Omega Enlarger problem

Matt Brown · Jul 9, 2011

Hi All,

So I've nearly gotten my swank new darkroom set up, and everything is going smoothly save for one hitch...every time I plug in my Super Chromega D Dichroic II enlarger it trips the ground switch on the socket. I've tried running it through the standard power supply via multiple different timers, and through the Chromegatrol timer/power supply.

My line is from a 15-amp circuit and I'm running 110V. From what I've read and can tell, the power supply and the Chromegatrol should be able to run on this. There is a "tap" line in the Standard power supply that I can change to 100V, 110V and 117V. I've tried them all and nothing seems to work.

I've tested the socket and the power supply with a Voltage/Ohm meter and they seem to be in perfect working order. It's only when I plug in the enlarger that I lose power.

Sooo...does anyone know where I should start with the enlarger? Is there a connection or piece of wiring that goes bad, typically, in these Omegas?

I'm not an electrician, and I've never taken apart an enlarger, but I may have the assistance of a friend who is more technically-inclined...

Any help would be much appreciated...

-Matt

jeffreyg · Jul 9, 2011

Have you tried plugging it into a different socket? Perhaps with an extension cord into another room. There may be other things running on that circuit that you are unaware of.

http://www.jeffreyglasser.com/

George Nova Scotia · Jul 9, 2011

Are you referring to a GFI type outlet? The breaker on a Ground Fault Interrupter pops when there is current flow or leakage to ground. This would possibly indicate a wiring fault in the enlarger.

Rick A · Jul 9, 2011

There is the possibility of a short in the wiring somewhere in the enlarger. Also check to make sure it's grounded properly. If you are plugging into a ground fault interrupter recepticle and it trips immediatly, could be a bad ground on the machine.

Ian C · Jul 9, 2011

This is not common to the Omega Dichro II power supply or the Chromegatrol.

About your comment,

every time I plug in my Super Chromega D Dichroic II enlarger it trips the ground switch on the socket.

I presume that you mean that the circuit breaker in you building opens.

If so, theres obviously a short circuit when the power supply is connected to the outlet, or as others have pointed out, a ground defect if you circuit is equipped with a GFI.

The Omega D Dichro II power supply or the Chromegatrol (power supply + voltage stabilizer + timer) both contain a 120v to 22.5v step-down transformer for the lamp circuit.

Make sure that the cord and plug dont have any cuts that could short the conducting wire. I presume that youve already satisfied yourself that the outlet is not the cause.

If it shorts with both the standard power supply and the Chromegatrol, then theyre unliky to be the source of the short. The short is likely somewhere from the 6-blade connector that plugs into the back of the power supply or Chromegatrol on the end of the cable bundle to the head, inside the cable bundle (unlikely unless the bundle is kinked or cut), or somewhere inside the head.

The fan and the panel illuminator lamp operate on 120v. That circuit seems the most likely candidate for the short circuit.

brucemuir · Jul 9, 2011

I recently rebuilt a Super Chromega Dichroic II to mount on my older DII chassis.

First place I'd look is the enlarger bulb socket.
These are super easy to replace and readily available for cheap and most are deteriorating if they sit unused for some time.

It looks like a squareish porcelain socket. The bulb plugs into this socket via pins and the pins can shear easily.

George Nova Scotia · Jul 9, 2011

If it is a GFI outlet it won't take much to make it pop. Could just be corrosion bridging some contacts.

Bob-D659 · Jul 9, 2011

No corrosion needed, just some damp dust between hot and ground on a terminal strip will trip a GFI. It's also possible your GFI outlet needs to be replaced, they can get overly sensitive with age.

Matt Brown · Jul 9, 2011

Thanks Jeff,

Yes, I did try it on a different socket in another room. Same problem. I even turned off all of the electrical devices on my circuit and the same thing happened.

Matt Brown · Jul 9, 2011

Ian C said:
This is not common to the Omega Dichro II power supply or the Chromegatrol.

About your comment,

every time I plug in my Super Chromega D Dichroic II enlarger it trips the ground switch on the socket.

I presume that you mean that the circuit breaker in you building opens.

If so, theres obviously a short circuit when the power supply is connected to the outlet, or as others have pointed out, a ground defect if you circuit is equipped with a GFI.

