Got it from someone who bought a brand new enlarger from B&H.
The best hope is KHB.

mshchem said:

The last head Beseler made (before this new LED head) is a updated Dichro 45S. Nothing fancy but free from the problems of the older models. These were still available new up to a few years back. I have one of these as my backup, it's a nice head made early 2000's. Got it from someone who bought a brand new enlarger from B&H.
The best hope is KHB.

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The 45S is what I have retired into storage for now. Probably will sell it eventually for parts. The Dichro 45 Computer Controlled replaced that. I had an email exchange with a former engineer at Beseler who worked on the CC head.
He basically told me to re-flow the solder joints on the boards as those will go bad over the years, especially when those heads aren't shipped properly. So will take that course once I find some time. Hope this will resolve the issue.

mschulz said:

The 45S is what I have retired into storage for now. Probably will sell it eventually for parts. The Dichro 45 Computer Controlled replaced that. I had an email exchange with a former engineer at Beseler who worked on the CC head.
He basically told me to re-flow the solder joints on the boards as those will go bad over the years, especially when those heads aren't shipped properly. So will take that course once I find some time. Hope this will resolve the issue.

Click to expand...

No argument. By 1990 Beseler was promoting the Minolta pulsed Xenon color head, by 2001 Beseler produced the Universal 45 system, 3 lamps, red, green, and blue fixed dichro filters. This is what I have. Two controllers were available. A color controller or a variable contrast controller. These heads are the best head Beseler ever made. By the early 2000's Beseler was also making a re-designed Dichro 45S, this had more reliable electronics than the first generation that proceeded your 1980s vintage Computerized Color head. Bottom line the only reasonably reliable head made by Beseler is the new LED head and the Dichro S heads that were made in the last 10 years or so.

30, 40, 20 year old electronics. Pretty hard to keep going. If you can find very lightly used examples, that's great.

mshchem said:

No argument. By 1990 Beseler was promoting the Minolta pulsed Xenon color head, by 2001 Beseler produced the Universal 45 system, 3 lamps, red, green, and blue fixed dichro filters. This is what I have. Two controllers were available. A color controller or a variable contrast controller. These heads are the best head Beseler ever made. By the early 2000's Beseler was also making a re-designed Dichro 45S, this had more reliable electronics than the first generation that proceeded your 1980s vintage Computerized Color head. Bottom line the only reasonably reliable head made by Beseler is the new LED head and the Dichro S heads that were made in the last 10 years or so.

30, 40, 20 year old electronics. Pretty hard to keep going. If you can find very lightly used examples, that's great.

Click to expand...

I'm sure the new LED heads are nice. But they aren't nice enough for me to make me shell out over $4000 for one. Most of my work right now is in color which I no longer print in the darkroom
but on my Epson P-8000 which does a pretty good job in combination with Hahnemuehle papers. Even b/w prints are getting close, just not close enough yet when compared side by side to
silver.

40 year old electronics? HAHAHA .. .I'm a ham, old radios are very common. But yes, it's harder to find parts. But most important is documentation.

mschulz said:

I'm sure the new LED heads are nice. But they aren't nice enough for me to make me shell out over $4000 for one. Most of my work right now is in color which I no longer print in the darkroom
but on my Epson P-8000 which does a pretty good job in combination with Hahnemuehle papers. Even b/w prints are getting close, just not close enough yet when compared side by side to
silver.

40 year old electronics? HAHAHA .. .I'm a ham, old radios are very common. But yes, it's harder to find parts. But most important is documentation.

Click to expand...

Ham, then you've got this down! Yes the documentation is key. When Beseler changed ownership last, they must have made a point of trashing all the old documents. My stuff is from 2002-2005 time frame there's nothing. I agree that your Epson is pretty hard to beat making color prints.
The old Dichro 45S had a opto-isolator that went bad, a Vactrol neon job. This causes the lamp to delay when switched on, totally randomly. When Beseler was still Beseler I got ahold of a guy in their service department that told me what I needed, they had long since given up as the parts were obsolete. This was at least 20 years back, I found a guy in NYC that had a warehouse full of old components. He dealt in bulk, but he sold me 10 of the little buggers. 4 leads, solder it to the board worked perfectly. I fixed at least 4 of these things. Those are all still in use by young fellas I hooked up with enlargers. Here's what fixed the delay.

mshchem said:

Ham, then you've got this down! Yes the documentation is key. When Beseler changed ownership last, they must have made a point of trashing all the old documents. My stuff is from 2002-2005 time frame there's nothing. I agree that your Epson is pretty hard to beat making color prints.
The old Dichro 45S had a opto-isolator that went bad, a Vactrol neon job. This causes the lamp to delay when switched on, totally randomly. When Beseler was still Beseler I got ahold of a guy in their service department that told me what I needed, they had long since given up as the parts were obsolete. This was at least 20 years back, I found a guy in NYC that had a warehouse full of old components. He dealt in bulk, but he sold me 10 of the little buggers. 4 leads, solder it to the board worked perfectly. I fixed at least 4 of these things. Those are all still in use by young fellas I hooked up with enlargers. Here's what fixed the delay.
View attachment 247543

Click to expand...

Vactrols are still very common for a variety of applications. As a hobby other than ham radio I spend time (and money) building modular synthesizer modules. Vactrols are great for isolation purposes. One can even build them
from an LED and an LDR.

The great thing about inkjet color printing is the paper selection. For normal darkroom use all that's essentially left seems to be Fuji.

Now if that project list would get shorter instead of longer, that'd be nice.

mschulz said:

Vactrols are still very common for a variety of applications. As a hobby other than ham radio I spend time (and money) building modular synthesizer modules. Vactrols are great for isolation purposes. One can even build them
from an LED and an LDR.

The great thing about inkjet color printing is the paper selection. For normal darkroom use all that's essentially left seems to be Fuji.

Now if that project list would get shorter instead of longer, that'd be nice.

Click to expand...

Yeah I have more projects than I can accomplish in the next 2 lifetimes. I cling to the analog stuff because it's so lovely. RA4 is something I do quite rarely anymore. I love printing black and white, old school fiber base. Still shoot some E6 because I love it, and love processing reversal film.
There's five enlargers set up in this shot with my Thomas safelights going. I'm just glad I don't collect steam engines