Beseler 45S taking 1-3 seconds to come on

Discussion in 'Darkroom Equipment' started by Skorzen, Oct 20, 2008.

  1. Skorzen

    Skorzen Member

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    I recently picked up a 45S head from the infamous bay for a very good price (as is, "didn't light up" as the lamp was missing). Well I put a lamp in it and it fired up just fine, except that it is not coming on instantly. It takes between 1 and 3 seconds for the light to come on. Any idea what might be causing this?

    It needs to be cleaned, there is a LOT of dust in the fan etc, I was only home from school for about a week so I didn't have a chance to dig into it as much as I would have liked. I suspect that the problem is somewhere in the power supply/switching part of the electronics. Has anyone dug into these and know how the power supply is set up?

    I hear what sounds like a solenoid being activated when power is supplied to the "timer" cord. I wonder if there is a solenoid is it possible that it is dirty and therefore not making contact as quicly as it should be?

    My other thought is that I believe there is some kind of voltage stabilization built in and perhaps it is taking time for whatever buffering circuitry there is in there to be charged and hence the delay in the lamp coming on.

    If anyone has seen this issue or know a little about what is under the hood in these heads (or just feels like ) would share whatever input they have I would be very appreciative. I am back at school, and don't have the head here, but I am trying to get a feel for what it needs so when I am home again I can dig into it in an informed fashion.
     
  2. TheFlyingCamera

    TheFlyingCamera Membership Council Council

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    I have a similar issue- it appears to improve when the enlarger is warmed up, but it still occurs, and is inconsistent in its duration and frequency. If you or anyone else has an insight into solving this problem, I'm all ears, as it is quite frustrating to have a good enlarger hooked to a very expensive timer and not get the full benefit of the timer because the light source is inconsistent.
     
  3. Photo Engineer

    Photo Engineer Subscriber

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    This has been reported before here and on other sites. It is a known problem with the Beseler heads in general and they were reported to have a fix for the electronics. I don't think it is something you can do yourself, but I have been able to improve it by cleaning the internal contacts and as noted, allowing it to warm up by firing it a few times before use.

    Mine is quite reliable if I clean it and allow it to warm up and do a few prefires.

    PE
     
  4. Bob-D659

    Bob-D659 Member

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    These are general troubleshooting notes, I have no knowledge of the Beseler color heads.

    Check all the wiring and crimp on connectors very carefully, also the bulb socket. If the copper wire in the crimp connectors is a brassy yellowish colour, there is a poor connection there and the wire is/was overheating. You will probably have to replace that piece of wire and the connector ends as it is rather difficult to remove the surface oxidation on the stranded wire to crimp or solder on a new connector.

    High wattage halogen bulbs are almost a dead short until the filament warms up and the resistance rises to limit the current draw. Any poor connection in the circuit from the transformer to the bulb will limit the inrush current and extend the startup time of the bulb. This is also one of the causes of burnt power transformers. Burnt high current relay contacts between the transformer and the bulb will cause problems as well.

    Clean the fan and oil the bearings. If there is an airflow sensor, that could delay the bulb start until the airflow is up to speed.

    If there is an open frame relay, check for surface corrosion, darkrooms are rather hostile environments for electronics, if the contacts appear burnt, either polish them or replace the relay.

    It doesn't take much to mess up a high current low voltage power feed to a 24 volt halogen bulb. Make sure any push on wire connectors are clean and tight. You can clean the blade terminals with a pencil eraser or a can of electronic contact cleaner and use a pair of pliers to slightly squeeze the push on fitting so it is a tight fit on the blade end.

    Best of luck.

    I'm not going to get into troubleshooting electronic control circuits, because if you know how, you probably would have been in there already. :smile:
     
  5. Nicholas Lindan

    Nicholas Lindan Advertiser Advertiser

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    This problem is usually traced to loose connections or a worn-out lamp holder. The holder for these lamps doesn't last long and is a replacement item along with the lamp.

    Blown voltage regulators are more common in heads that use the 82V halogen bulbs. If the problem is in the regulator, the problem is most likely due to a dried out electrolytic condenser; often wholesale replacement of all the electrolytic condensers will cure the problem with no need for troubleshooting. Early 90's electronics are notoriously prone to this problem.
     
  6. Roscoe

    Roscoe Member

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  7. Photo Engineer

    Photo Engineer Subscriber

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    The Dichro S comes in 2 models. One uses plain dials for setting the balance and no indicators, the other has an LED display on the front for the balance, and the LEDs are lit by a light balancing meter. They are not the same. The computer driven unit has 3 or more circuit boards.

    PE
     
  8. Skorzen

    Skorzen Member

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    Thanks for the information, it looks like that discussion will be very helpful. As both of these heads use an 82 VAC lamp, is it a safe (or at least good) assumption that the 45S head is the same as the 23 head electronically?
     
  9. Skorzen

    Skorzen Member

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    well, I actually have one of each of the 45s models, both with their own issues. The one I was asking about here is the plain "analog" version. I have one of the digital ones as well, but the middle digit on on magenta readout isn't working (making setting the filters a little frustrating, I may work on that one as well when I get a chance).
     
  10. Photo Engineer

    Photo Engineer Subscriber

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    Skorzen;

    With the enlarger off and unplugged:

    Open the top of the head and loosen the screws holding the circuit boards in place. Loosen them slightly and then reseat them and reattach the screw and close the top. This "jiggle" will serve to clean the contacts on the board and the middle digit should relight. I have to do this about twice a year on mine.

    PE
     
  11. Roscoe

    Roscoe Member

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    Earlier versions of the 45 head, to my understanding and from research done on the web, were similar, and the DDS head, again, to my understanding, had the same problem with the now obsolete optoisolator. The Dual Dichro (not"S", for internally stabilized) wasn't so afflicted. This was the model with the seperate stabilized voltage supply. I came across a guy who was supposed to be able to fix the various incarnations of the 45 & 23 heads (including the much more complex later ones) but by the time I found him, I'd solved my problem by picking up a used DD head on that bay thing.

    BTW, the older head was two and a half stops faster than the DDS; same voltage and lamp wattage, different lamp.