Beseler 8177 Timer Help

[Baisao]

I just purchased a used Beseler 8177 Audible/Repeating Enlarging Timer. Either the thing is broken or I don't know how it works (possible since I don't have a manual for it).


The left dial is marked 1-10. The right dial is marked in tenths. There is a switch beneath these for 1x and 10x.


Logically, if I select 1x and turn the left dial to 2 I will get two chirps. However, if I select 10x and move the dial to 2, it doesn't seem to stop chirping (tested past two minutes).


I've tried selecting 10x, 0, .4 and it just keeps going (I assumed this would have been 4 or perhaps 40 seconds).


Can someone explain how this works so I can test it properly?


Thanks in advance!

 

[TheTrailTog]

This is the same timer I use. The 10x will multiply whatever your combination of dial settings is by 10. So for your "10x, 0, .4" should equal 4 seconds. Honestly though, never used the 10x option. I do 3 (3, 0) second intervals for my initial test print, then adjust to compensate for dry down in my final prints (usually 2, .8).

 

[Baisao]

Thanks for elaborating.

So you are doing three 3 second exposures (3,0)? Also, would 10x, 3, 0 equate to 30 seconds? If so, it is broken.

 

[TheTrailTog]

I do 3 second intervals. For example, one of the prints I worked on today needed a 15 second base exposure so I did five 3-second exposures. I didn't have anyone to teach me, so I learned from watching the old Fred Picker videos and that was what he did. Yes, 10x, 3, 0 should equal 30 seconds.

 

[Baisao]

Thank you, sir!

 

[TheTrailTog]

You get it working?

 

[Baisao]

No, it's busted. I wasn't sure how it operated but your explanation confirmed that I had it right and it was broken. I'm returning to seller. There's virtually no documentation on it so I really appreciate your assistance.

 

[gleaf]

If I remember the insides rightly the internals are Resistors and Capacitors which are switched in controlling the rates of 3 timing circuits. Two are in 556 dual timer chip and one is a 555 chip. Last one repaired had a bad section in the 556 chip.

 

[Hilo]

I do 3 second intervals. For example, one of the prints I worked on today needed a 15 second base exposure so I did five 3-second exposures. I didn't have anyone to teach me, so I learned from watching the old Fred Picker videos and that was what he did. Yes, 10x, 3, 0 should equal 30 seconds.

Sorry to change the original post, but pressing the timer 5 times to reach a 15 second exposure time is not ideal. While exposing you want to quietly look at your projected negative, you want to think about possibilities how to improve . . . exposing is one of the purest moments in the life of the printer, with all respect you do not want to be busy pushing the button all the time . . .

 

[Baisao]

If I remember the insides rightly the internals are Resistors and Capacitors which are switched in controlling the rates of 3 timing circuits. Two are in 556 dual timer chip and one is a 555 chip. Last one repaired had a bad section in the 556 chip.

Would I be able to test these with a multimeter? I assume I would be testing for continuity in each of the three circuits to see which one needs replacing. I've never soldered a board but I'm not averse to trying.

 

[sfaber17]

I have the same 8177 and am familiar with those circuits. I'll fix it for you for the cost of shipping it back to you if you want. It may save time over trying to go back and forth with emails measuring voltages.

 

[TheTrailTog]

Sorry to change the original post, but pressing the timer 5 times to reach a 15 second exposure time is not ideal. While exposing you want to quietly look at your projected negative, you want to think about possibilities how to improve . . . exposing is one of the purest moments in the life of the printer, with all respect you do not want to be busy pushing the button all the time . . .

Different folks, different strokes. Without anyone to learn from first hand, I learned from watching the Fred Picker Zone VI videos...

https://www.youtube.com/watch?v=fYiGa4T120Q

This was the method he used and it works well for me. I don't find the repeated pressing of the expose button to detract at all from the experience. I prefer to have loud music playing and I prefer to look for what areas need improvement after looking at a developed print rather trying to discern during exposure.

 

[sfaber17]

Yes, I found cases where I was using f11 at 14 sec and then found exposure was best at 13.5 sec, but you can't do it with those 2 digit timers, so you either have to flip to f8 and use 6.7 sec or if you want to keep f11, then you need to do the multiple exposures. Guess that is why I never use those 2 digit timers.

 

[CropDusterMan]

I have the same 8177 and am familiar with those circuits. I'll fix it for you for the cost of shipping it back to you if you want. It may save time over trying to go back and forth with emails measuring voltages.

Man, that is such a nice offer from sfaber17...great example of community.

 

[sfaber17]

I looked at mine and it looks like the 556 had been replaced also, so it might be best to replace that first yourself per gleaf. Note the orientation of the chip first then cut all the leads near the chip and pull it out leaving the leads. Then use your iron to desolder while pulling each lead in turn. Next use a wood toothpick while heating each pad in turn to open up the holes. You can get the chips cheap on ebay and some had sockets with them, which would be a good idea while you are at it. Solder in the socket and put the chip in with the right orientation and give it a try.

 

[Baisao]

I'll fix it for you for the cost of shipping it back to you if you want. It may save time over trying to go back and forth with emails measuring voltages.

Yes, that truly is an amazing offer! I may take you up on it. However, I really enjoy DIY. I grew-up on a farm and we made everything ourselves. I frequently offer to fix my friends cameras for free. It gives me something productive to do, that I enjoy, in the evenings. If you don't mind answering questions should they arise then I would love to do it myself.

I looked at mine and it looks like the 556 had been replaced also, so it might be best to replace that first yourself per gleaf. Note the orientation of the chip first then cut all the leads near the chip and pull it out leaving the leads. Then use your iron to desolder while pulling each lead in turn. Next use a wood toothpick while heating each pad in turn to open up the holes. You can get the chips cheap on ebay and some had sockets with them, which would be a good idea while you are at it. Solder in the socket and put the chip in with the right orientation and give it a try.

