Greiner Electronic Chronografic watch timing machine restoration - UK Vintage Radio Repair and Restoration Discussion Forum

Uncle Bulgaria · 28th Oct 2022, 1:02 am

I'm working my way through one of these beautifully made machines, in the hope of returning it to working order. I have a few questions.

The principle is that a sensitive microphone clips onto the watch or clock, and the timing machine prints a series of dots on a roll of paper. Deviations in the dots can diagnose problems with the clockwork.

There is a quartz oscillator, PL5727 thyratron, ECL82, ECC85 and ECC83. I'm hazy on the operation of thyratrons, despite reading the Wikipedia article, but I surmise it's used as an oscillator to drive a stepper motor that feeds the paper at the movement's advertised rate (various beats per minute values can be selected with a knob to suit different movements).

I have replaced all the paper capacitors, which all tested leaky on removal, as well as small electrolytics. The twist-lock filter/reservoir cans seem OK.

I have tested the chassis and it sits happily without any undue current draw and normal HT.

Problems

The motor doesn't run. I guess it should on switch on. There's a paper-drive switch which engages two rollers to grip the paper and feed it, shorting the earphone sockets together at the same time. Two wires feed the stepper motor. These wires show HT and a couple of volts of AC, which doesn't seem right. The two wires to the motor show about 1k ohms so the coils are not o/c.
There's a polystyrene capacitor in series with the earphone socket and the ECC83 anode marked 5000k. I think I should change this to a modern Y2 type as failure will see HT on the earphone.

I've started drawing out the circuit around the chassis plug to the motor assembly, but it's jolly tricky.

Terry_VK5TM · 28th Oct 2022, 4:08 am

I know nothing about these but, is it possible the motor doesn't run until the microphone is connected and a ticking timepiece can be heard?

TonyDuell · 28th Oct 2022, 4:53 am

I have a Vibrograph B100 timing machine which possibly uses the same principle. The valves are somewhat similar, there are 1 or 2 power pentodes and a thyratron in mine along with some small signal valves.

The basic idea is that the crystal oscillator is divided down using monostables (fewer valves than a flip-flop divider chain but of course it can drift and give the wrong division ratio) and feeds the power pentode. This drives the synchronous motor so that the speed is effectively determined by the crystal oscillator. The 'ticks per minute' switches control the monostbles and thus the division ratio.

The motor drives a roller with a coarse helical 'thread' on it, it's also geared down to move the paper. That helix is under the paper, there's an ink ribbon and hammer bar on top, the hammer bar is operated by a solenoid and is the full width of the paper. When it operates it puts a dot on the paper at the intersection of the hammer and the helical thread.

The ticks from the microphone are amplified (more of the valves) and trigger the thyratron. This operates the hammer solenoid.

It works a bit like a stroboscope. If the ticks are timed correctly, the intersection of helix and hammer will form a line of dots straight down the paper. It the watch is running slow, the line with slope one way, if it's running fast it slopes the other way. The microphone stand is adjustable to allow 'timing in positions' -- wear in the balance wheel pivots in the watch can cause it to run slow if you hold it a particular way up, you might need to check for that.

My guess is that in your unit the pentode of the ECL82 is the motor driver. I'd check round there first, is the valve good, are the electrode voltages sane, is there a signal on the control grid.

TonyDuell · 28th Oct 2022, 8:52 am

I realise it can't be the same instrument (the valve line-up is different for one thing) but here's a circuit diagram I reverse-engineered of my Vibrograf unit some years ago. It'll give an idea of the stages and sort of circuitry involved.

Note that the HT+ circuit is completed via the front panel switches, something that confused me at a quick glance this morning.

Uncle Bulgaria · 28th Oct 2022, 10:25 am

Thank you very much for the ideas everyone! The idea that microphone 'ticks' are needed to actually trigger the thyratron is a good one. I've not rewired the input lead yet so will try that before I go any further. I was confused as in the same lot of machines I got another Vibrograf of a different design with a Pabst motor that runs when the machine's switched on.

