Beseler 45MXT issues

I have an elderly Beseler 45MXT that has a sticky focus issue.
Possibly part of the issue is the plastic guides on the focus rack which when tightened to point where there is no movement leads to a click click as the focus is adjusted and focus is missed be it going up or down the rack.
Do the plastic guides/ slide bearings need to be replaced?

The other issue is the so called focus locking cartridge .
The Beseler parts breakdown offers no detail on what the part consists of.
My enlarger has knob and an all metal plunger that grabs , or doesn't, the focus shaft.
This seems primitive ; I expected a friction spring or nylon plunger; just what should be in the part?

Any help please.?

Should I dump it and fin an LPL 4500 ?

TB

Melvin J Bramley said:

I have an elderly Beseler 45MXT that has a sticky focus issue.
Possibly part of the issue is the plastic guides on the focus rack which when tightened to point where there is no movement leads to a click click as the focus is adjusted and focus is missed be it going up or down the rack.
Do the plastic guides/ slide bearings need to be replaced?

The other issue is the so called focus locking cartridge .
The Beseler parts breakdown offers no detail on what the part consists of.
My enlarger has knob and an all metal plunger that grabs , or doesn't, the focus shaft.
This seems primitive ; I expected a friction spring or nylon plunger; just what should be in the part?

Any help please.?

Should I dump it and fin an LPL 4500 ?

TB

Click to expand...

Could need a tiny bit of lubrication. I would rub a couple milligrams of Vaseline on the aluminum parts. Tiny bit.

I guess I have an even older Beseler 45MX; I don't have any focus cartridge. The focus rack on mine runs up/down a toothed rack mounted on a wide(ish) length of aluminum. The plastic guides run up/down the edge of this piece. I have found the adjustment of these guides to be quite tricky. Just a tad (and I mean a darn little tad) to tight and it's difficult to achieve focus because the mechanism jerks. Just a tad to loose and the weight of the lens stage will pull down from gravity. It usually takes me about a half hour to get it just right. I loosen the lock nuts, turn the screw just a wee bit, tighten the lock nut, and try it. In 40+ years of using this enlarge, I've never applied any lubrication to the focus mechanism.

mshchem said:

Could need a tiny bit of lubrication. I would rub a couple milligrams of Vaseline on the aluminum parts. Tiny bit.

Click to expand...

The owner's manual specifies Lubriplate.

M Carter said:

The owner's manual specifies Lubriplate.

Click to expand...

Yes, I think that is a white lithium grease. Slippery stuff. It doesn't take much. I've experienced the focus bellows jumping a bit. I sold my oldest Beseler 45 I now have 3 setup, newer no problems. These are nice enlargers, not without little quirks.

Biggest issue are dichro colorheads. All of the older versions are problematic. I have spares and can make minor repairs. The only fool proof lamp house is the original condenser head with a 211 or 212 bulb.

I bought my first Beseler 45 50 years ago next summer.

mshchem said:

Yes, I think that is a white lithium grease. Slippery stuff. It doesn't take much. I've experienced the focus bellows jumping a bit. I sold my oldest Beseler 45 I now have 3 setup, newer no problems. These are nice enlargers, not without little quirks.

Biggest issue are dichro colorheads. All of the older versions are problematic. I have spares and can make minor repairs. The only fool proof lamp house is the original condenser head with a 211 or 212 bulb.

I bought my first Beseler 45 50 years ago next summer.

Click to expand...

Has anyone pic's of the 'locking cartridge' on the focus rack?
Mine may be a home made replacement.

Melvin J Bramley said:

Has anyone pic's of the 'locking cartridge' on the focus rack?
Mine may be a home made replacement.

Click to expand...

Here's what mine looks like; Beseler 45MX bought new in 1979.

Melvin J Bramley said:

Has anyone pic's of the 'locking cartridge' on the focus rack?
Mine may be a home made replacement.

Click to expand...

Here's my 45MCX. It's identical to that of @Alan9940. The small knob in the center locks the focus.

What is behind the small knob?

Melvin J Bramley said:

What is behind the small knob?

Click to expand...

The knob is just a screw that locks the focus in place. So to focus, you loosen the knob adjust focus, then re tighten the knob to hold the focus in place.

