I recently acquired an old Beseler Dichro 45 color 4x5 enlarger. It gets electricity when turned on (The fan comes on and the LED's light up on the front), but the main bulb won't come on even though it's good (I bought a new one to check it out). The contacts for the bulb are hot when tested on a meter, which is what is perplexing me. I have no manual for it and don't know where to go next. Any suggestions?
Apologies if this is too obvious, but did you check the bulb with the meter?
my black and white photos of the Mendocino Coast: www.jonshiu.com
If this is a screw in lamp then the following may apply:
Occasionaly on certain equipment the center prong of a lamp socket will lose it's spring tension. When this occurs the prong will fail to contact the center electrical contact of the lamp and even though the socket checks O.K. with a meter it will not light the lamp.
That is what I would check first.
I know my Ushio high watt overhead bulbs that I use in my school overhead projector have a high rate of being "Dead on Arrival".
I'll bet it's the bulb, even though it's new.
Beverly Hills, CA (albeit a 99%er)
I believe this unit has a lever underneath the bottom right side that lifts the filters out of the light path for focussing. If the filters aren't returned to the light path afterwards, the light will not come on. Is this perhaps the problem?
Could be the bulb, even though new, of course. But unfortunately there is a a component in the lamp control circuit which has been obsolete for quite a few years, and if this item "blows" then the lamp circuit is uncontrolled, and may give you too high a voltage, blowing lamps, or too low a voltage or no voltage at all.
The component is ISO-3 on the board nearest the end of the unit. It is an unusual type of opto isolator, using an incandescent lamp instead of an LED , and thus is guaranteed to fail sooner or later. The fact that a voltage can be read by a meter at the lamp socket means nothing, unless the lamp is inserted at the time. Otherwise there is enough "leakage" to activate the meter, but it is only microamps, and is misleading.
I believe that a company called Baytron claims to be able to repair ISO-3, but that is all I know. Good luck.
I am just about finished restoring 3 Dichro 45s - only have a metering problem left in one unit. One unit had the exact same problem.
The most common (and universal) problem with the Dichro 45 is corrosion of the board-edge connectors and headers. At the time when these units were made, connector technology had some bugs.
The proper fix is to clean all the connectors, which means removing the 3 circuit boards. (Mark all the cables to the power control board with the P number on the board so you get them back in the right places!) The male header pins on the motherboard will show black deposits on the side toward the daughterboards. This needs to be cleaned off with some VERY fine emery cloth or sandpaper - "contact cleaners" will NOT remove these deposits. For all of the female headers on the daughterboards, use acetone and small wooden toothpicks to scrub every single one of these puppies! Keep working the toothpick back and forth into the connector hole (across the contact spring). When it gets dirty, switch to a clean toothpick and keep going until 4 or 5 strokes leaves the toothpick coming out clean, then move to the next one. I did one Monday and it took 3 hours :-(
When all the connectors are clean, put it back together.
I'd wager $100 your problem will have disappeared!
I'd suggest you could take it to a TV/radio repairman if you don't feel confident doing this yourself but 90% or repairmen will not take the time to do it right - they will spray it and call it good.
You may be able to get away with unplugging and plugging in the control board and the processor board (these are the only two that effect the lamp) and that saves disconnecting the miriad of cables from the control board.
WHAT AM I DOING????!!!! If I give away all my secrets, I won't get any more cheap 45s 'cause people will be fixing them themselves!!!
An old thread but I'll give it a try. Jane you still out there? I'll likely contact Baytron, but I was wondering if you ever saw this problem: I bought a DATA Module and all I did was switch the chips like you were supposed to. It didn't work, so I switched it back. Now all I get is whacky single digit blinking and the enlarger light flashing. What the heck happened? ... Much appreciate your input. Thanks. Don
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