GraLab 900 usage (on 240v!)

[welly]

Hi all,

I just "won" a GraLab 900 from eBay. Have a few questions:

- Does anyone here use one on 240v or am I going to have to get a transformer?

- Would I be right in thinking the power out sockets can be used with an enlarger to turn on and off the lamp?

- Can the LED display be turned off entirely (for use with open trays)?

If anyone has any more useful hints and tips for using it, that'd be also welcome!

I think that's it!

Welly

[Leigh]

The Gralab 900 is a perfect choice for tray development, since it supports eight processing steps and advances automatically from one to the next.
I have two of them (bought a backup since they're relatively hard to find, never needed it).

The function for each step can be set to count up or down.
I count down each step until I get to the wash, which is counted up.

It has a beeper function that can be set to tick every minute and every half minute, then rapidly in the last ten seconds. There are other audio options, including once per second.

If it's a US model you will need 120v to power it, so a step-down transformer is in order.
There was an export version set up for 240 volts. You might be able to change that internally.
Either version is rated for both 50Hz and 60Hz operation.

I've never opened mine, so I don't know if the output closures are mechanical relays or semiconductor. Mechanical relays should handle 240-volt loads. Semiconductor types might not.
There are two outputs, one for the enlarger and one for a safelight.

The display can be turned off completely. That's selectable independently for each step.
I leave mine off (tray dev) through the fix, then turn it on for the wash.

The instruction manual is readily available online. I can provide a copy if you can't find it.


- Leigh

[welly]

The Gralab 900 is a perfect choice for tray development, since it supports eight processing steps and advances automatically from one to the next.
I have two of them (bought a backup since they're relatively hard to find, never needed it).

The function for each step can be set to count up or down.
I count down each step until I get to the wash, which is counted up.

It has a beeper function that can be set to tick every minute and every half minute, then rapidly in the last ten seconds. There are other audio options, including once per second.

If it's a US model you will need 120v to power it, so a step-down transformer is in order.
There was an export version set up for 240 volts. You might be able to change that internally.
Either version is rated for both 50Hz and 60Hz operation.

I've never opened mine, so I don't know if the output closures are mechanical relays or semiconductor. Mechanical relays should handle 240-volt loads. Semiconductor types might not.
There are two outputs, one for the enlarger and one for a safelight.

The display can be turned off completely. That's selectable independently for each step.
I leave mine off (tray dev) through the fix, then turn it on for the wash.

The instruction manual is readily available online. I can provide a copy if you can't find it.


- Leigh

Thanks very much Leigh, it sounds brilliant. I'll just have to hang on until it's shipped over but I think it's going to be a very useful device. I just found a PDF instruction manual. It looks easy enough to set up and use. I'm going to have to try and find a foot switch for it I reckon and I think a transformer will have to be bought - there seems to be loads of those for sale on ebay. My only slight concern is finding a suitable transformer that I can also use to plug my enlarger into and I'm also wondering if the output from the transformer is 120v, so not sure how that's going to work with my 240v enlarger. I might have to email the manufacturers for some information on that.

Cheers!

[Leigh]

Hi Welly,

The output for the enlarger should be isolated electrically from the timer circuitry, meaning you should be able to plug the enlarger into the timer outlet and have it work properly regardless of the enlarger voltage.

However, you should confirm this either by physical examination (looking for a relay) or by contacting the manufacturer.

Given that they did have a 240-volt export version, the output circuitry is likely designed to work with that voltage.

- Leigh

[Brian C. Miller]

Uh, waitaminit, the output isn't switched separately, it's fed from the timer's input. So if you run it off 120V, you'll get 120V at the output. If you have an enlarger set up for 240V, either have the timer trigger a relay, or else change the enlarger's bulb. Triggering a relay is quite common, as that's how the larger enlargers are run.

Yes, I love my GraLab 900.

[welly]

I might have to tap some of your electronics expertise. I had an email back from DimcoGray and they said they "did not see any way you could set it up to work with 240v". I shall not be beaten.

Brian, the output from the Gralab would go into some kind of relay and the relay would in turn switch on and off the connection to the enlarger I assume? I'm guessing I need something like this:

http://www.jaycar.com.au/products_uploaded/SY-4084%20Data%20Sheet.pdf

[Brian C. Miller]

Right.
Transformer -> GraLab -> relay -> enlarger

The coil side of the relay would take 120VAC, and the switch side would take the 240VAC to run the enlarger. Any electrical supply house should have the appropriate part and an electrical box for it. If you feel queasy about crimping a few wires, any electrician should be able to do it for you.

Technically, DimcoGray is right in that many parts in the unit would have to be replaced. But it's quite easily to use it isolated. My D5 and Chromega heads must be used through a relay, and I'm sure other enlargers are used the same way.

[welly]

Right.
Transformer -> GraLab -> relay -> enlarger

The coil side of the relay would take 120VAC, and the switch side would take the 240VAC to run the enlarger. Any electrical supply house should have the appropriate part and an electrical box for it. If you feel queasy about crimping a few wires, any electrician should be able to do it for you.

Technically, DimcoGray is right in that many parts in the unit would have to be replaced. But it's quite easily to use it isolated. My D5 and Chromega heads must be used through a relay, and I'm sure other enlargers are used the same way.

Awesome, thank you. I'll pop down to the local electrical shop and get on with it. Cheers!

[Leigh]

Technically, DimcoGray is right in that many parts in the unit would have to be replaced.
If that's true, it's a butt-stupid design, considering they did offer a 240-volt version of the product.

Obviously the power connectors (in and out) would be different, but otherwise the components should be the same.

- Leigh