Beseler Dichro 45s Repair/Service Manual?

[CMoore]

. I have a color darkroom class this semester, and I'd like to have all our enlargers working instead of being 2 short...

Color.?
What school do you teach at young lady, and what is the process for an out of state student to enroll.?

 

[Mainecoonmaniac]

This the bulb I use for my Dichro 45S.
https://www.bhphotovideo.com/c/product/689614-REG/Impact_EVW_EVW_Lamp_250W.html/?ap=y&gclid=Cj0KCQjw1dGJBhD4ARIsANb6OdnsO88kHWK5BCReMOBQ68bSCXsl0b2kWF7Js4UjACWEeQrcZTQ9zwwaAgO2EALw_wcB&lsft=BI:514&smp=y

Here is the link for the manual.

http://www.silveruser.ca/Manuals/Beseler Dichro 45S.pdf

 

[mshchem]

I've had several of these heads never had a rash of bulbs blowing. Might be some bad bulbs? I have NOS GE bulbs. I would be wary of generic imports.

 

[Amanda B]

The Impact bulbs that Mainecoonmaniac linked to are the same ones I am using. We are testing one right now with a voltmeter and it is providing 103 volts to the bulb. Corrosion has been suggested as a possible cause, so that's our next step.
Stephen F. Austin State University in east Texas. We've got a pretty cool program, if I do say so myself.

 

[mshchem]

The Impact bulbs that Mainecoonmaniac linked to are the same ones I am using. We are testing one right now with a voltmeter and it is providing 103 volts to the bulb. Corrosion has been suggested as a possible cause, so that's our next step.
Stephen F. Austin State University in east Texas. We've got a pretty cool program, if I do say so myself.

Voltage of the bulbs is 82 volts.

 

[mshchem]

What is the line voltage? I have never looked at the voltage at the bulb. All my heads just specify EVW 82V 250W MAX.

 

[MattKing]

Welcome to Photrio.
This will start out as an aside - but humour me.
The colour heads for the Beseler 67 series evolved over many years. They too all use 82V bulbs, but the configuration for the power supplies varied over time.
in one fairly unfortunate configuration, the head connects to a necessary off-head power supply with a cord that has a standard household plug at the end - big mistake.
It is a mistake, because other versions of the head have the power supply built into the head, and they too have a cord with a standard household plug at the end.
The second, most modern version works great if you plug it directly into the wall.
If you plug the first type into the wall, the ~110 volts from the wall will cause the 82V bulb to blow.
I have direct, first hand experience with this.
I believe your problem is due to too high a voltage at the bulb. It would be prudent to check the power supply as well.

 

[Amanda B]

Thanks to everyone who is trying to help! I have 7 of these, all the same model. All plug into a timer that plugs into the wall and include a power source in the head. I have two on my dining room table right now trying to repair them. One is supplying 76 volts at the bulb, the other 103. I tried cleaning the connections with acetone but that made no difference.

 

[Mainecoonmaniac]

With all the difficulties with old technology, I’m wondering if an LED retrofit is feasible?

 

[mshchem]

Call Kevin Brown at KHB Photographix in Canada

http://www.khbphotografix.com/

Kevin knows Beseler stuff. That head is probably 30 years old or older.

 

[CMoore]

Call Kevin Brown at KHB Photographix in Canada

http://www.khbphotografix.com/

Kevin knows Beseler stuff. That head is probably 30 years old or older.

I will second this.
He was a big help to me.

 

[sasah zib]

Thanks to everyone who is trying to help! I have 7 of these, all the same model. All plug into a timer that plugs into the wall and include a power source in the head. I have two on my dining room table right now trying to repair them. One is supplying 76 volts at the bulb, the other 103. I tried cleaning the connections with acetone but that made no difference.

perhaps someone from your engineering school could help. it could turn into some combination project.