Great advice! I'll give that a try.

The seller gave me a refund and let me keep the busted one. I was glad because I sure didn't want to pay shipping on a worthless brick. I didn't think it could be fixed, so...

I picked-up a second one and it mostly works. The times are slow on 1x, specifically 1x/10/0 will either go on forever or go for 13 seconds <-- one or the other. 1x/9/0 goes for 11 seconds. 1x/8/0 goes for 8 seconds. All times at 10x are spot on.

It was sold used but was new in box. The cord was still braided from the factory. It seems odd that it would behave erratically yet be new from the factory. Maybe the contacts are oxidized?

 

[DWThomas]

It was sold used but was new in box. The cord was still braided from the factory. It seems odd that it would behave erratically yet be new from the factory. Maybe the contacts are oxidized?

Oxidized contacts are one possibility, but the timers that used 555/556 chips depended on a resistor-capacitor ("RC") combination to set timing. At the slow speeds needed for enlarger timing, the capacitors may be electrolytics which deteriorate over time, and in fact may degrade worse if they are not electrically charged (think photoflash capacitors on a smaller scale). The range of timing needed also points toward some relatively high value resistors where leakage across the surface of a cheap circuit board could screw up timing also. Thirty years ago 555 timers were everywhere, but if I were going to build my own timer today I would be looking at some sort of digital micro-controller.

 

[sfaber17]

I may have spoken too soon on the 556. I was looking at mine more (I was familiar with the chips, not this particular unit), I figured that it wasn't going to work at all if the 556 is blown. So it may be more likely the switch or dirty pot, or the capacitor idea per DW. Usually an old capacitor is more likely than ICs to go bad but in this case the power supply is dropped right off the mains with a resistor, which could lead to things happening that could blow the chips more easily. Also be careful when you are working on it! There is another thread where the circuit was discussed and analyzed that would be worth looking up, since it shows you how to adjust the pots that control the timing.

 

[sfaber17]

Agreed. A long time ago I was trying to make a timer from 555s but I had trouble with the long times due to the leakage and the high value resistors.

 

[sfaber17]

Maybe the contacts are oxidized?

Yes. I'd get some Deoxit contact cleaner. There is one for gold and one for non-gold. Get the non-gold.
Then spray the contacts but be gentle and don't over do it when working the controls back and forth.

 

[Baisao]

The Deoxit is expensive but I'll try to source some. It's worth a try.

Perhaps this is more of a historical question but why are the controls (seemingly) unnecessarily elaborate: 1x/10x, 1-10, 0.0-1.0? In other words, why didn't so many of these timers work like a clock where you directly enter, say, 50 seconds and it counts up to that and turns off? It seems to a lay person like myself that the tech to do this was available since the mid-70s.

 

[DWThomas]

It is most likely a question of parts and manufacturing cost, plus the beast is essentially an analog device and it would be difficult to get the combination of timing range and resolution. It might have been done in those days with small scale digital parts, but it would have been a bag full of them -- remember 8" floppy disk drives had a large circuit board full of dozens of chips and sold for $250 to $500 back in the late 1970s. We are lucky and maybe a bit spoiled by the technology we're surrounded by today!

 

[sfaber17]

Here are some more details on the circuit. The 556 has 2 timers, the first half times the beeps the second times the enlarger relay. Both halves work for both x1 and x10 mode. The x1/x10 switch switches the threshold lead 12 to capacitor C6 for x10 mode or C7 for x1 mode. The other segment of the switch connects R7 (variable resistor= potentiometer or pot. for short) to the control voltage pin 11 in x10 mode or R10 in x1 mode. When the start button is pushed, current charges the selected capacitor through resistors determined by the rotary selectors. The voltage on the capacitor ramps up with time and when it reaches the control voltage on pin 11, the output 9 is toggled which controls the relay. In my unit, C6 and C7 are blue and tan teardrop shaped capacitors. They look like tantalum caps. which are high quality low leakage caps. that don't go bad with time like aluminum electrolytics can.
You could then put your meter (assuming it is a multimeter with high input impedance) on pin 12 (tied to 13 also) and ground (pin7 or a point around the edge of the board). Start timing and see if the voltage ramps up. Also see if you have a reasonable voltage on pin 11. Mine is 6.1 volts. If the voltage does ramp up but doesn't reach the threshold, then there may be leakage.
If it isn't ramping at all, then maybe the slide switch has problems. Anyway that should help in debugging.

 

[M Carter]

I have the same 8177 and am familiar with those circuits. I'll fix it for you for the cost of shipping it back to you if you want. It may save time over trying to go back and forth with emails measuring voltages.

This forum has restored my faith in humanity on a regular basis.

An additional note - I'm guessing this is the same timer as the Omega CT-20?

Another note - that proprietary foot switch? Go to a music store and get a cheap momentary keyboard/effect foot switch - the kind with a long cable and a 1/4" TS male (IE a guitar-style plug). They're cheap. Then grab a 1/4" TS female panel jack, a buck or two.

Open the case, desolder the footswitch leads (even the 3-prong jacks only have 2 leads), find a spot to drill a hole for the new jack, and solder it up. I really, really love having the foot switch - most of the time it sits near my baseboard and I flick it with my hand. For really complex dodging with a mask, I stick it on the floor and use my foot. Super-crazy-handy!

 

[Baisao]

Here are some more details on the circuit...

This doesn't make sense to me but thank you for taking the time to write this out for those that do. I will have to look up some of the terms but it sounds like a fun afternoon project. I love learning and I'm sure there are others who will come upon this and find your diagnostic description useful.

Thank you!