I’d first spray it all with electrical contact cleaner. Getting it clean often solves problems.

Melvin J Bramley said:

What is behind the small knob?

Click to expand...

I haven't disassembled it to be sure, but based on its position and behavior, I think there's a small block of metal which is behind the focus shaft. When you tighten the knob, you are pressing that block against the focus shaft, making it stiff.

mshchem said:

The knob is just a screw that locks the focus in place. So to focus, you loosen the knob adjust focus, then re tighten the knob to hold the focus in place.

Click to expand...

FWIW, I've never used that knob to lock focus. I adjust the tension on those plastic pieces until the lens stage moves smoothly, but stays put when the focus knob is released. Never had an issue with unsharp prints due to focus drift.

Link to Beseler parts


There's a knob and a spacer illustrated. This is to lock the lens stage in place. The diagram is for the current MXT model which has a modified lens stage to accept the 3 lens turrets. Wonderful things these turrets.

My mistake, I thought the lock cold be used to create friction on the focus rack, no such luck.
I am going to try and replace the Beseler cartridge with a brass washer and spring !

Thanks for the input.

I used one of my Beseler 4x5 enlargers today. Focus stays in place without locking, I always lock out of habit.

mshchem said:

Biggest issue are dichro colorheads. All of the older versions are problematic. I have spares and can make minor repairs. The only fool proof lamp house is the original condenser head with a 211 or 212 bulb.

Click to expand...

Yep, I'm using a 45MXT. It came with a Dichro head and I was so excited. I used it for a while (B&W only, but without needing to buy Ilford MG filters), and it pretty quickly became clear that the contrast was very different at any given setting than I expected. More importantly, it was doing the "random delay between hitting the start button and the lamp actually turning on) thing. I could have worked around that if it was consistent, but it varied unpredictably from instantaneous to about 2 seconds. Hugely problematic for short exposures, and to make it worse, I like to print stereo pairs where the exposure really does need to be exactly the same for both sides of the print or it's highly noticeable.

Ditched the dichro head and put the condenser back on. It's fine. Heavy, tall, and hot. And the more advanced I get in my silver gelatin work, the more I find myself switching back and forth between filters for various split-grade dodge/burn applications, which is a hassle. That's why I'm making a DIY LED-based diffusion head that will allow me to dial in green and blue light levels with high precision, and much more conveniently than shuffling 5" filters back and forth.

I replaced the Dichro head in my 45MXT with a homebrew LED pot light. I was using under the lens filters anyway. I got frustrated trying the keep the old beast working. I have never looked back and the lack of fan and vibration makes for a sharper image.

BHuij said:

Ditched the dichro head and put the condenser back on. It's fine. Heavy, tall, and hot. And the more advanced I get in my silver gelatin work, the more I find myself switching back and forth between filters for various split-grade dodge/burn applications, which is a hassle. That's why I'm making a DIY LED-based diffusion head that will allow me to dial in green and blue light levels with high precision, and much more conveniently than shuffling 5" filters back and forth.

Click to expand...

I replaced my condenser with a DIY LED-head. I copied Mal Paso's design described at this link. It works well, and is much more convenient than shuffling filters.
It's been 2-1/2 years since the posting linked above, and more modern components are available. Based on my experiences, I have these suggestions:

• The Mean Well NLDD series of drivers work well. The CALE series (made by Diwell) also look promising, but I haven't tried them.
• Run LEDs a half-stop or more below their rated maximum current, to improve their life.
• Run blue at half the current of red and green, because paper is more sensitive to blue.
• Use royal blue LEDs (450 nm) instead of normal blue (465-470 nm) so you can reach max contrast (grade 5) in B&W. For color, royal blue might not be best.
• Generate PWM using an Arduino or PIC18 or similar. A 555 will work, but accuracy can be poor.
• Use at least 12-bit PWM to give you sufficient accuracy a few stops below 100%. I can give you source-code for Arduino Uno or PIC18.
• Use Cree LEDs, as they have minimal spurious emission outside their specified spectral-curves. Luxeon might be good too, but I haven't tried them. I tried a cheap LED, and found it had wide splatter.
• Buy LEDs mounted on "stars" from ledsupply.com. But they are not yet offering the new Cree XE-G LEDs on stars, so I bought those LEDs from mouser or digikey and the stars from Cutter electronics in Australia, and soldered them myself. The existing XPE2 LEDs on stars offered by ledsupply.com work fine.