The Omega D Dichro II power supply or the Chromegatrol (power supply + voltage stabilizer + timer) both contain a 120v to 22.5v step-down transformer for the lamp circuit.

Make sure that the cord and plug dont have any cuts that could short the conducting wire. I presume that youve already satisfied yourself that the outlet is not the cause.

If it shorts with both the standard power supply and the Chromegatrol, then theyre unliky to be the source of the short. The short is likely somewhere from the 6-blade connector that plugs into the back of the power supply or Chromegatrol on the end of the cable bundle to the head, inside the cable bundle (unlikely unless the bundle is kinked or cut), or somewhere inside the head.

The fan and the panel illuminator lamp operate on 120v. That circuit seems the most likely candidate for the short circuit.

Thanks very much, Ian. The first thing I do will be to look at the 6-prong connector. I very much appreciate it.

Matt Brown · Jul 9, 2011

brucemuir said:
I recently rebuilt a Super Chromega Dichroic II to mount on my older DII chassis.

First place I'd look is the enlarger bulb socket.
These are super easy to replace and readily available for cheap and most are deteriorating if they sit unused for some time.

It looks like a squareish porcelain socket. The bulb plugs into this socket via pins and the pins can shear easily.

I've read in other forums that the ceramic piece can be a problem. I'll check that as well. Thanks!

brucemuir · Jul 9, 2011

Matt Brown said:
I've read in other forums that the ceramic piece can be a problem. I'll check that as well. Thanks!

I should mention that although the bulb socket in mine was corroded and turning to dust, it wasn't tripping any breakers.
The lamp just wouldn't light obviously.

There is also a separate socket inside to light the CMY numbers from the rear. This one is the same type used for running lights on older US cars.

Sirius Glass · Jul 9, 2011

Start with the power supply. Open the case and first look for any bare wires; especially bare wires close to the case. Vacuum out any dust and wipe dirt off any surfaces that you can get to. Replace bare wires or splice in better insulated wire. Clean out any corrosion. Clean all terminals and sockets. Others can suggest additional things to look for. I have not worked with electronics for a long time.

After the power supply, look at the enlarger head.

Then do the same with any item that causes the problem when attached.

Steve

tkamiya · Jul 9, 2011

Matt Brown said:
every time I plug in my Super Chromega D Dichroic II enlarger it trips the ground switch on the socket.

I'm not an electrician

I am. It makes a HUGE difference what the problem might be depending on whether you are talking about a circuit breaker or GFI (Ground Fault Interrupter). Please make it clear which is tripping, a circuit breaker or a GFI.

Matt Brown · Jul 9, 2011

tkamiya said:
I am. It makes a HUGE difference what the problem might be depending on whether you are talking about a circuit breaker or GFI (Ground Fault Interrupter). Please make it clear which is tripping, a circuit breaker or a GFI.

It's the GFI. I didn't know the difference until last night. But it's definitely the GFI.

tkamiya · Jul 9, 2011

Is your GFI part of an electrical panel and looks like any regular circuit breaker but with a "test" button or is it a type that looks more like a socket (except it has a test button) and installed on a wall?

You said you tried different socket in the house and it all did the same thing. Were all other circuit breakers GFI type also or did non-GFI type tripped as well?

Is your plug 3 prong type or 2 prong type? (in other words, is there a round ground pin?)

Matt Brown · Jul 9, 2011

tkamiya said:
Is your GFI part of an electrical panel and looks like any regular circuit breaker but with a "test" button or is it a type that looks more like a socket (except it has a test button) and installed on a wall?

You said you tried different socket in the house and it all did the same thing. Were all other circuit breakers GFI type also or did non-GFI type tripped as well?

Is your plug 3 prong type or 2 prong type? (in other words, is there a round ground pin?)

It's a socket GFI installed in a wall. I tested it on 4 different outlets, on 2 different circuits. All of the outlets were GFI-installed. The plug is a 3-prong type.

tkamiya · Jul 9, 2011

Here's something strange. Not all wall outlets in a typical home isn't GFI protected. Typically, kitchen, bathroom, and garage outlets are protected, but no where else. So please re-check your findings.

Assuming it IS really tripping the GFI that is installed on the wall and looks like an outlet...

