Ilford 500 Multigrade Head - Green dichroic filter bulb not working

[Dacheste]

I have been trying to figure out this strange light issue I have been experiencing on my Ilford 500H head on my Durst 138 Enlarger. The Enlarger and head was left sitting for about 6 months, after which I purchased it from a friend. The enlarger appeared to work for our test before the purchase, but since has had issues. The first time the bulbs blew, I was raising the enlarger while the focus light was one, and the power cable from the head to the power supply had slight strain put on it, which caused both bulbs to blow. I replaced both bulbs and the enlarger was then working again for approximately 3 prints. The bulb with the green dichroic filter blew, while the bulb under the blue dichroic filter was still in tact. I again replaced just the one blow bulb and this time was able to get through 24 contact sheet prints before the same bulb blew. I again replaced the bulb, and was able to print another 13 prints before the green dichroic bulb again blew.

Having posted to the forum and heard people's suggestions that perhaps the light chassis were corroded, I went ahead and replaced both halogen chassis. Today when I returned to the darkroom to reaffix the head with the new chassis, I placed two brand new halogens into the chassis and turned on the power supply to find that only the bulb in the blue dichroic filter chassis worked. Both bulb were in tact, and when I switched the bulbs to the opposing chassis, the same thing occurred where the bulb in the chassis with the blue dichoic filter lit while the bulb in the chassis with the green dichoic filter did not turn on.

I am completely perplexed. To add to this I have noticed that on the Power Supply for the Ilford 500H, the light in the power button has blown out in the past few weeks along the same timeline as these issues. I am wondering if there may be an issue with the power supply that is causing this strange problem.

Thanks,
Diana

[Leigh]

I doubt you'll get any answers different from those you got on APUG.

- Leigh

[William Whitaker]

It could be the power supply, but I'd be highly suspicious of the cable between the power supply and the head. Truth is, it could be both. But the logical place to start is to replace the head. (That's where the cable is permanently attached, right? And it plugs into the power supply? I don't have access to mine right now and haven't used it in years.) If the cable has an intermittent or, more likely, an internal short, it could make for all sorts of difficulties which may or may not manifest themselves as logical symptoms. If it were me, I'd try to find another head, known to be working and swap it out to see if that will resolve the problems. If not, then look at the power supply. I do realize that if you swap out both components, then you've replaced the whole system and that that is not cost effective. But what is the alternative? You can't take it to a small appliance repair shop. And there is no one to make house calls to fix it. Start big and then try to narrow it down to isolate the defective component. Worst case, you'll end up with an entirely replaced system, that works. And you'll have parts left over, which may or may not have some market value as a box of parts.

Grim, but that's the cost of using old unsupported technology. The Ilford 500 is a great system. It's unfortunate that the market will no longer support it. Best of luck!

[brighamr]

Hi Diana

when you say that only one bulb comes on is
that not because that is how the system works
grades zero to three use the blue light and grades four to five the green light ?
I may of got that the wrong way around but i'm pretty sure from memory that there are never both bulbs on at the same time
when I last used an ilford 500 it was controlled from a RH designs controller and that's how it worked
it would focus using only one lamp and then would light one lamp and then the other depending on the grade

what is the voltage where you are ?
if the mains neon on the power supply has blown then maybe it is to high for the unit you have
there is a mains voltage switch on the back of the power supply

are you using the ilford controller or another one ?
the ilford controller had a switch on the back to balance the output of the green bulb to the blue one
i think it went 1-5 with 5 being a 50% boost so if it's set like that then that will put a lot of strain on the bulb
maybe try running it at 1 and see what happens

I have the manuals and circuit diagrams for most of the system somewhere
I'm sure a good electronics person can work out what is going on no problem
it's pretty basic stuff

an electronics person could measure the voltage at the bulb
it should never be more than 120v

hope that helps somehow

robin

[Steve Sherman]

I have been trying to figure out this strange light issue I have been experiencing on my Ilford 500H head on my Durst 138 Enlarger. The Enlarger and head was left sitting for about 6 months, after which I purchased it from a friend. The enlarger appeared to work for our test before the purchase, but since has had issues. The first time the bulbs blew, I was raising the enlarger while the focus light was one, and the power cable from the head to the power supply had slight strain put on it, which caused both bulbs to blow. I replaced both bulbs and the enlarger was then working again for approximately 3 prints. The bulb with the green dichroic filter blew, while the bulb under the blue dichroic filter was still in tact. I again replaced just the one blow bulb and this time was able to get through 24 contact sheet prints before the same bulb blew. I again replaced the bulb, and was able to print another 13 prints before the green dichroic bulb again blew.

Having posted to the forum and heard people's suggestions that perhaps the light chassis were corroded, I went ahead and replaced both halogen chassis. Today when I returned to the darkroom to reaffix the head with the new chassis, I placed two brand new halogens into the chassis and turned on the power supply to find that only the bulb in the blue dichroic filter chassis worked. Both bulb were in tact, and when I switched the bulbs to the opposing chassis, the same thing occurred where the bulb in the chassis with the blue dichoic filter lit while the bulb in the chassis with the green dichoic filter did not turn on.

I am completely perplexed. To add to this I have noticed that on the Power Supply for the Ilford 500H, the light in the power button has blown out in the past few weeks along the same timeline as these issues. I am wondering if there may be an issue with the power supply that is causing this strange problem.

Thanks,
Diana

I to think the problem is likely in the power supply, I would find an electronics shop and look for a gentlemen with gray hair and explain the sequence of how and when the bulbs blow. One other source I've had problems with my own 500 head is the micro switch that is compressed with the front main door is closed there is a little round pin that compresses that switch, my interior plate sometimes moves and doesn't always make up with the male pin that pushes the switch in when the door is closed. Good Luck.