PM me if you need LEDs on stars or Mean Well drivers.

Thanks for the info - I'm well down the road and past the point of choosing and sourcing components already though. The LED array I have chosen has been independently tested by another guy, he's the one who recommended these ones to me as he did all the research on emission spectra. They're RGB Neopixels, and he found when he sets them to 100% green and 0% blue blend (not necessarily the brightest green, but a blend that has zero blue), his paper contrast range exactly matches Ilford MG grade 00 filters. When he sets them to 100% blue and 0% green blend, he exactly matches grade 5 in contrast range. Those tests were good enough news for me to pull the trigger on parts, but the kicker is when he had a 50%/50% mix of red and blue, the contrast range exactly matched Ilford Grade 2.

I tend to make smallish prints, and have had trouble getting exposure times short enough without resorting to diffraction-plagued f-stops on my enlarger lens with some of my negatives, so even without consideration for LED lifespan, I'm still planning on running them fairly dim. But if I'm ever making a large print, especially one from a small negative, I have the option of brightening things up just for that exposure.

I'm sure I'll have a fairly comprehensive post up when I get mine working and dialed in. But I am 3D printing the lamphouse as I type, and have completed about half of the coding for the custom-built control panel/f-stop timer already. Just waiting on custom PCBs to arrive from China and I should be ready to solder everything up and start running test strips to find which blends of blue and green light at which brightnesses can replicate the experience of using multigrade filters. Specifically I want to calibrate so that I can have a rotary encoder for "grade" that turns in 1/10th grade increments without changing Zone 8-9 highlight density, and then a second rotary encoder for "brightness" that I can do in stops. If it all works out, I could always select my grade and then simply tune brightness to get an optimal exposure time at the best f-stop on the lens for maximum sharpness.

BHuij said:

Thanks for the info - I'm well down the road and past the point of choosing and sourcing components already though. The LED array I have chosen has been independently tested by another guy, he's the one who recommended these ones to me as he did all the research on emission spectra. They're RGB Neopixels, and he found when he sets them to 100% green and 0% blue blend (not necessarily the brightest green, but a blend that has zero blue), his paper contrast range exactly matches Ilford MG grade 00 filters. When he sets them to 100% blue and 0% green blend, he exactly matches grade 5 in contrast range. Those tests were good enough news for me to pull the trigger on parts, but the kicker is when he had a 50%/50% mix of red and blue, the contrast range exactly matched Ilford Grade 2.

Click to expand...

Is this the NeoPixel part you will be using?: Link to 16x16 NeoPixel RGB Matrix
I looked up the specifications of the two kinds of LED parts they use, and blue in both are 470 nm. That will not quite reach grade 5. Did your friend determine grade by measuring steps from a calibrated Stouffer 0.1-step wedge with a densitometer, and interpolate between steps? Or are you using a NeoPixel matrix with a shorter blue wavelength than 470 nm?

Anyway, the blue-green ratios for the grades differ among types of paper. Do you plan to keep these grade-tables in the EEPROM of your controller? If you also keep intensity-data in EEPROM, then you could program the controller to make identical prints on any paper-type. That means you could create test strips and test prints on cheap paper, and make the final print on costly paper, saving money.

It's similar to that one but a slightly different spec. The guy who did all the testing used a Stouffer step wedge and densitometer to check density. I believe the contrast index for Grade 5 was within 0.01 units (don't recall the units he was using) of the grade 5 strip he made using actual Ilford filters. I don't think he had done the math yet to interpolate between steps, but that's kinda the idea - although I'm assuming it will not quite be a linear mathematical relationship. To be honest, even if I fall slightly short of a hard Grade 5, I'm not that worried about it. I have long since calibrated my preferred film stock/developer combos for Zone System use, and almost everything I have printed in the last few years has been at or very near Grade 2. I can think of exactly one negative where I ever used the Grade 5 filter. It was pretty severely underexposed, and I was going for an essentially black & white rendition with almost nothing by way of tonal gradation.