 

[Amanda B]

Thank you all for your concern and helpfulness. I exchanged emails with Kevin but I'm going to try to get it fixed a little faster than shipping to Canada would allow before I fall back on that option. A colleague who is a retired electrician is coming to look things over with me on Friday. I was able to find a schematic online for some Chromegatrol timers that I am having trouble with, but I haven't been able to get a schematic for this enlarger head. Does anyone have a schematic to share?
Thanks again!

 

[Mainecoonmaniac]

Thank you all for your concern and helpfulness. I exchanged emails with Kevin but I'm going to try to get it fixed a little faster than shipping to Canada would allow before I fall back on that option. A colleague who is a retired electrician is coming to look things over with me on Friday. I was able to find a schematic online for some Chromegatrol timers that I am having trouble with, but I haven't been able to get a schematic for this enlarger head. Does anyone have a schematic to share?
Thanks again!

Here's a link to IFixit. There's a schematic on the page.
https://www.ifixit.com/Answers/View/664116/Repair+Beseler+Dichro+45s+circuit+board.

 

[scherbis]

My local community darkroom had a 45s blowing bulbs as soon as it is turned on. Did anyone ever find a service manual?

 

[xkaes]

I just ran across this 20-year-old thread, and I have the same problems as others -- a lag in the bulb turning ON. I've learned to live with it, but now that I realize many others have this problem -- and are having a hard time getting the details they need to fix it -- I have to ask:

Is there a website that outlines how to fix this problem?

If not, can anyone explain what I need to do to fix it? I'll take it and post it on MY website for everyone to see.

 

[Dirb9]

I just ran across this 20-year-old thread, and I have the same problems as others -- a lag in the bulb turning ON. I've learned to live with it, but now that I realize many others have this problem -- and are having a hard time getting the details they need to fix it -- I have to ask:

Is there a website that outlines how to fix this problem?

If not, can anyone explain what I need to do to fix it? I'll take it and post it on MY website for everyone to see.

Check out this thread here on photrio and this recent one on reddit. Not quite a walkthrough, but does include circuit diagrams and the replacement part number.

 

[mshchem]

Check out this thread here on photrio and this recent one on reddit. Not quite a walkthrough, but does include circuit diagrams and the replacement part number.

Yes, it's the Iso 2 optocoupler. The thread indicates a more modern replacement. Very easy to fix with a small soldering iron.

 

[Kelly Bruce]

My Beseler 45 Dichro (Computerised) just died. Does anyone have a maintenance manual they could share please?
Local technician won't touch it without a circuit diagram.
Thanks in advance.

 

[xkaes]

I think there is a link in an earlier message on this thread -- if not try the thread mentioned above from mshchem on photrio.

When you say "DIED", do you mean it won't turn on -- or it doesn't "work"? Do you have the user manual?

Is it a DICHRO 45 S or another model?

 

[Kelly Bruce]

Schematic for the power supply sent via e-mail.

Hi Ron. I found this old thread, hoping it's still active.
My Beseler 45 Dichro Computerised Colour head just died, and I've been unable to find maintenance manuals or circuit drawings for it.
Please advise if possible to assist.
Many thanks

 

[btaylor]

Kelley, is this the head you have? Much of this discussion is of the Dichro 45 S head, which differed from the Dichro 45 Color Computer, of which I have a couple of copies. If you have one like mine, I may be able to help depending on your “died” circumstances. I posted earlier in this thread about the circuit board connection issues. The head in my photo has “died” multiple times. Lamp wouldn’t come on when it should (be aware of the paper saver white light lever) or the YMC readouts would be crazy and flicker. Every time this happens I think “oh boy, this is it, we’re done,” and every time plugging and unplugging and wiggling the 3 circuit boards has brought it back to life except the most recent failure. I poked around because the lamp wouldn’t come on. No dice. Finally I checked the simplest thing- the lamp itself- and found I had a blown bulb! Good luck and please identify both your exact head and exactly what the failure is. We may be able to help.

