Beseler 45MXR Motor Drive failing, Plus some questions

Hi, I've come to be in possession of a Beseler 45MXR recently, and while I do eventually plan to either set it up in my apartment, or store it there till I move somewhere I can set a proper darkroom up in, I currently have it set up in my university's Darkroom (very few folks use it, and I've been given permission to set it up in my own corner of the room). Firstly, it's amazingly better than the rickety old Omega B&Ws that my university has, but a few issues have shown up. Firstly the Resistrol unit gets rather warm under use, and makes a sort of smell you don't want your electronics to make. Secondly, the motor drive has pretty much started to fully fail, and almost no upwards movement is accomplished (it's faster to manually turn the heavily geared pully instead). With the Beseler, a second motor drive, in a state of disassembly, was included, as well as a second resistrol unit. Both resistrol units have the same smell issue. I beilve the heat is just a function of a resistrol, obviously introducing resistance into the circuit will generate heat, but is the smell normal?

From a breif bit of research, it appears that it's common for belt drives to have issues on 45MXs, but I'm wondering if the solution would be to try and pull parts from the second drive unit that came with my enlarger, because I would figure that's what the previous owner did already.

The final question I have on this, is, how easy would it be to rewire the unit to be grounded? I'm rather wary of using an ungrounded metal bodied machine that is directly carrying mains voltage. The Omegas i've used before are all grounded.

The Resistrol is a simple dimmer switch, Beseler got rid of this in the 70's. No grounded plug means 1950's , the enlarger should be grounded. Very simple to do if you have the proper cord, strain relief (parts) and know how.
You can run a small extension cord directly to the 2 prong lamp plug and then plug this into your timer (if you have a timer)

Sometimes when transporting the enlarger can get out of sync and the motor will labor to move it up and down.

I would use the Resistrol on full power, or eliminate it entirely.

Ollingers Guide to enlargers is on the internet with manuals for Beseler.

I am breaking down a Beseler 4x5 for parts which has a good motor if you are interested?
The smell from the resistrol could be due to lack of use and an accumulation of dust in the control,

Melvin J Bramley said:

I am breaking down a Beseler 4x5 for parts which has a good motor if you are interested?
The smell from the resistrol could be due to lack of use and an accumulation of dust in the control,

Click to expand...

I will get back to you on this, I'm still making plans to convert a room into a ghetto darkroom, likely through the power of blackout blinds, or taping black plastic from floor to ceiling. I wouldn't consider buying new parts till I have it in final location, in case I eff something up moving it from my university to my apartment.
Alternatively, and this is actually rather likely, I will exclusively use it at night and go with the cheapest "blackout" curtains and a few rolls of tape.

mshchem said:

The Resistrol is a simple dimmer switch, Beseler got rid of this in the 70's. No grounded plug means 1950's , the enlarger should be grounded. Very simple to do if you have the proper cord, strain relief (parts) and know how.
You can run a small extension cord directly to the 2 prong lamp plug and then plug this into your timer (if you have a timer)

Sometimes when transporting the enlarger can get out of sync and the motor will labor to move it up and down.

I would use the Resistrol on full power, or eliminate it entirely.

Click to expand...

my interest in the Resistrol is simply to save bulb costs long term, and I'd be interested in trying to use it to equalize brightness between contrast filter grades for split toning. I have made a basic key using an ilford exposure meter that was part of the lot of things I ended up with. I'd like to ground the motor housing as well, I guess it does make more sense to just wire in a grounding prong and attach directly to the case units?

f/Alex said:

my interest in the Resistrol is simply to save bulb costs long term, and I'd be interested in trying to use it to equalize brightness between contrast filter grades for split toning. I have made a basic key using an ilford exposure meter that was part of the lot of things I ended up with. I'd like to ground the motor housing as well, I guess it does make more sense to just wire in a grounding prong and attach directly to the case units?

Click to expand...

Proper ground means that the entire chassis should be grounded with a 3 prong polarized plug.

Of course in my youth I remember just running a 12 AWG solid copper wire from the chassis of an old Maytag wringer washing machine to a iron water pipe with a ground clamp. This was when all the water pipes were metal.

A better idea would be to ground to a metal electrical box or conduit.

Check to make sure the carriage as not jumped a tooth on one side, thus making the motor work harder. If it has, search here and over on Photrio for instructions on how to rectify the situation. The process is fairly simple, but the tensioning spring inside the crossbar needs to be handled with care first.

If the gearing seems good, check that tensioning spring. Often, they end up slack (someone has de-tensioned it inadvertently) and it needs re-tensioning. The motor won't lift the carriage by itself, it need the spring assist (just like a garage-door opener).

New motors or a repair or replacement might be a viable option.

Ditch the Resistrol altogether. The dimming function just makes working with VC papers more difficult because it changes the spectrum of the light source, shifting it to red and away from blue as you dim. Just run the bulb through a dedicated timer circuit (do check voltages first).

Best,

Doremus

Doremus Scudder said:

Check to make sure the carriage as not jumped a tooth on one side, thus making the motor work harder. If it has, search here and over on Photrio for instructions on how to rectify the situation. The process is fairly simple, but the tensioning spring inside the crossbar needs to be handled with care first.

If the gearing seems good, check that tensioning spring. Often, they end up slack (someone has de-tensioned it inadvertently) and it needs re-tensioning. The motor won't lift the carriage by itself, it need the spring assist (just like a garage-door opener).

New motors or a repair or replacement might be a viable option.

Ditch the Resistrol altogether. The dimming function just makes working with VC papers more difficult because it changes the spectrum of the light source, shifting it to red and away from blue as you dim. Just run the bulb through a dedicated timer circuit (do check voltages first).

Best,

Doremus

Click to expand...

+1

see PM.

If the motor is unable to lift the head, and runs very fast when lowering the head, then the tensioning spring was probably de-tensioned, as @Doremus Scudder suggested.

Mark

albada said:

If the motor is unable to lift the head, and runs very fast when lowering the head, then the tensioning spring was probably de-tensioned, as @Doremus Scudder suggested.

Mark

Click to expand...

I believe this may be the issue, it lifts the head to about halfway till the stop, but then is unable to lift it any farther. *just about* underneath where it'd need to be to make 8x10 sized prints from 4x5 negs, which is a lot of what I do rather often.

Alex,

Do take time to search for instructions about tensioning the counterbalance spring. It's not rocket science, but there's a lot of force in a tensioned spring that you don't want released inadvertently. Maybe someone with recent experience will chime in here. I haven't dealt with one for years; I'd have to look it up too.

Best,

Doremus