The MCU I'm using is a RP2040 on a Pico board, which itself is soldered onto a custom PCB so that all my buttons and knobs and the red LCD display can be wired in an efficient and compact manner. I'm using CircuitPython for all the coding, which I guess technically counts as "firmware" since it runs on bare metal. One of the advantages of this setup is that I can at any point simply plug a USB cable into the Pico and open up/edit the code on my Macbook. So yes, as I calibrate I'll be storing the values needed to match each filter/grade as hardcoded numbers inside python variables. For all intents and purposes here it's the same as EEPROM even though it's technically not.

At this point I'm so happy with my Ilford Multigrade FB Glossy that I'm not super interested in branching out to other papers. I used to stock RC paper to make contact sheets, but these days I usually just throw the negs in a print file on the light table and take an inverted phone picture to serve as a contact sheet. But if I ever did have more than 1 kind of paper, I suppose it would be easy enough to save different sets of RGB values to correspond to effective grades for different papers. I could program one of the rotary encoder buttons to switch paper "presets" on a long press or something like that.

I must say I do kind of like the idea of test strips on RC paper and final prints on FB paper, but the cost difference between the two is relatively negligible at this point, so I'll leave the math and testing time it would take to get there to people who are more worried about pinching pennies than I am

BHuij said:

Yep, I'm using a 45MXT. It came with a Dichro head and I was so excited. I used it for a while (B&W only, but without needing to buy Ilford MG filters), and it pretty quickly became clear that the contrast was very different at any given setting than I expected. More importantly, it was doing the "random delay between hitting the start button and the lamp actually turning on) thing. I could have worked around that if it was consistent, but it varied unpredictably from instantaneous to about 2 seconds. Hugely problematic for short exposures, and to make it worse, I like to print stereo pairs where the exposure really does need to be exactly the same for both sides of the print or it's highly noticeable.

Ditched the dichro head and put the condenser back on. It's fine. Heavy, tall, and hot. And the more advanced I get in my silver gelatin work, the more I find myself switching back and forth between filters for various split-grade dodge/burn applications, which is a hassle. That's why I'm making a DIY LED-based diffusion head that will allow me to dial in green and blue light levels with high precision, and much more conveniently than shuffling 5" filters back and forth.

Click to expand...

Good luck with your LED project. The delay problem is usually cured by replacing a single opto-isolator on the Beseler PCB. I've fixed 3 or 4 heads this way.
LED is a great solution.

BHuij said:

It's similar to that one but a slightly different spec.

Click to expand...

Could you post what it is (brand, model, link)? I'm curious because I like to know what's out there that's suitable for enlargers, and there are probably others who would benefit as well.

BHuij said:

The MCU I'm using is a RP2040 on a Pico board, which itself is soldered onto a custom PCB so that all my buttons and knobs and the red LCD display can be wired in an efficient and compact manner. I'm using CircuitPython

Click to expand...

Did you mean MicroPython?
Your posting above made me spend an hour or two looking into the Pico. I had not considered using a Raspberry Pi because I thought it ran Linux which would take 30 seconds or more to boot. Here's what I discovered about the Pico:

• It boots in about 1/8th of a second.
• It has eight 16-bit PWMs (needed for accurate PWM several stops down).
• It has a 12 MHz crystal on-board (needed for accurate timing).
• It can accept a standard male header (needed for attaching to a perf-board).
• It has plenty of GPIOs for buttons, display, etc.
• It has plenty of flash and RAM.
• It's cheap.

Wow -- that checks all the boxes. I think my next project will use the Pico.

CircuitPython is a specific fork of MicroPython that’s aimed at being maximally convenient and beginner-friendly. I am a beginner and found it to be both of those things haha.

The “normal” line of Raspberry Pi generally has Linux installed, they’re full blown computers. The Pico is more aimed at driving simple hardware, it’s much more in line with something like an Arduino. I agree that it was the ideal chip for this project. Love how cheap they are too. And the RP2040 is a surprisingly capable little processor for the size and price.

I got mine, soldered on the headers, and just threw all my input devices and the Pico onto a breadboard and wired it up so I could start writing code.