2 enlarging timers counting too long?!?

[Kurt.Strecker]

My craigslist darkroom setup came with a spiratone enlarging timer that seemed a little schizophrenic. the "go" button was finicky, but even when that worked it seemed to count out more time than it was set to.

So I bought a Beseler Audible/Repeating enlarging timer, since that was what we used in school and it had a warm fuzzy place in my heart.

But this one, too, seems to count too long. When pit against a Gralab, and when audible beeps are counted (by me, in my head) it's going way over the time it should be set to.

when set to 2.0 in 10x (20 seconds) it's counting to 24. When set to 3.0 in 10x (30 seconds) it's counting to 38. AH HA! I said, surely when I set it to 4.0 in 10x (40 seconds) it'll count to 52!!

but the pattern didn't hold, it counted to something closer to 1:05 . . .

do these things crap out with age?

I guess it doesn't really matter, as long as it stays somewhat consistant over the next span of time in which I'm using it . . . Just curious?!?

 

[Denis R]

ideas..

what is your power quality? harmonics, frequency, voltage, clean sine wave

try a time-o-lite

use a left hand clock

 

[Marco Gilardetti]

I guess it doesn't really matter, as long as it stays somewhat consistant over the next span of time in which I'm using it . . . Just curious?!?

Frankly speaking, I never ran into a photographic timer that actually delivered the seconds written on the dial. Most of the dials do not bear the writing "seconds" anyway. In most cases those are only arbitrary units. And yes, as the timing is usually based on a capacitor being charged through a series of resistors, and both these components show change of precision with age, timers do show some ageing. But the important thing, as you said, is that 40 units are consistently twice the time of 20 units. That's all one needs.

 

[Rick A]

I have several models of Gralab and Tim-o-lite timers,including a Gralab 525 digital. I checked all my analogue timers against the digital by plugging the analogues into the digital and set them at the same times. I then used the digital to turn on the timers. All of my timers shut off simultaniusly. Not one shut off prematurly, or had time remaining when the digital ended. Maybe you should try this with your timers, if for no other reason than to see if they are all the same, or weed out a defective timer.

Rick

 

[Kurt.Strecker]

I took apart the beseler timer. There are 3 adjustble resistors (seems like they're resistors anyway).

One of them adjusts the speed of the audible metronome.

One of them adjusts the timing of the 1x setting

The last adjusts the timing of the 10x setting.

But the 10x setting adjustment isn't linear. I can line it up for, say, 20 seconds to time out to exactly 20 seconds, but every time less than 20 seconds will come up short, and every setting above 20 seconds will go long.

It seems the best combination is one in which 60 seconds lines up pretty close, and 10 seconds comes out to closer to 9 . . . Or, I could set it for 10 seconds to be spot-on and simply give multiple exposures of exaclty 10 seconds to stack to the exposure needed . . .

ah well, my first ebay fail . . . could be much worse.

 

[Rick A]

I took apart the beseler timer. There are 3 adjustble resistors (seems like they're resistors anyway).

One of them adjusts the speed of the audible metronome.

One of them adjusts the timing of the 1x setting

The last adjusts the timing of the 10x setting.

But the 10x setting adjustment isn't linear. I can line it up for, say, 20 seconds to time out to exactly 20 seconds, but every time less than 20 seconds will come up short, and every setting above 20 seconds will go long.

It seems the best combination is one in which 60 seconds lines up pretty close, and 10 seconds comes out to closer to 9 . . . Or, I could set it for 10 seconds to be spot-on and simply give multiple exposures of exaclty 10 seconds to stack to the exposure needed . . .

ah well, my first ebay fail . . . could be much worse.

Kurt, does it matter if your timer is off-as long as it is consistant? If the times you are using work, and the timer runs the same every time, and does not vary, then it should be alright to use it. Just keep in mind what it does, and adjust your print times accordingly.If you set time for 20 seconds, and it gives you a perfect print, who cares if it is actually 22 seconds? All I am saying here is use it until you find an another timer that is accurate.

Rick

 

[Neal]

Dear Kurt,

After reading your post, I just had to go and check my old Omega E-99 timer. It is good up to a minute. In any case, years ago I used a mechanical timer that I'm certain was not as good as yours. Now that you have it adjusted I'll bet everything works out just fine.

Neal Wydra

 

[bsdunek]

A standard mechanical timer with a synchronous motor (old fashioned clock motor), will be a accurate as the frequency provided by the power company, which is very accurate. This is assuming it is in fairly good shape. Dirt or corrosion in the bearings can slow it down. I have two ancient Time-O-Lights and a GraLab, and they are all together, just like rainphot says.
Electronic timers that use an internally generated frequency can change over time as the components age.
As said, if they are consistent, it really doesn’t matter. If they aren’t, pitch them.

 

[DWThomas]

In my limited experience, early electronic enlarging timers used a capacitor in the timing circuit. Even some with selector switches for units and tens, thereby appearing rather "digital," are actually switching in and out various resistors used for the RC timing. The electrolytic capacitors generally used do not age well and do even worse if they don't have voltage across them for long periods. As such the value and the leakage can shift and really screw up results. This is one area where a "true digital" device might be preferrable. I repaired one of the analog timers I acquired by replacing the original capacitors with some solid tantalum units. It worked pretty well for a while, but then after a year or so started going off noticeably.

I can't say I ever do it, but I like the numbers to be legitimate readings, so that three years from now, and a new timer later, I might work from my old notes to make another print. Although I suppose there's enough other variables it's probably silly to worry.

 

[michaelbsc]

the timing is usually based on a capacitor being charged through a series of resistors, and both these components show change of precision with age, timers do show some ageing. But the important thing, as you said, is that 40 units are consistently twice the time of 20 units.

I've got one of those old Spirotone "digital" timers, and if his is anything like mine I can assure you that 40 units are not twice 20 units. It's all over the place as you switch resistors in and out with the knobs. Grime on the contacts and component drift have taken their toll.

Can I complain? No, it was free in some other box of treasures. Can I use it? No, nothing about it is consistent. Can I fix it? Sure, but who has the time.

I'm saving my pennies for one of Nicholas's F-stop timers.

 

[fschifano]

I have two GraLab and two Time-O-Lite timers. All are in good working order and are as accurate as they need to be. Voltage drifts don't bother them as long as the frequency of the AC current driving them is consistent, and yes, the power companies do make sure that that is VERY consistent. Voltage drifts don't bother my enlarger too much either thanks to a regulated power supply. Each can be set to within 1/2 second precision and that's more than good enough provided your exposure times are not ridiculously short. I also have an old Beseler "digital" timer that is notoriously finicky. Sometimes it works. Sometimes not. It came in a box with a bunch of other stuff that I rescued from the trash. I won't bother fixing it.
Time-O-Lite timers can be found on ebay for as little as $10Us, and they are simple, rugged, and dependable.