BESELER 23c II exposure hiccup

[Al--Pacino]

I have a Beseler 23c ii plugged into a Gralab 450 timer.

Occasionally when I hit for exposure, the bulb comes in dim and then brightens up to its proper brightness.
You can see in my video the first exposure comes in correct, then the next two come in with the hiccup.

I've tried several bulbs, seems like it's something beyond my electrical knowledge.

Thoughts?

 

[Rick A]

You may have a bad contact somewhere down the line. It could be the timer switch not making good contact when you push the button. I have a GraLab 525 that used to give me issues from time to time. Occasionally when I pushed the start button it would come on for an instant then shut off, the contactor wouldn't stay closed. I pulled it apart and sprayed everything down with contact cleaner. No problems since.

 

[mshchem]

Is this a condenser head with an ordinary tungsten bulb?
Does this happen when you eliminate the timer?
Is this a dichroic head?

 

[koraks]

You may have a bad contact somewhere down the line. It could be the timer switch not making good contact when you push the button.

This, or corroded contacts in the bulb socket. I'd start with the bulb socket, actually.

Welcome aboard @Al--Pacino !

 

[Al--Pacino]

Is this a condenser head with an ordinary tungsten bulb?
Does this happen when you eliminate the timer?
Is this a dichroic head?

Hello everyone--

Dichronic head. Quartz bulb.

Regarding the above replies, I've since tried a new timer, and also tested just turning the lamp on/off. The hiccup is still occuring.

There isn't a massive power draw either, it's on a seperate circuit from everything else in the room, and the safelite does not dim when i turn on the focus light, or expose.
I imagine this has something to do with the transformer. Before I bring in someone who knows more than me, what can I possibly do on my end to learn more about this problem so I could potentially fix it?

I'll look into the contacts on the bulb tomorrow, but idk if that's the issue.
It's truly inconsistent in its hiccup, sometimes it's .3 of a second, sometimes it takes .2 to even get dim before getting bright...definitely something I can't account for when printing.

 

[Bill Burk]

Add a second to all your times and hold a card in front of the lens for a second

 

[mshchem]

I have zero experience with the 23c

I have had similar problems with the Beseler 45s dichroic heads.

On the 4x5 heads delays like you are seeing was due to an aging optoisolator on the circuit board. These little things have tiny things look like a little metal can.

I have replaced these and have cured the issue.

I have no idea what/how the 23c heads are configured.

Are you printing color negatives?

A nice new LED head and controller is nice but sort of expensive.

 

[koraks]

I imagine this has something to do with the transformer. Before I bring in someone who knows more than me, what can I possibly do on my end to learn more about this problem so I could potentially fix it?

As said above, start with the bulb socket. These often suffer from corroded contacts.

It's possible that there's a problem in e.g. a voltage control feedback loop/servo like @mshchem mentions, but start with the basic stuff first.

 

[Ian C]

We need to know EXACTLY WHICH color head you have.

Per post #5, it’s a dichroic-filtered color head, either a DGA, Dual Dichro, or Dual Dichro-S. We also learned that the problem persists with a different timer. So the problem is not caused by the timer.

The DGA and Dual Dichro use a 120-volt to 24-volt step-down transformer The standard power supply is simply a transformer. These rarely give trouble.

There is also a more complex Stabilized Power Supply (24-volts to the lamp) that incorporates a voltage stabilizer.

The Dual Dichro-S has a built-in half-wave diode-and-resistor power supply with built-in voltage stabilizer. It produces approximately 82 volts to the lamp.

Both the 24-volt Stabilized Power Supply and the 82-volt Dual Dichro-S power supply can become unstable as they age. This is most often traced to a component called an opto-isolator (trade name “Vacutrol”). There are several other electronic components in the voltage stabilizer that might have failed.

As mentioned by others, the lamp pins or the contacts in the lamp socket might have become corroded and cause the problem. The socket can be replaced. The socket is not a Beseler part and is available for a moderate price via Internet search.

One way to at least temporarily “fix” the problem of a corroded socket is to install and remove a lamp 10-12 times in succession to lightly abrade any corrosion from the pins or socket contacts. This might restore normal conductivity, at least temporarily, until you can secure and install a new socket.

In my case, my Dual Dichro Stabilized Power Supply kept burning out new lamps within a few seconds of powering the lamp. I measured pulsing voltage spikes at the lamp contacts as high as 60 volts. My solution was to replace the stabilized power supply with a standard power supply. It now works reliably, no more burned-out lamps seconds after installing.

For accurate color work with the standard power supply, you can install a voltage stabilizer between the wall outlet and the power supply.

If you have either of the two voltage-stabilized versions discussed above, there is a good chance that it is the source of the problem.

 

[Al--Pacino]

We need to know EXACTLY WHICH color head you have.


As mentioned by others, the lamp or the contacts in the lamp socket might have become corroded and cause the problem. The socket can be replaced. The socket is not a Beseler part and is available for a moderate price via Internet search.

I have a Duel Dichro-S.
I don't print color.
I will look at the contact points at the lamp today and give it a cleaning regardless. I'll report back after and give y'all an update.

 

[koraks]

I will look at the contact points at the lamp

You can't, really. The contacts form clamps that the lamp pins slot into; you can't generally visually inspect the actual contact surfaces. What does work is do as @Ian C suggests above and try to break through any layer of corrosion and see if that (temporarily) makes a difference. If so, this is a good indicator that replacement of the socket is a good idea. Which, depending on the price of a new socket, may be a good idea in any case.

