Zone VI Type II power switch

[Edward Pierce]

The power switch in the head of my Zone VI Type II enlarger just stopped working. Fortunately it’s stuck in the “on” position, so I can still use it with a switched power strip. Has anyone ever tried replacing one of these power switches?

[Jody_S]

If the power switch is that red square thing in the top right. that should be a standard part available through many online electronics places, and the repair shouldn't be complicated. Best to remove the old one before ordering new, so you know the exact configuration, as there can be variants (single or double pole, etc).

[Greg]

It's been many, many years.... I remember a rocker switch (power) on the top right of the head on the Zone VI enlarger that I was using. It also had a small red light built into the switch. The rocker switch was sometimes sticking so I replaced the OEM rocker switch (with the small light) with a plain larger heavy duty rocker switch. Remember doing that without having to take the head off. Prying out the OEM switch was a pain. I think it had tabs on the top and bottom that secured it to the head. Wired up the larger rocker switch and easily pressed it back into the switch opening. Back then there was an Allied Electronics (?) store nearby which I took the OEM rocker switch to get the replacement. Only thing that I distinctly remember is removing the switch and testing the power wires only to discover that I didn't unplug the cord.

FYI: Over the years I have used many ZONE VI enlargers. One or two of them had different electrical and switch setups, so the above might not apply to your enlarger.

Good luck

[Greg]

Forgot to mention: Make sure the enlarger is plugged into a GFI protected outlet. I once bought a 4x5 Durst Laborator enlarger locally. The seller plugged it into an outlet to show me that the enlarger worked. When I got the enlarger home and into my darkroom, I plugged it into a GFI protected circuit. Whenever I turned the enlarger on, the GFI would immediately "pop". Took the simple electrics in it apart and discovered a very small frayed wire that was the culprit. The or a previous owner had replaced a switch but poorly connected the power wires to it.

[neil poulsen]

Gfi?

[Greg]

Gfi?

https://www.osha.gov/electrical/hazards/grounding/gfci

https://home.howstuffworks.com/question117.htm

http://hyperphysics.phy-astr.gsu.edu/hbase/electric/gfi.html

[Edward Pierce]

It's been many, many years.... I remember a rocker switch (power) on the top right of the head on the Zone VI enlarger that I was using. It also had a small red light built into the switch. The rocker switch was sometimes sticking so I replaced the OEM rocker switch (with the small light) with a plain larger heavy duty rocker switch. Remember doing that without having to take the head off. Prying out the OEM switch was a pain. I think it had tabs on the top and bottom that secured it to the head. Wired up the larger rocker switch and easily pressed it back into the switch opening. Back then there was an Allied Electronics (?) store nearby which I took the OEM rocker switch to get the replacement. Only thing that I distinctly remember is removing the switch and testing the power wires only to discover that I didn't unplug the cord.

FYI: Over the years I have used many ZONE VI enlargers. One or two of them had different electrical and switch setups, so the above might not apply to your enlarger.

Good luck

Thank you. My switch setup matches your description. I’m relieved to hear that I can pull the switch out without having to disassemble the head. Sounds like there might be enough wire length to work with.

[nolindan]

Thank you. My switch setup matches your description. I’m relieved to hear that I can pull the switch out without having to disassemble the head. Sounds like there might be enough wire length to work with.

You might, however, find it easier to disassemble the head to the extent you can get to the back of the switch. Those switches are meant to snap in but not to snap out - it will take a concerted effort with a screwdriver to pry it out, accompanied by a lot of cussing, scratched paint and band-aids (the band-aids are good for both your fingers and to protect the paint). If you can get to the back of the switch then squeezing the mounting ears with a slip joint wrench or cutting one of the ears off with a pair of diagonal cutters is a much simpler proposition that won't do a number on your blood pressure.

Some snap-in switch designs are such that you will not be able to pry them out from the front.

OTOH, if the switch doesn't match the gauge of the sheet metal, or the hole is oversize, the switch may pop out easily - this would be a design defect that would not make UL happy but will make your job a lot easier.

Two leading distributors for electronic parts are https://www.digikey.com/ and https://www.mouser.com/. They both take small orders, maybe because they both got their start in the 70's supplying electronics for hobbyists. Newark/Element14/Farnell/Avnet (the firm changes its name with the seasons) https://www.farnell.com/reach/is another source that now takes small orders - Farnell has a strong global presence.