Beseler 45MCRX motor struggles when raising

[anachronous_imagery]

When raising the Beseler 45MCRX, the motor starts to struggle as it gets to about halfway - requires a push. It looked like it had been in a barn for a few years.

I cleaned it up, lubriplate on the geared rails, new motor belt, cleaned motor commutator bars, one brush is a bit shorter than the other, but length on both seems adequate. Rollers on carriage bars rotate with ease.
With the carriage out of the frame, when I turn the manual elevation control, it turns easier in one direction than the other. I opened the gearbox, cleaned out the old grease - gears look great - no nicks, metal shavings, etc. There are roll pins that aren't fully in - protrude just a little - not sure if that is normal or if they should be fully 'seated' - but I can't detect any slop in the mechanism.

Not sure what to check - just had time to fool with it to see if it could be improved.

[Gary Beasley]

The counterbalance spring may be showing its age. I dont know if its possible to retension it to provide more lift. Until you can find a solution give the carriage a little lift with your hand while raising it to avoid overstraining the motor.

[LabRat]

First, take a tape measure and measure the height from each side of neg stage to baseboard... They should be exactly the same... If not, the gear shaft on the carrage/column in rear can jump a gear tooth on one side and cause the head assy to drag badly, as well as badly misalign...

Check for this first...

Steve K

[Duolab123]

Alignment.

[Dugan]

I'm with Steve K on this.

[Doremus Scudder]

There is a tensioning spring located in one of the chrome crossbars. It can be tightened. However, it is tricky and I've never tried it. Make sure you read up on the proper procedure before attempting it, since I understand that it is easy to do it incorrectly and accidentally release the spring tension completely all at once, which can result in damage and/or injury. Someone will likely chime in here with the proper method.

FWIW, I've adapted a 5x7 Chromega head to one of my Beseler 45Ms, which makes the moving part quite a bit heavier than with my earlier cold-light head or the condenser head. I just help the motor out by lifting with my hand when raising the head, which seems to work just fine.

Do check whether the gears are aligned on the toothed rails first; this is a common problem with these enlargers and easy to remedy.

Best,

Doremus

[Bernard_L]

the gear shaft on the carrage/column in rear can jump a gear tooth on one side and cause the head assy to drag badly

+1

[Eric Woodbury]

I have an old 45MX (maybe other letters) that I bought used in about 1980. It seemed old then, but the motor is still strong. Makes me think that your carriage could be off or you missed a lube point in the motor. I wouldn't mess with the springs unless you are absolutely sure. If the head you have is extra heavy and it goes down better than up, add a counterbalance weight, pulley, rope, and gravity.

[Duolab123]

It's easy to get a tooth or two off especially if someone has had it apart. If all you have is the condenser head (which isn't super light) it should move up smooth. If you have the 1st generation Dichroic head with the hose and cooling blower, there's a spring assist mounted on the transformer that hooks to the top off the enlarger frame. This gives it a boost. These heads date to the 70's and were great heads.
If you have an antique, Beseler started with the MCRX, M motor, C color filter drawer under condensers, R Resistrol, X for, Extra something. These started out in the 1950's, one clue is if the cord set and plug in for the switch ARE NOT 3 PRONG, i.e. not grounded. You have a 60 to 70 year old enlarger. I'm 63, and after a hard days work I climb stairs pretty slow.
If it's a blue enlarger it was made during the hip, and groovy phase Beseler went through in the early 70's.
Most likely is tired and needs adjustment and a little help up the stairs. . If it has the arm to allow for horizontal projection. Well you mount it on rails and move it to and fro from a wall mounted easel. Fred Astaire did that with one of these enlargers in the 1957 movie Funny Face, great flick, Audrey Hepburn.

[Eric Woodbury]

I heard the 'X' in the part number was for the 'X' shape supports on the main chassis.