Need Timers

[Mars]

Hi there! My name is Mars and I am a photography teacher at a public high school. I am in desperate need of timers 4 or 5, for a dark room that has been neglected for years. I want to revive the dark room. Do you know where can I can get timers at a discounted rate? We have made photograms the students love the process, we have about 4 enlargers that work. My classes have about 40 students in them. I would like to be able to get enough timers so that all the enlargers have a timer. Thank you!

 

[jim10219]

eBay. I bought a cool looking mechanical darkroom timer that keeps good time for around $10. It's probably 70 years old, but it works as well as the day it was made.

 

[voceumana]

Realistically, your best choice is ebay. The Time-O-Lite 60 Second enlarger timer sells for around $500 at BH photovideo, and used on eBay they go from between $10 and $50. If you have an electrician on staff or available you can have them inspect them for safety.

 

[Svenedin]

The Durst "Tim 60" comes up on eBay. It's robust, simple and easy to use........may even be student resistant.

 

[Neal]

Dear Mars,

You can find mechanical wind up timers like this on ebay. They aren't the greatest but I used one for a decade before I could upgrade the darkroom. I think I gave it away but I will check the attic and if it is still there I will be happy to mail it to you.

Good luck,

Neal Wydra

 

[voceumana]

You can always provide a metronome set for 1 second clicks and then the students can count the clicks. Since a metronome for each enlarger would confuse, you could set up an electronic metronome, and have headphones for each enlarger.

 

[Mars]

Hi! Just bought a bunch of timers on ebay. Unfortunately, they only take two prong plugs, my enlargers take 3 prongs. Anyone know what to do about this?

 

[voceumana]

Whoever does electrical repairs for your school should be able to address this issue. The timers need to be modified for a 3-wire power cord, and then have the cases grounded and adapters added to make the ground connection to your enlarger plugs. It's important that whoever does this is familiar with electrical code wiring.

 

[jim10219]

Hi! Just bought a bunch of timers on ebay. Unfortunately, they only take two prong plugs, my enlargers take 3 prongs. Anyone know what to do about this?

Keep everything else the same, but connect the new ground wires directly to the chassis with a nut, bolt, and star washer. Be sure to remove any paint and corrosion at this point so you get a good connection. Remember, the left, larger slot/blade is the neutral (black), and the right smaller slot/blade is the hot (white/red). Do it for both the new outlet and new power cable. If you open it up and get confused about what goes where, find someone who knows more about this stuff. It should be fairly basic, but you don't want to take a risk with someone's life on an attempt at your first electronics project.

 

[voceumana]

Maybe you should just buy the 3-prong version of the timers instead? The socket for 3-wires is obsolete and expensive ($10). See http://www.surplussales.com/electrical/ElecAC-1.html part number 160-10N. Wiring in the timer is very difficult because of lack of space. Changing out the power cord would even be difficult--just opened up one of my timers to see.

 

[Chan Tran]

Steal the metronome from the music department and have the students count the seconds.

 

[CMoore]

Maybe you should just buy the 3-prong version of the timers instead? The socket for 3-wires is obsolete and expensive ($10). See http://www.surplussales.com/electrical/ElecAC-1.html part number 160-10N. Wiring in the timer is very difficult because of lack of space. Changing out the power cord would even be difficult--just opened up one of my timers to see.

Yeah...it is going to be Way Easier/Cleaner to buy 3 Wire timers.
That said.....how old are these timers and what brand are they.?
The timers for my Enlargers have a digital readout and are newer, but even my old Gralab 300 has 3 wire power.

 

[Mars]

Hi everyone, supposedly there is an adapter you can find at a hardware store that will fix this. Thank you for the help and suggestions!

 

[Mars]

Yeah...it is going to be Way Easier/Cleaner to buy 3 Wire timers.
That said.....how old are these timers and what brand are they.?
The timers for my Enlargers have a digital readout and are newer, but even my old Gralab 300 has 3 wire power.

Super old, mechanical , metal timers...."Time o Lite" brand.