What that means is, you likely have some "leakage" somewhere in your enlarger. You have two wires in A/C outlet. One is the supply line (black) and the other is the return line (white). All of the current from supply should return to return. Well, in your case, it doesn't.... some of it leaks to the chassis and your GFI breaker is sensing this. If it weren't for the 3 prong plug where one is ground, you may even feel a shock when you touch metal portion of your enlarger.

You are dealing with fairly old unit. Your transformer could have lost insulation. Some rodent could have chewed on wires. Maybe there's heavy dust on something which in turn got wet creating a pass for electrical power to leak.

As to what you can do, really depends on your skill level. What I suggest you do is to unplug from the wall. Let it sit for 30 minutes or so to let any charges bleed through. Then start your visual inspection. Start from your plug. Then the wire, all the way to the chassis. Any cracks, loss of insulation, etc, should be noted and repaired. Then, carefully open the cabinet and see if you see heavy accumulation of dust, loss of insulation, or any damage that are visible. Old transformers can leak and that damage may or may not be visible as it is an internal damage in the windings and insulation. If there is a plug, note which direction it plugs in and unplug it, then clean, then plug it back in. Do this one at a time.

Since you have no electrical experience, we are strictly looking for damages that you can see.

If you plug this into an outlet without a GFI, it will probably do something but I DO NOT RECOMMEND THIS. If the damage is substantial, you may be risking your safety. If you should do this CAREFULLY JUST TO TEST, and you find regular circuit breaker trips too, then you have a dead short somewhere and that's a whole different problem.

I'm going to stop here and see what you can find. Please make sure it is unplugged before you attempt any of this, and proceed slowly and carefully. Take notes on how you disassembled and unplugged anything.

Matt Brown · Jul 11, 2011

tkamiya said:
Here's something strange. Not all wall outlets in a typical home isn't GFI protected. Typically, kitchen, bathroom, and garage outlets are protected, but no where else. So please re-check your findings.

I've actually got the enlarger in a studio, where all of the outlets were wired with a GFI switch. It was like that when I got the place.

I will definitely do as you suggested and go over the enlarger with a fine-toothed comb. I'll message back here what I find in the next couple of days. Thanks!

Robert Hale · Jul 11, 2011

Hi Matt

Only just dropped in on this query of yours. First simple test, the Chromegatrol will run without the six bladed head plug in it's socket, try this and if this does not trip the switch then your problem is in the head. if the switch is tripped then it's in the Chromegatrol setup. If it's the head get a professional to check the wiring as it does some loop back type stuff.

If it's in the control/transformer then google "ask harry" and follow his advice.

Regards

Rob

ic-racer · Jul 12, 2011

So both the Chromegatrol and the standard power supply trip the GFI but not the circuit breaker, right? Do the two power supplies trip the GFI when the enlarger head is unplugged from the power supply?

Matt Brown · Jul 14, 2011

ic-racer said:
So both the Chromegatrol and the standard power supply trip the GFI but not the circuit breaker, right? Do the two power supplies trip the GFI when the enlarger head is unplugged from the power supply?

Nope, they have to be plugged into the enlarger for the GFI trip to occur.

ic-racer · Jul 15, 2011

Matt Brown said:
Nope, they have to be plugged into the enlarger for the GFI trip to occur.

Ok. There is not much in the head to go wrong. Perhaps the fan is bad.

tkamiya · Jul 15, 2011

Are you able to inspect the connector, inside the connector, and the wire itself? Insulation can go bad.

John Weinland · Jul 18, 2011

I have that Omega too, and there may be something intrinsic to the Omega timer that could trip a GFI. Looking at the schematic, you can see that there is a voltage-buck/boost winding on the power transformer with a series capacitor that will charge and discharge along with the inductive buck/boost winding. (It's the winding that does not appear to be connected to anything else). The initial power-on surge-backsurge through that buck/boost winding could appear to the GFI like a partial short between the neutral and hot line-input wires. Try the enlarger with all its accessories on an outlet that is not GFI-protected. If it works flawlessly, without any apparent electrical problems, the Omega may 1) either not be compatible with GFI outlets or 2) you have a very sensitive (low-current-trip) GFI. An electrician may be able to help with GFI outlets with reduced trip-sensitivity. Good luck - and you may want to obtain a schematic diagram for troubleshooting.

Omega Enlarger problem

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