Page 1 of 3 123 LastLast
Results 1 to 10 of 23

Thread: Beseler Dichro 45 no light

  1. #1

    Beseler Dichro 45 no light

    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?

  2. #2
    Jon Shiu's Avatar
    Join Date
    Nov 2003
    Location
    Mendocino, California
    Posts
    1,280

    Beseler Dichro 45 no light

    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

  3. #3

    Join Date
    Sep 2003
    Posts
    1,539

    Beseler Dichro 45 no light

    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.

  4. #4
    Beverly Hills, California
    Join Date
    Feb 2000
    Location
    Beverly Hills, CA
    Posts
    1,100

    Beseler Dichro 45 no light

    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.

  5. #5

    Join Date
    Jan 2001
    Posts
    128

    Beseler Dichro 45 no light

    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?

  6. #6

    Beseler Dichro 45 no light

    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.

  7. #7

    Beseler Dichro 45 no light

    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!!!

  8. #8

    Join Date
    Dec 2006
    Posts
    1

    Re: Beseler Dichro 45 no light

    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

  9. #9

    Thumbs up c jane,so how do I get the boards out?...shorthoodRe: Beseler Dichro 45 no light

    Quote Originally Posted by Calamity Jane View Post
    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!!!

  10. #10

    Join Date
    Dec 2014
    Location
    Iowa City, Iowa
    Posts
    1,054

    Re: c jane,so how do I get the boards out?...shorthoodRe: Beseler Dichro 45 no light

    If you have an older Beseler 45 S Dichro head, assuming the bulb is good. You could gave a bad optical isolator on the circuit board. Usually the problem starts with delays in the lamp starting late or intermittently. Everyone of these heads, I've had 3 had this problem. Many years ago Beseler changed the design to resolve this. The part is obsolete, so I had a tough time finding parts even 15+ years back. I would need to check the numbers, there's two spots on the board Iso 1 and 2 can't remember which. I have it recorded in my notebook. It looks like a little aluminum can with leads soldered to the board. Vactrol was maker. Let me know if you want more info.
    Best Regards Mike

Similar Threads

  1. Beseler 45MCRX & Aristo light
    By Carlos in forum Darkroom: Equipment
    Replies: 8
    Last Post: 6-May-2005, 17:36
  2. Beseler Dichro 45 Computerized Head Power cable
    By Kirk Keyes in forum Darkroom: Equipment
    Replies: 2
    Last Post: 10-Dec-2004, 17:14
  3. Old Beseler Dichro DG 4x5 Color Heads
    By neil poulsen in forum Darkroom: Equipment
    Replies: 2
    Last Post: 12-May-2002, 15:10
  4. Light circle not covering on Beseler 45M. Help
    By Douglas P. Theall in forum Darkroom: Equipment
    Replies: 5
    Last Post: 20-Feb-2001, 19:41
  5. Beseler Dichro dg-1 color head
    By Al Sapouckey in forum Darkroom: Equipment
    Replies: 2
    Last Post: 5-Nov-1998, 17:17

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •