Converting Ilford 500S Power Supply between 120V, 220V and 240V

My ageing Ilford 500 system is in need of more regular maintenance—I hate to say this, but I am thinking of replacing it with a VCCE, however the chassis of my De Vere 504 is so good, this is a hard decision to make. In the meantime, I bought a replacement 500S power supply from US via ebay. It was a 120 V supply, and it was the type without the voltage selector, which would normally be found as a ring around the fuse chamber, on the back of the supply. I have compared the wiring of my existing supply with the US one, and having checked the diagrams, I could see that the power transformer is a universal item, and the only differences were in the wiring of the terminal block located on top of it.

I have attempted the conversion. It was successful. If you are looking for a replacement supply and can only get the US ones, this post might help you. A few caveats:

• There are at least 3 versions of the 500S. I have the 2nd generation one, serial number beginning "5S2". The later ones have different wiring, but a conversion should also be possible, using different instructions to mine.
• This is the non-UL model. The UL models can be recognised by having the enlarger head socket with 7 flat and 1 round pins. This model has 8 flat pins.
• If you decide to follow this post you accept and agree that you may willingly experience shocks, repeated electrocutions, fire, sudden death, irritation, swearing, or a visit from (insert your government name) (insert benevolent-sounding terms like "travel" or "safety") department. NO guarantees offered. Do it at your own risk.

I suggest you also review a few other good threads on APUG, including:

• Wiring diagrams for this model of the supply, as well as some of the other ones: http://www.apug.org/forums/forum43/85596-help-electrical-diagrams-ilford-heads.html
• Schematics of the controllers: http://www.apug.org/forums/forum43/62359-ilford-500c-controller-electronic-circuit-diagram.html
• Service manual and diagrams for the newer (UL) models, direct from Ilford (this is not the one I changed): http://www.ilfordphoto.com/products...igrade 500 Exposure System Service Manual.pdf

So, what do you need to do? Ensure you have the model I am referring to:

• No voltage selector on the back.
• Open it up (2 screws on each side panel, then gently slide apart the casing, exposing the terminal connector block placed on top of the power transformer).
• There should be only 1 (not 2) printed circuit boards inside, on the side panel.
• The terminal block of a 120V unit without a voltage selector should look like this:

However, if it has more wires and looks like the one below, then your model has the voltage selector. Do not follow my suggestions, instead use the selector to switch the voltage to 220 or 240 or 120, as needed. Don't forget to replace the fuse.

If your model came as 120V, and you would like to make it into 220V:

1. Disconnect and remove blue wire connecting terminals 8 with 9.
2. Disconnect yellow wire connecting terminals 6 with 11, from terminal 11, and connect it to terminal 9, so that it now connects terminals 6 and 9.
3. Disconnect yellow wire marked "56" from terminal 11 and connect it to terminal 10.

Your terminal block should look like this now:

If your model came as 120V, and you would like to make it into 240V:

1. Disconnect and remove blue wire connecting terminals 8 with 9.
2. Disconnect yellow wire connecting terminals 6 with 11, from terminal 11, and connect it to terminal 9, so that it now connects terminals 6 and 9.
3. No need to change anything regarding yellow wire marked "56", i.e. it should remain connected to terminal 11.

If your model came as 220V or 240V, and you would like to make it into 120V:

1. It should have the voltage selector, use it. If it does not, then ensure:
2. Terminals 6 and 9 are not connected with a yellow wire.
3. Terminals 8 and 9 should be connected, preferably with a blue-coloured wire.
4. Yellow wire marked "56" should be connected to terminal 11 (not 10).

After making the change, ensure you have the correct fuse in the fuse chamber, accessible at the back of the unit. It should be of type 4.0A T for 220/240 installations and 6.3A SB for 120V ones.

By the way, if you are not sure if to convert your unit into 220V or 240V, using 240V is a safer choice and will slightly extend the lamp life, at the minor cost of light output. 220V will burn your bulbs more often if you have what is currently the "norm" of 230V in EU. However, if you happen to have a stabilised voltage supply that delivers real 220V (not some 220V +- 6% as many solid-state stabs do), then using 220V is the best option. I use one of those, rather ancient, electro-mechanical stabilisers, that were made by Rialto for De Vere some time ago. Amazing stuff, keeps 219-221V all the time, even with 15% input swings.

Finally, here is the wiring diagram, thanks to the other thread, with my mark-up showing the necessary connections replacing the absent voltage selector, in blue:


Good luck...

 

Thanks, Dale.

 

I am very sorry for your disappointment, Richard, but it sounds like you may have attempted these modifications in an era when risks where more readily taken, and people went to the moon, rather than to a lawyer.