 

[mshchem]

My Dad always did one thousand one, one thousand two, one thousand three etc. I didn't have an enlarger timer until I was about 18. Of course in the good old day paper was so slow.......

I would get proper timers. You need to be sure that you GROUND the metal cases on the timers. And that the enlargers are grounded. If you use a cheater plug to adapt the enlarger cord to the non grounded timers nothing will be grounded.

By code you should have everything grounded on GFCI circuits. I had my old original Gralab timer, it was grounded, but every time I touched it it would pop the GFCI. I never got shocked, but it was leaking current somewhere.

 

[Mars]

Dear Mars,

You can find mechanical wind up timers like this on ebay. They aren't the greatest but I used one for a decade before I could upgrade the darkroom. I think I gave it away but I will check the attic and if it is still there I will be happy to mail it to you.

Good luck,

Neal Wydra

Thank you, for the offer, just bought some off of ebay!

 

[Neal]

Dear Mars,

I would like to add to the grounding chorus. The enlargers should all have a ground wire added and connected appropriately, it is very easy to do. The adapter you mention will not perform this function by itself.

Good luck,

Neal Wydra

 

[Svenedin]

I don't know much about US electrical systems but wholeheartedly agree regarding safety especially in an educational establishment. Equipment should be properly earthed unless it is modern double-insulated equipment that specifically does not require an earth connection. All electrical equipment should be regularly tested by a qualified person and certified prior to use according to the standards in place in that jurisdiction. Although this is an enlarger timer and the wet and dry areas of the darkroom should be separated it is not difficult to envision a scenario where a student operates the equipment with wet hands or liquid is spilled accidentally.

 

[CMoore]

Dear Mars,

I would like to add to the grounding chorus. The enlargers should all have a ground wire added and connected appropriately, it is very easy to do. The adapter you mention will not perform this function by itself.

Good luck,

Neal Wydra

Not by itself.?
It does not do it at all. It does the opposite.
It is a Ground Lift device.....with the Horrible Misnomer of a "Ground Adapter"

 

[jim10219]

Not by itself.?
It does not do it at all. It does the opposite.
It is a Ground Lift device.....with the Horrible Misnomer of a "Ground Adapter"

Not if you use it properly. There's a tab on the outside of it. You're supposed to connect a ground wire to that tab. So in theory, you could ground the whole circuit, enlarger and timer, by simply connecting a wire from that tab on the cheater plug to a ground. You could use either the ground on the main wall outlet you're using (if it's grounded) or connect it to the drain pipe on your sink (if it's all metal). Of course, then you've got another wire running around, which is a different kind of hazard in and of itself. And that's kind of confusing to look at, so I could see someone removing that cable thinking it was a hazard or something, or tripping over it, or it just becoming disconnected by accident. A lot of people think grounding a device through the plumbing will make the plumbing a shock hazard. But it doesn't work that way. Anyway, there are a lot of ways that method can go wrong. But the theory behind those plugs was to originally provide a way to ground a device that could only plug into a non-grounded outlet. Leave it to the average consumer who knows nothing about electricity to turn it into a dangerous device.

Though if you use a cheater plug in conjunction with a GFCI outlet, you should be okay. Since in this case, noise isn't really an issue, but rather we're using the ground for safety, a GFCI would actually do a better job at keeping everyone safe from electric shock than using a grounded plug alone. So if the outlets you're using are all GFCI, and in a school they probably should be, then I wouldn't worry about it.

 

[CMoore]

You are 100% correct. That is how they are supposed to be used.
But they also sell lots of new adapters that do not have the ground tab. And a lot of the existing adapters have had that tab broken off.....like extension cords that have the ground pin removed.
That little tab is designed to connect to the cover plate and be screwed down by the little screw that holds the cover plate to the outlet. It theoretically works fine in a "pinch"
It is not a method i would use to permanently ground a darkroom system.
But anyway,.......What the OP really needs are timers with a 3 wire paradigm IMHO FWIW.
good luck

 

[jim10219]

