"Mike Wilde, post: 470307, member: 14346"]Lucky me - old hardware solution
I landed an 80's Vivitar 'Process Time Commander' in a darkroom lot buy up a few years ago. It is the cats meow for me. 3 separate 6 step timers that can be set up to run on own, or chained to one another. Digital display(dimmable) shows where it is at and what step and program it is running
It can squack at you when you should start draining, squack when to advance to the next step, counts up how late you are advancing to the next step when you are advancing manually, etc.
There is also a digital timer for enlarging that is more common.
The PTC had an optional temperature probe, and the enlarger timer had a sensor probe. I have never seen any documentation on these, and would love to find out more on them, to home build this functionality.
The power supply modules on these go flaky, but are easily repaired; I have rehabbed three of them, before giving them new lives via *baying them away. Contact me if you have a dead Vivitar timer, and I can guide you to how your electrical fix it man can bring them back if you are not up to it yourself.P
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I have several PTC and the flaky power supply problem as well. The failure is a burned out resister. My crude solution was to install a higher capacity resistor, however I know that the true repair involves some other modification of a minor sort. Unhappily, my knowledge of the electronics here is not up to figuring it out. If you have the repair info, I'd love to have it. The underlying problem is that the power supply stays on an idle current when switched off in order to feed power to the computer section so it will hold programming in its memory when off. Constant power to the supply, even when the operating unit is off, eventually burn out the regular resistor. My larger resistor merely allows the unit to absorb more heat without blowing out, so I have to leave it unplugged between processing sessions, which in turn looses the existing program. I can live with it, but I'd rather not.