Please help with an old beast: ilford 400HL trouble

[amandahuginkiss]

Hi all,

I have two issues with my Ilford 400HL multigrade enlarger head.

Most importantly: one of the two bulbs is no longer illuminating and I believe the problem lies with the lamp-holder (the bulbs themselves are fine as I've tested them on the still working holder - unless it is something to do with wiring/circuitry in the timer, which is beyond my current knowledge).

If it is the lamp-holder that has stopped working, the exact replacement (QCX-34-12") seems to be discontinued and only available in the states with pricey shipping fees. The original lamp-holder actually seems to have much higher max capacity wattage and voltage (750w 300v) (see ebay listing here) than the bulbs specified in manual - 30v 80w.

So my question is, what voltage and wattage should I be looking for in a replacement lampolder? Will a 25V, wattage unspecified one do? (here) I also assume high temperature wire/ceramic/halogen would be preferable, but is there anything else I need to be aware of.

My second subsequent issue is whether it will be okay to power this set-up from the mains. Before one of the lamps stopped working, I was powering the enlarger from the mains via the ilford 400C control unit. As far as I can tell this is what the manual recommends, and it worked happily for 6 months. I am just checking I do not need a transistor for this?

Many thanks for your help in advance - i would appreciate any advice!

thank you!

 

[koraks]

Welcome aboard @amandahuginkiss !

Will a 25V, wattage unspecified one do? (here)

Sorry, that link doesn't work; please try posting it again.
In general, the socket will need to have equal or higher ratings for, voltage, current and power to the actual application parameters. So if it's actually a 30V bulb, the socket should be rated for at least 30V. However, I don't expect a 25V-rated socket will present a problem if it's run at 30V since there's not a whole lot to go wrong in that sense. Current and/or power ratings are more important for both the leads and the contacts in the socket.

As far as I can tell this is what the manual recommends, and it worked happily for 6 months.

So that should be fine; if the head is rated for your mains voltage, it should be OK.

I do not need a transistor for this?

You mean a transformer. This can be required if you run e.g. a device rated for US mains of 115V from a 230V outlet or vice versa. Again, if the device is rated for the outlet voltage, you don't need a transformer.

I can't help you on the specific options for the bulb sockets other than voicing my expectation that there are likely plenty of suitable sockets on the market that can be had for a pittance. It's been ages since I got rid of my Ilford multigrade head though.

Edit: a quick search shows that the bulbs fit into a GX5.3 socket, you might want to search for that and purchase a couple of porcelain sockets that seem to fit the bill and then install/transplant those.

PS:

The bulbs themselves are fine as I've tested them on the still working holder - unless it is something to do with wiring/circuitry in the timer, which is beyond my current knowledge

Failure of the contacts in the bulb socket is indeed a likely scenario, but by far not the only possibility. However, it's a decent enough place to start as a replacement socket is fairly cheap and easy to install. You might also try cleaning the contacts in the present socket as a 'failed' socket is often a problem of corrosion/oxidation/fouling of the contacts. Ensure that the enlarger is unplugged from the outlet and take a sharp implement (a sturdy needle etc.) and try to remove whatever muck is on the contacts. Sometimes the contacts can be physically removed from the socket, making it a little easier to clean the contact surface. I don't recommend this as a permanent solution, but it can temporarily work to demonstrate if the socket is indeed the problem.