 

[btaylor]

Hi Ron. I found this old thread, hoping it's still active.
My Beseler 45 Dichro Computerised Colour head just died, and I've been unable to find maintenance manuals or circuit drawings for it.
Please advise if possible to assist.
Many thanks

paul ron hasn’t been on this board since April ‘22, so he may not see your post.

 

[Kelly Bruce]

View attachment 334982
Kelley, is this the head you have? Much of this discussion is of the Dichro 45 S head, which differed from the Dichro 45 Color Computer, of which I have a couple of copies. If you have one like mine, I may be able to help depending on your “died” circumstances. I posted earlier in this thread about the circuit board connection issues. The head in my photo has “died” multiple times. Lamp wouldn’t come on when it should (be aware of the paper saver white light lever) or the YMC readouts would be crazy and flicker. Every time this happens I think “oh boy, this is it, we’re done,” and every time plugging and unplugging and wiggling the 3 circuit boards has brought it back to life except the most recent failure. I poked around because the lamp wouldn’t come on. No dice. Finally I checked the simplest thing- the lamp itself- and found I had a blown bulb! Good luck and please identify both your exact head and exactly what the failure is. We may be able to help.

Thanks for replying.
Yes, that image is the same as mine.
It started with delays, then when warm would illuminate un-commanded, and sometimes will switch off during an exposure.
Then last week as soon as I powered the machine, it's bulb came on, & wouldn't switch off, regardless of what position the white light lever is in.

I stripped it and found some mechanical issues on the filter mechanism which were an easy fix. Some of the plastic gears were loose, and weren't rotating, ie not returning to full zero when dialed back. Some secured with circlips which had worked loose allowing the gear to move forward & disengage from the gear on the drive shaft, (Cyan) others worn, & not turning under load. A dab of CA sorted that all out.
I removed the boards, cleaned all the contacts, and visually inspected everything. No apparent faults, identified, reassembled, no luck.
The bulb is now off, and it won't switch on. Checked the lamp, it's fine.
I tried another timer, no change.
A local electronics repair guy is willing to look at it but only with supporting circuit diagrams.
Any help or suggestions appreciated.

 

[btaylor]

Thanks for replying.
Yes, that image is the same as mine.
It started with delays, then when warm would illuminate un-commanded, and sometimes will switch off during an exposure.
Then last week as soon as I powered the machine, it's bulb came on, & wouldn't switch off, regardless of what position the white light lever is in.

I stripped it and found some mechanical issues on the filter mechanism which were an easy fix. Some of the plastic gears were loose, and weren't rotating, ie not returning to full zero when dialed back. Some secured with circlips which had worked loose allowing the gear to move forward & disengage from the gear on the drive shaft, (Cyan) others worn, & not turning under load. A dab of CA sorted that all out.
I removed the boards, cleaned all the contacts, and visually inspected everything. No apparent faults, identified, reassembled, no luck.
The bulb is now off, and it won't switch on. Checked the lamp, it's fine.
I tried another timer, no change.
A local electronics repair guy is willing to look at it but only with supporting circuit diagrams.
Any help or suggestions appreciated.

Wow, that’s a lot of weird faults, and they don’t seem to match up with the pattern failures mentioned on this and other similar threads. Given the cost of making a proper repair (in either time or money) I think the solutions given on post #46 would be easier, and cheaper. I would think your electronics friend could put it together easily. It hardly seems worthwhile to track down failed components on 3 circuit boards. I picked up a spare head a few years ago for $100, but I see broken ones on eBay for $400 now. I don’t find the electronics to really add much value, all I really want are the 3 filters, a way to index them and an appropriate light source. Another thought would be to get a Beseler Dichro dg head. It’s fully mechanical, as long as the bulb lights up you should be good to go. Note that there was a link to a schematic at Ifixit earlier in this thread but I don’t think it pertains to your model head. Best of luck and if and when you find your solution please post back here with your answer. Best of luck!