Thank you for the circuit description, TonyDuell. I'll look up monostables with the (probably necessary) coffee. Maybe there's one of those old Navy videos available with a sharp-jawed man telling me about it in clipped tones with stop-motion animation. My favourite teaching aid. I can see I'm going to have a collection of your circuit diagrams as you've got the reverse-engineering skill! (I'm just waiting for some film capacitors before attacking the Contamination Meter) - splitting the circuits up is a good idea. I was having a lot of trouble peering beneath the carefully lashed together components to find the layered wiring. Goodness knows what these cost when new, or how many Swiss hours were taken over hand-wiring them so conscientiously.

Here's a beautiful Vibrograf VS 390 circuit plate from m0cemdave (5Y3, 2050, 6SL7, 5692, 2x 6SN7 & 6F6) that shows yet another model. As he suggested to me, they all seem very similar in conception and I can see the thyratron, double triode etc. in that.

What are the thoughts about the earphone capacitor?

TonyDuell · 28th Oct 2022, 11:15 am

I am pretty sure the motor should run without 'ticks', there may be a 'start' button on the panel of course. The 'ticks' fire the hammer solenoid and actually put a dot on the paper.

Robsradio · 28th Oct 2022, 4:04 pm

The motor is not self starting and needs to be spun to start. Switch it on and leave for 30 seconds then spin it. As for ticks, they are only activated when the paper pinch roller is lowered to draw the paper through.

Uncle Bulgaria · 28th Oct 2022, 8:23 pm

Thanks both. I see that if it isn't self-starting, that could be why the knurled wheel on the spindle has an arrow engraved in it. I had cleaned and greased the gunked motor bearings previously, but still it doesn't turn.

Turning it by hand without the unit on, there is a strong magnetic field that makes the spindle stop in certain positions. Doing this with the unit on, there is an accompanying hum and sense of force, but not enough to make the spindle spin. I have checked for undue friction, but everything's greased and with the barrel with the coils in removed, the spindle can spin freely.

My other (unrestored) Chronografic has a motor that spins for a few revolutions when started with a finger spin on the knurled wheel, quickly settling to one of the stepper positions. It does spin though, and moves more freely. Perhaps I need to reduce friction further on this one that isn't turning, or increase the amplitude of the motor signal.

Is HT with a couple of volts of AC (perhaps even ripple) what one would expect?

Uncle Bulgaria · 29th Oct 2022, 8:21 pm

I've been using the circuit diagrams I've kindly been sent to correlate information around the oscillator. Here's where I've got to with the triode section of the ECL82.

The quartz crystal is a grey painted tube with a 7-pin valve base. Marked 5940 Hz Y50212. The components are as shown in the attached diagram. The variable capacitor is marked C005 AA/25E. The hollow dogbone capacitor in parallel with it has the colour bands green brown green brown black.

The attached consistent, even waveform is detected between the crystal and the 100R grid resistor. At x10, 0.2V/div and 50µs/div, I make that 12Vp-p at 588Hz.

I can't find an exact analogue of the oscillator circuit in my "Radio Handbook", but that looks like a healthy waveform so far, doesn't it?

Uncle Bulgaria · 1st Nov 2022, 10:09 pm

A little more brain sweat equity has resulted in the attached diagram. I apologise in advance for the poor layout. My reverse engineering skills are in their infancy.

I believe the motor is in need of pulses to get it to run. The first oscilloscope trace shows the ECL82 gT signal (~23Vpk), while the aP is the second (~170vpk).

I haven't progressed beyond the ECC85 grid as the only wire off the pin is a thin one that goes to what I presume is a transformer, coupling to the next valve. I will need to unsolder the leads to work out what's what.