You are 100% correct. That is how they are supposed to be used.
But they also sell lots of new adapters that do not have the ground tab. And a lot of the existing adapters have had that tab broken off.....like extension cords that have the ground pin removed.
That little tab is designed to connect to the cover plate and be screwed down by the little screw that holds the cover plate to the outlet. It theoretically works fine in a "pinch"
It is not a method i would use to permanently ground a darkroom system.
But anyway,.......What the OP really needs are timers with a 3 wire paradigm IMHO FWIW.
good luck

Yeah. Originally those cheater plugs came with a wire for you to ground instead of a tab. But I guess people plugged that wire into the outlet slot below and got hurt, so they went to the tab. The idea of the tab was so people could screw them onto the faceplate of grounded two prong outlets, but how often do you see grounded two pronged outlets? Usually, if it's grounded, it'll be a three pronged. And if they left the outlet as a two pronged, it's usually going to be ungrounded. Screwing that tab to an ungrounded two pronged outlet doesn't do anything but hold the cheater plug in place. So the whole system is pretty messed up. Add to that the fact that a lot of people have replaced their ungrounded two prong outlets with grounded three pronged outlets, but didn't rewire it to make the outlet grounded! And that's worse than using a cheater plug, because at least with a cheater plug, you can make a reasonable assumption that it's not completely safe!

And I agree, rewiring the timers would be the best solution. It would also increase their value at least by the price of the parts. If you saw two of the exact same models, one ungrounded, and one just a few bucks more that was grounded, which would you choose? So you wouldn't necessarily by wasting money, just reinvesting it. You can buy a grounded outlet in the color you want at your local home improvement store for about $2-3 each. A 7ft. grounded extension plug to replace the power cable with is about $5-10 (you might be able to find a cheaper grounded replacement cable by itself, but I often find it's cheaper to just hack off the end of an extension plug). Or, you might be able to find those old grounded power cables somewhere else. Whenever I throw away an old electronic with one of those, I hack it off for future projects (they also make good speaker cables). If you have a computer lab at your school, you could ask if they have a room full of old computers or parts and may be able to hack a bunch of old IEC cables for free. So you're looking at $2-15 in parts per timer to get them working properly and safely, and once you figure out how to do it, probably 15-20 minutes of work each. I did that to an old time-olite I bought off eBay. I think all told, it was around $25. It works well, but truth be told, I mostly bought it because it looked cool! I love Art Deco stuff!

 

[voceumana]

The 3-wire to 2-wire adapters need a socket that is different from the one used in the Time-O-Lite timers. The socket in the timers is built on a tube-socket base, and the appropriate plate mounting screw which is used for the ground connection doesn't exist on the timers.

I've seen these adapters with a wire in place of a metal tab, so the ground could be accomplished with a wire connection to a grounded case, but you'd need to ground the case via a means other than the 2-wire power cable. Replace the cable with a 3-wire cable and connect the cable ground to the case and this approach could work. But the cable on the timers I've seen with -wires do not have polarized plugs, so you really should replace the cables in any case.

In the end, this work will probably cost more than getting some 3-wire timers.

Also, the entire darkroom should be on Ground-Fault Interrupter Circuit protection.

By the way, anyone suggesting rewiring the timers needs to open one up: there is NO extra space inside, so this is difficult work to do. If there were space, it would be relatively easy.

 

[John Koehrer]

What's a "tube socket" base?
At this point we're providing answers for an unknown product.
The Singer or Time-0-light timers(M-59) I've seen since the '60's have been standard two blade or three blade.
Gra-Lab also made a 60 second timer in the same case as their common darkroom 60 minute machine.

 

[voceumana]

A tube socket base is a style of connector used primarily for electron tubes (valves in the UK). This style of connector also offered AC plugs and jacks, that mounted in a circular hole, about 1.15 inches in diameter with a round spring retaining clip. All Time-O-Lite timers I've seen with 2-pin sockets use this style of connector. The ones with 3-pin use a more commonly available rectangular clip-in socket.

You can't use the 2 to 3 pin adapters with grounding tab on this style of socket. There is no screw to attach the tab, and you can't drill one because the shell is bakelite.

You'd have to find an adapter with a wire ground--they were made but are not very common now.