Randy, I don't know who built that timer, but I'd guess he's OCD! I've seen factory made stuff that wasn't that neatly made!
Randy, I don't know who built that timer, but I'd guess he's OCD! I've seen factory made stuff that wasn't that neatly made!
I think the only easy way to get a 60Hz AC supply is with an inverter. I don't know how well that would work; your timer probably expects a clean 60Hz input, and an inverter might generate some noise.
I’m sure I am stating the obvious, but why don’t you re-mark the dials with times adjusted for the 20% difference, so 1 minute would be 1:12 etc. what you need for printing is consistency, not timing in one-second or one-minute intervals.
a device that has proven itself from the best side not a few times, proven by time and experience. At the present time, in fact, everything has to be rebuilt by yourself, adding your own components.
Last edited by LeonardDowd; 20-Dec-2020 at 05:20.
its in the manual.....
https://www.vintage-radio.info/heathkit/
its a pdf as PT-15
scroll down past the oscilloscopes.
Thank you.
Quote Originally Posted by Snoopy-16 View Post
I have just bought the PT1500 Heathkit darkroom timer. It was previously used in the USA. As I’m in Australia, I need to convert it to run on 240V. I have found a manual on EBay UK & the seller has just posted it, but has just told me it’s going to take 12 weeks to be delivered!
Does anyone have the build manual & could post / email the relevant section on setting the transformer to switch from 120V to 240V that you would not mind sharing, so that I can get this timer working now?
Thanks in advance 😊Looked at schematic posted by Paul Ron (for the PT-15) and there is nothing there that depends on the mains frequency. Indeed, the specs section explicitly states 50/60cps.It also needs to run on 50hz down there or times will be 20% off.
But in case your PT-1500 is significantly different from the PT-15 and does depend on mains frequency, what is the real drawback of running 20% slow, if used as an enlarger timer? You do test strips, anyway, right? So why not time all your exposures in pseudo-seconds? As long as the times are consistent between test strip and actual exposure, you should be doing fine. A 60Hz inverter would be overkill.
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