Uncle Bulgaria · 9th Nov 2022, 8:14 pm

I've removed a motor of the same design from the other unit mentioned in post #8 and plugged it in to the one where I've replaced the waxie capacitors. The motor spins once started, so there must be excess friction in the original motor despite my cleaning and regreasing the bearings. I guess I need to check the spindle for straightness...

roadster541 · 8th Jan 2023, 5:22 pm

I have finally dug out a circuit diagram. It may be too late, but I am sure that it will be of help to someone.
I will attach it as a PDF. There is just one diagram plus a blank page, which is just something that happened when scanning.
Rod

28th Oct 2022, 1:02 am	#1
Uncle Bulgaria Nonode Join Date: May 2016 Location: Cornwall, UK. Posts: 2,333	Greiner Electronic Chronografic watch timing machine restoration I'm working my way through one of these beautifully made machines, in the hope of returning it to working order. I have a few questions. The principle is that a sensitive microphone clips onto the watch or clock, and the timing machine prints a series of dots on a roll of paper. Deviations in the dots can diagnose problems with the clockwork. There is a quartz oscillator, PL5727 thyratron, ECL82, ECC85 and ECC83. I'm hazy on the operation of thyratrons, despite reading the Wikipedia article, but I surmise it's used as an oscillator to drive a stepper motor that feeds the paper at the movement's advertised rate (various beats per minute values can be selected with a knob to suit different movements). I have replaced all the paper capacitors, which all tested leaky on removal, as well as small electrolytics. The twist-lock filter/reservoir cans seem OK. I have tested the chassis and it sits happily without any undue current draw and normal HT. Problems The motor doesn't run. I guess it should on switch on. There's a paper-drive switch which engages two rollers to grip the paper and feed it, shorting the earphone sockets together at the same time. Two wires feed the stepper motor. These wires show HT and a couple of volts of AC, which doesn't seem right. The two wires to the motor show about 1k ohms so the coils are not o/c. There's a polystyrene capacitor in series with the earphone socket and the ECC83 anode marked 5000k. I think I should change this to a modern Y2 type as failure will see HT on the earphone. I've started drawing out the circuit around the chassis plug to the motor assembly, but it's jolly tricky. Attached Thumbnails

28th Oct 2022, 4:08 am	#2
Terry_VK5TM Nonode Join Date: Oct 2010 Location: Tintinara, South Australia, Australia Posts: 2,339	Re: Greiner Electronic Chronografic watch timing machine restoration I know nothing about these but, is it possible the motor doesn't run until the microphone is connected and a ticking timepiece can be heard? __________________ Terry VK5TM https://www.vk5tm.com/

28th Oct 2022, 4:53 am	#3
TonyDuell Dekatron Join Date: Jun 2015 Location: Biggin Hill, London, UK. Posts: 5,208	Re: Greiner Electronic Chronografic watch timing machine restoration I have a Vibrograph B100 timing machine which possibly uses the same principle. The valves are somewhat similar, there are 1 or 2 power pentodes and a thyratron in mine along with some small signal valves. The basic idea is that the crystal oscillator is divided down using monostables (fewer valves than a flip-flop divider chain but of course it can drift and give the wrong division ratio) and feeds the power pentode. This drives the synchronous motor so that the speed is effectively determined by the crystal oscillator. The 'ticks per minute' switches control the monostbles and thus the division ratio. The motor drives a roller with a coarse helical 'thread' on it, it's also geared down to move the paper. That helix is under the paper, there's an ink ribbon and hammer bar on top, the hammer bar is operated by a solenoid and is the full width of the paper. When it operates it puts a dot on the paper at the intersection of the hammer and the helical thread. The ticks from the microphone are amplified (more of the valves) and trigger the thyratron. This operates the hammer solenoid. It works a bit like a stroboscope. If the ticks are timed correctly, the intersection of helix and hammer will form a line of dots straight down the paper. It the watch is running slow, the line with slope one way, if it's running fast it slopes the other way. The microphone stand is adjustable to allow 'timing in positions' -- wear in the balance wheel pivots in the watch can cause it to run slow if you hold it a particular way up, you might need to check for that. My guess is that in your unit the pentode of the ECL82 is the motor driver. I'd check round there first, is the valve good, are the electrode voltages sane, is there a signal on the control grid.

