Beseler Dichro 45S Troubleshooting

New light source does not seem to work.

I have a Beseler 45 VXL with a Dichro 45 S light source. I just picked up a second enlarger off of Ebay that is a Beseler 45MXT with the same Dichro 45S light source.

The new light head looks newer and cleaner than my original. It is not the computerized version. It has no dust or other damage and looks about mint. It did not have a bulb in it but the fan powered on. Today, I brought it home, put in a new bulb, fired on the fan, and then plugged in the light source. Unfortunately, nothing happens. It never lights up. I put the white light lever off so that is not an issue. The dim lights for the filtration knobs do not light up. The "white light" warning light does work and the fan works.

I tried two different bulbs, inserted them multiple times. The contacts were clean and well seated. When I plugged in the light source, the unit did make a vague thump sound when it received power but nothing remarkable.

I did have the unit on its side (now that I think about it) and it was separate from the enlarger but I don't know why that would matter. Any advice? I am hoping I am missing something obvious. Thanks.

J Harter

Hello Dr. Harter,

Not a solution but I have two just like it sitting in my shop. I spent so much time trying to get one to work that I finally just decided that it wasn't going to be. I contacted Beseler but they were no help. I have an extensive mechanical and electrical background but couldn't revive them. I hope you discover something, I always think I missed something, after all they don't work.

Curt

I have found that the 45S malfunctions sometimes if contacts on the circuit boards get dirty. Cleaning them has fixed it so far for me.

PE

I meticulously removed and cleaned each socket and board contact to no avail. Granted it may have worked for some but there can be units that a fine cleaning is not enough. It could be a fault in any part of the circuit board or component.

Curt

What do you remove to access the circuit board for cleaning? Does cleaning consist of blasting with compressed air while vacuuming the dust away or should I try something else? Thanks.

J Harter

Can either one of you send me one of these thing? I really want to try to fix one.

check the resistor and move it to high.

i had some issues with the light and discovered the voltage was on low.

can't hurt to check.

On top of the 45S, is a door about 8x10" in size and opened by two screws. That door is hinged.

Open it and looking down on the head, the cards are on the left and the filters are on the right front, and the lamp is on the right middle, while the light box and sensor is in the middle.

The cards are held in place by a retainer that screws into the support structure. Removing the screw (and not dropping it down into the guts), you can then remove the retainer, and access the cards. They can be removed and the contacts can be cleaned with a pencil eraser. These look just like computer cards (which they are) with little fingers on the end. The bus is at the bottom of the head.

I've found that sometimes, just rocking the cards back and forth fixes the problem.

PE

First of all, you need to take a voltmeter and determine whether you have lamp voltage from the main supply. If so, trace onward to the "white light switch". This is a notoriously aggrevating component, and switch contacts can go bad, or the mechanical alignment off. If voltage follows through, keep tracing toward the lamp socket until the problem is found. Most of the problems with these are to be found in the main power supply source circuit for the unit. But, you cannot troubleshoot without a voltmeter, and until you do is sort of like three shade tree mechanics walking around a car with the hood down wondering what is wrong with the motor when it wont start...