Want to Buy WTB: LPL 4500 power supply

[bunop]

I rescued an LPL 4500 from the landfill, but it did not come with a power supply.
Does anyone have an extra one lying around?
120V or 220V will work fine for me.

Thank you in advance!

 

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[eddie]

I think KHB carries them.

 

[bdial]

Nice landfill find!

The power supplies are hard to find second-hand, and pretty dear to buy new. I think KHB sometimes has "reconditioned" ones along with new.

When mine died a few years back I cobbled up a substitute by hooking the lamp up to a household dimmer. The fan operates on line voltage.
That worked well for me until I located a replacement.

The standard bulb for the LPL is an 82 volt 200 watt or 250 watt for the XL version.

Another possibility might be to substitute a 24 volt power supply from some other type of enlarger that uses a 24v 250 watt bulb and adapt the wiring. Some of the Beseler color heads use 24 volt lamps. So far as I know the MR16 base lamps all use the same pin spacing.

 

[bunop]

I think KHB carries them.

Thanks! I inquired and their power supplies are really pricey

 

[bunop]

Nice landfill find!

The power supplies are hard to find second-hand, and pretty dear to buy new. I think KHB sometimes has "reconditioned" ones along with new.

When mine died a few years back I cobbled up a substitute by hooking the lamp up to a household dimmer. The fan operates on line voltage.
That worked well for me until I located a replacement.

The standard bulb for the LPL is an 82 volt 200 watt or 250 watt for the XL version.

Another possibility might be to substitute a 24 volt power supply from some other type of enlarger that uses a 24v 250 watt bulb and adapt the wiring. Some of the Beseler color heads use 24 volt lamps. So far as I know the MR16 base lamps all use the same pin spacing.

Thanks for the tips.

May I ask where you were able to locate your replacement?

 

[bdial]

...May I ask where you were able to locate your replacement?

Don't remember exactly, I think it was ebay. Could have been here, but it was 7 or 8 years back either way, and (I don't mean to sound discouraging), it took me a couple of years to find one for sale at a price that was workable for me at the time.

Unless you're willing to spend possibly a lot of time finding a used one, you may need to pony up whatever KHB wants for a new one, or else hack an alternative. That would certainly be my approach if I have to do it again. But, I have the tools for doing that. A 24 volt /200 watt supply from some other enlarger might be the easiest hack. Next might be what I did and use a dimmer to supply 82 volts for the lamp, but for that you need a meter to set the dimmer to the right voltage. Much more complicated might be to convert the enlarger to LEDs. Not hugely difficult, in my estimation, but there would be lots of fiddly details to work out. Much depends on how comfortable you are with electrical stuff. Another thought; it might be easier able to find a non-working one, then factor in getting it fixed, either by someone local or KHB.

 

[MattKing]

If you can do modifications, there are Beseler power supplies for the 67 series dichro heads that supply 82 volts.

 

[mrosenlof]

I have read (on the internet! it must be true) that 82 volts is what you get with a half wave rectifier on 120 VAC. If that's correct, it would probably be a relatively simple DIY project. I'm not an electrical engineer, but can do simple circuits.

 

[AgX]

Just take a Variac and a multimeter, if 82V AC is all you need.

 

[Ian C]

Here’s an enlarger power supply using only two simple components. It’s intended to power an 82-volt quartz-halogen enlarger lamp. I don’t know if the power is sufficient for a 200-watt or 250- watt lamp. This is probably the simplest design possible.

You might have to choose a different diode and resistor combination for sufficient power for the lamp in the LPL 4500.

http://www.blogintrigue.com/2008/11/omega-c700c760-power-supply/

 

[AgX]

"What I found was a very simple AC-DC “half-wave rectifier” power supply comprised of a power resistor and rectifier diode. This essentially ‘cuts’ the bottom half of the AC sinewave, essentially resulting in 60V RMS DC. This provides about 1.4xRMS peak voltage (1.4 x 60V = 84V), very close to the 85W ESJ bulb specification."

But this does not explain the use of the in series 1Ohm resistor found at the Omega head. The linked Wikipedia article does not even mention such resistor. Is it used to gain a minimum resistance in case of the lamp filament burning trough? Makes no sense to me.