 

[Ian C]

EVW lamp for Beseler Dual Dichro-S dichroic lamp head.

https://www.bhphotovideo.com/c/product/689614-REG/Impact_EVW_EVW_Lamp_250W.html

https://www.bhphotovideo.com/c/product/808876-REG/Ushio_1000386_EVW_Lamp_250W_82V.html

https://www.bhphotovideo.com/c/product/839830-REG/Sylvania_54723_EVW_250W_82V_Lamp.html


The lamp pins and socket are GY5.3 standard.

Socket and lamp holder/ejector assembly for EVW lamp.

https://www.1000bulbs.com/product/5...MIy-TqhtfKiwMVhlJ_AB32CjRqEAQYAiABEgKhDPD_BwE

EVW socket only

https://www.bulbamerica.com/product...MIy-TqhtfKiwMVhlJ_AB32CjRqEAQYAyABEgIYRvD_BwE

 

[Al--Pacino]

You can't, really. The contacts form clamps that the lamp pins slot into; you can't generally visually inspect the actual contact surfaces. What does work is do as @Ian C suggests above and try to break through any layer of corrosion and see if that (temporarily) makes a difference. If so, this is a good indicator that replacement of the socket is a good idea. Which, depending on the price of a new socket, may be a good idea in any case.

Afternoon!
I did as suggested and rubbed the contacts of the socket with a dead bulb I had lying around. No change.

Head info:
105-130v 60Hz
275 Watts Max Lamp 250

Attaching a picture of the lamp compartment in case any of you find it helpful.

 

[Chan Tran]

Isn't there a power supply sitting outside of the enlarger? (it's been so long I don't remember). It could be something wrong with the power supply because the bulb is 82V and can't be connected directly to wall outlet.

 

[Al--Pacino]

Isn't there a power supply sitting outside of the enlarger? (it's been so long I don't remember). It could be something wrong with the power supply because the bulb is 82V and can't be connected directly to wall outlet.

Depends on the timer. I have one with an internal supply, and one with an external (116v 60hz Output / 300w). I am experiencing the same issue regardless.

 

[koraks]

OK, thanks for checking the bulb socket; too bad it didn't help.

Depends on the timer.

@Chan Tran is asking about the power supply of the enlarger, I'm quite sure. That's the first place to look at, now. See also @Ian C's comments about the long-term stability of the 82V stabilized supply and the possible vacutrol/opto-isolator failure mentioned by @mshchem and @Ian C. I'd personally start by monitoring the 82V output of the power supply while cycling the bulb.

 

[Al--Pacino]

OK, thanks for checking the bulb socket; too bad it didn't help.



@Chan Tran is asking about the power supply of the enlarger, I'm quite sure. That's the first place to look at, now. See also @Ian C's comments about the long-term stability of the 82V stabilized supply and the possible vacutrol/opto-isolator failure mentioned by @mshchem and @Ian C. I'd personally start by monitoring the 82V output of the power supply while cycling the bulb.

Copy that-- I have an ohmmeter here. Just unsure of where to put it on this thing, and I'm aware Beseler is weird about putting out wire diagrams.
Anyone have a video or pictures, or detailed info on where to clip?

 

[Chan Tran]

Copy that-- I have an ohmmeter here. Just unsure of where to put it on this thing, and I'm aware Beseler is weird about putting out wire diagrams.
Anyone have a video or pictures, or detailed info on where to clip?

There is a 6 pin connector that you plug the color head into the power supply. 2 of these pins would be the ones but I don't know which ones. May be you can use the ohmmeter to find out which pins connected to the lamp socket. You would have to remove the plug cover in order to clip the voltmeter to the pins to make measurement. There is no real opto isolator in the power supply but I think they used the Cds photo resistor for this purpose and the response of the Cds cell can be not as responsive as before.

 

[Al--Pacino]

There is a 6 pin connector that you plug the color head into the power supply. 2 of these pins would be the ones but I don't know which ones. May be you can use the ohmmeter to find out which pins connected to the lamp socket. You would have to remove the plug cover in order to clip the voltmeter to the pins to make measurement. There is no real opto isolator in the power supply but I think they used the Cds photo resistor for this purpose and the response of the Cds cell can be not as responsive as before.

Oh I see!
I actually do not have this and never have?

 

[koraks]

I actually do not have this and never have?

So could you perhaps just post some photos of what you do have?

 

[Al--Pacino]

So could you perhaps just post some photos of what you do have?

It's all mentioned as far as I'm concerned,
Beseler 23cii, Dichrome Duel-S head, Gralab 450 Timer.
Never had a standard or stabilized power supply, never needed it.

Attached is an image from a few months ago.

 

[koraks]

Never had a standard or stabilized power supply, never needed it.

OK, so your wall socket outputs 115V. The bulb in your enlarger runs on 82V. Where does the voltage get transformed in your setup?

 

[Al--Pacino]

OK, so your wall socket outputs 115V. The bulb in your enlarger runs on 82V. Where does the voltage get transformed in your setup?

Never said I was an electrician, never learned about it in art school either.

It's to be understood that one of these power supply is required, but is not sold with the unit?

 

[koraks]

Can you list the items between your wall socket and the actual bulb in the enlarger head, and post a photo of each of these items?

 

[mshchem]

I suspect it's internal to the head. Sounds like your head has two power cords, both designed to plug into 110V 60 Hz. One supplies power to the enlarger main power switch, when you switch the main switch the cooling fan comes on.

The other 110V cord plugs into the timer or any sort of manual switch that controls the lamp.

82V is an internal power supply.

Every 45S colorhead I've had has had a similar failure of a Vactrol opto-isolator. I've fixed 4 of these, I just did what a Beseler employee told me to do. The Vactrol looks like a little soup can, has 4 leads. I'm not a electronic type, just did as told.

This is where I would start.