28th Oct 2022, 11:15 am	#6
TonyDuell Dekatron Join Date: Jun 2015 Location: Biggin Hill, London, UK. Posts: 5,208	Re: Greiner Electronic Chronografic watch timing machine restoration I am pretty sure the motor should run without 'ticks', there may be a 'start' button on the panel of course. The 'ticks' fire the hammer solenoid and actually put a dot on the paper.

28th Oct 2022, 4:04 pm	#7
Robsradio Heptode Join Date: Nov 2010 Location: Isle of Wight, UK. Posts: 557	Re: Greiner Electronic Chronografic watch timing machine restoration The motor is not self starting and needs to be spun to start. Switch it on and leave for 30 seconds then spin it. As for ticks, they are only activated when the paper pinch roller is lowered to draw the paper through.

28th Oct 2022, 8:23 pm	#8
Uncle Bulgaria Nonode Join Date: May 2016 Location: Cornwall, UK. Posts: 2,333	Re: Greiner Electronic Chronografic watch timing machine restoration Thanks both. I see that if it isn't self-starting, that could be why the knurled wheel on the spindle has an arrow engraved in it. I had cleaned and greased the gunked motor bearings previously, but still it doesn't turn. Turning it by hand without the unit on, there is a strong magnetic field that makes the spindle stop in certain positions. Doing this with the unit on, there is an accompanying hum and sense of force, but not enough to make the spindle spin. I have checked for undue friction, but everything's greased and with the barrel with the coils in removed, the spindle can spin freely. My other (unrestored) Chronografic has a motor that spins for a few revolutions when started with a finger spin on the knurled wheel, quickly settling to one of the stepper positions. It does spin though, and moves more freely. Perhaps I need to reduce friction further on this one that isn't turning, or increase the amplitude of the motor signal. Is HT with a couple of volts of AC (perhaps even ripple) what one would expect?

29th Oct 2022, 8:21 pm	#9
Uncle Bulgaria Nonode Join Date: May 2016 Location: Cornwall, UK. Posts: 2,333	Re: Greiner Electronic Chronografic watch timing machine restoration I've been using the circuit diagrams I've kindly been sent to correlate information around the oscillator. Here's where I've got to with the triode section of the ECL82. The quartz crystal is a grey painted tube with a 7-pin valve base. Marked 5940 Hz Y50212. The components are as shown in the attached diagram. The variable capacitor is marked C005 AA/25E. The hollow dogbone capacitor in parallel with it has the colour bands green brown green brown black. The attached consistent, even waveform is detected between the crystal and the 100R grid resistor. At x10, 0.2V/div and 50µs/div, I make that 12Vp-p at 588Hz. I can't find an exact analogue of the oscillator circuit in my "Radio Handbook", but that looks like a healthy waveform so far, doesn't it? Attached Thumbnails

1st Nov 2022, 10:09 pm	#10
Uncle Bulgaria Nonode Join Date: May 2016 Location: Cornwall, UK. Posts: 2,333	Re: Greiner Electronic Chronografic watch timing machine restoration A little more brain sweat equity has resulted in the attached diagram. I apologise in advance for the poor layout. My reverse engineering skills are in their infancy. I believe the motor is in need of pulses to get it to run. The first oscilloscope trace shows the ECL82 gT signal (~23Vpk), while the aP is the second (~170vpk). I haven't progressed beyond the ECC85 grid as the only wire off the pin is a thin one that goes to what I presume is a transformer, coupling to the next valve. I will need to unsolder the leads to work out what's what. Attached Thumbnails

9th Nov 2022, 8:14 pm	#11
Uncle Bulgaria Nonode Join Date: May 2016 Location: Cornwall, UK. Posts: 2,333	Re: Greiner Electronic Chronografic watch timing machine restoration I've removed a motor of the same design from the other unit mentioned in post #8 and plugged it in to the one where I've replaced the waxie capacitors. The motor spins once started, so there must be excess friction in the original motor despite my cleaning and regreasing the bearings. I guess I need to check the spindle for straightness...