Help needed setting up enlarger

Making your print in the darkroom
Nathan Everett
Posts: 56
Joined: 08 Nov 2013, 08:31
Location: North Rocks, NSW

Help needed setting up enlarger

Postby Nathan Everett » 25 Sep 2014, 18:44

Well, this is my first time setting up an enlarger and to be honest it has me a little miffed. From reading the instructions (and using past enlargers at TAFE etc) it is my understanding that the timer is plugged into the mains, and the enlarger to the timer through a power supply. The equipment that Patrick has given me to play with includes:

- Enlarging timer which has a US plug for connecting to the mains, and two US plug outlets (one for the power supply/enlarger and the other for the safelight)
- A 12V laptop type power supply with Aussie plug at input, and a DC jack as output. (should I be using a 'conventional' transformer used for halogen downlights instead?)
- LPL C6700 enlarger with a US plug. I've bought a couple of 12V 100w lamps for this.

To get this all connected and running I'm proposing to do the following:

- Cut off US power plug from the timer and connect Aussie plug so it can be plugged straight into home power point.
- Modify a 12V laptop power supply by:
1. At input side cut off Aussie plug and connecting US plug (so it can plug into the timer)
2. At output side cut off DC jack and cut off US plug from enlarger and splice together

I guess my main question is whether this is the best way to go about setting it all up? If it is, I wanted to check that polarity won't matter in the enlarger when I splice as the power is DC, and check whether I'll blow up the timer by plugging it into the mains as our Aussie voltage is double that in the US.

Is this the easiest way because it sure seems like a pain in the date but I can't see another way of doing it. Any help will be really appreciated!

Walter Glover
Posts: 883
Joined: 31 Jul 2012, 22:31
Location: Leichhardt, NSW

Re: Help needed setting up enlarger

Postby Walter Glover » 25 Sep 2014, 21:16

I have only ever dealt with fully 240 volt units. I am of no help. Sorry.
Walter Glover

"Photography was not a bastard left by science on the doorstep of art, but a legitimate child of the Western pictorial tradition." —Robert Galassi

Nathan Everett
Posts: 56
Joined: 08 Nov 2013, 08:31
Location: North Rocks, NSW

Re: Help needed setting up enlarger

Postby Nathan Everett » 25 Sep 2014, 21:57

So if I bought a 240V US timer and a US power supply I could just use a simple US to Aus plug adapter at the mains? Is this what is typically done? Sorry for my ignorance, this is my first time trying to set up something like this...

Walter Glover
Posts: 883
Joined: 31 Jul 2012, 22:31
Location: Leichhardt, NSW

Re: Help needed setting up enlarger

Postby Walter Glover » 25 Sep 2014, 22:11

The whole US business is totally unknown by me.
Walter Glover

"Photography was not a bastard left by science on the doorstep of art, but a legitimate child of the Western pictorial tradition." —Robert Galassi

Lachlan717
Posts: 487
Joined: 03 Aug 2012, 16:49

Re: Help needed setting up enlarger

Postby Lachlan717 » 26 Sep 2014, 05:00

What's the stated power req on the enlarger?

Nathan Everett
Posts: 56
Joined: 08 Nov 2013, 08:31
Location: North Rocks, NSW

Re: Help needed setting up enlarger

Postby Nathan Everett » 26 Sep 2014, 09:11

The enlarger manual calls for a 12V power supply and for a 12V/100W lamp. The timer that I have requires 110V so I'd be really reluctant to try using it here without connecting a transformer to it first, since these are cheap maybe this is the best option?

Nathan Everett
Posts: 56
Joined: 08 Nov 2013, 08:31
Location: North Rocks, NSW

Re: Help needed setting up enlarger

Postby Nathan Everett » 26 Sep 2014, 13:28

Given up on the step-down transformer option. The timer needs about 600W power and to get a transformer big enough is about $400. Looks like I'll be buying a 240V timer from the states and rewiring an AU plug to it. The GraLab 300 comes in a 240V 50Hz so might get one of these. It seriously shouldn't be this hard...

steve
Posts: 4
Joined: 01 Jun 2013, 11:54

Re: Help needed setting up enlarger

Postby steve » 29 Sep 2014, 18:32

Okay, the max power rating of the timer is 600W. It does not require 600W but can handle up to 600W.

It sounds like the timer itself is superfluous - it can't be used to switch the transformer since it is 110V in/out. Connect the transformer directly to 240V and the enlarger and the enlarger should work. You'll need a timer (unless you want to use a stop watch and the main power switch) - the one you have can't be used. Using a stop watch isn't out of the question - didn't some of the old-timers use a metronome?

I'd put off getting a timer until you work out if you need one. One of the problems with the switch-mode power supplies you have is that it can drive the load after the 240V is removed - see if this is a problem for you as you may need a different power supply (ie. turn the transformer off at the mains and see if the enlarger stays on briefly - this will affect your times).

Hope that helps - let me know if anything is unclear.

cheers
-steve

Nathan Everett
Posts: 56
Joined: 08 Nov 2013, 08:31
Location: North Rocks, NSW

Re: Help needed setting up enlarger

Postby Nathan Everett » 30 Sep 2014, 15:16

Cheers Steve, what you said about the power supply made sense - I plugged it into the mains and even after switching it off it held power for a while making it no good to use. To get around using a power supply I caved and bought a 500W 240/120V step-down transformer effectively giving myself US mains supply. Tested the timer and it works perfectly. Plugged the enlarger into the timer, connected a spare 85W 82V lamp into the enlarger head. Fired it up and it all worked for a split second before the lamp blew haha! From the LPL enlarger guide on the KHB website I'm gathering this is the correct way of setting up in the US and Canada (or here with the step-down transformer), and that everywhere else with 240V mains the 12V power supply is needed with the 12V lamps? I'm hoping the lamp blew simply because it old and not because there's a problem with the power... I'll feel pretty beaten if I buy a few spare globes and blow them straight away.

steve
Posts: 4
Joined: 01 Jun 2013, 11:54

Re: Help needed setting up enlarger

Postby steve » 01 Oct 2014, 01:36

Hi Nathan,

There's a lot going on here.

It sounds like you have the basic setup correct: power point -> step-down -> timer -> power supply -> enlarger

If the enlarger worked properly with the 12V Australian supply, then you likely have a 100W 12V lamp. Hooking it up to the 82V american supply will kill the lamp quick, although you should check all the fuses in case you got lucky.

If you want to continue with the 110V setup, all you need to do is swap in an 85W 82V lamp. KHB are a good source, just specify air mail (Canadian surface mail takes months to arrive). Make sure you get spares :-)

If you want to swap to 240V, you drop the step-down transformer, add a 240V timer, swap the 82V supply for a 12V supply (get a 12V AC supply - no delay in turning the enlarger off), and go with 100W 12V lamps. 12V AC supplies are fairly common - they're used for garden halogen lights. Get one in the 120-150VA range. You'll likely need to do some wiring on the 12V side - never touch the 240V side and only work with everything unplugged (12V is fairly safe, but better safe than sorry). It would be wise to add a fuse holder and 10A fuse in one of the leads if the supply doesn't have one.

By the way, the 500W step-down is overkill - if you can return it, swap it for a 120-150VA step-down.

If you have any questions or if anything is unclear, let me know.

cheers
-steve


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