Dekatron Counting Board Identification - UK Vintage Radio Repair and Restoration Discussion Forum

Sam · 23rd Apr 2005, 8:15 pm

OK, another long-shot from Sam...

I have got back to Uni and found my Dekatron Boards I bought on eBay. I was just wondering if anyone out there has any info on them.

They are plug-in printec-circuit boards, approximately 135mm x 68mm. The Dekatron is a GC10/4B / CV1739, and there is also a 12AT7 / CV4024 mounted on the board, along with a few resistors and capacitors (Hunts have gotten here too! grr

).

On the top there is the legend 'I.D.L. DRG. No. 03380/1' printed in white, and on the bottom 'TYPE 1701/A' written in copper lettering. There are 12 terminals/contacts on the bottom.

So then, any hints?! Don't expect many, if I am honest!

Sam

paulsherwin · 24th Apr 2005, 2:52 am

The GC10 decatron just needs a kick to advance one digit (represented as a dot around the viewing area). If you do a bit of googling you'll find circuits to build 'spinners' using these valves which take a triggering pulse from the normal 50Hz supply.

I'm thinking of building an EM34 replacement using these things. The idea is to use a VCO chip to generate the pulses, so as the AGC voltage changes the rate of spinning changes.

Best regards, Paul

Sam · 24th Apr 2005, 4:08 pm

Quote:

Originally Posted by paulsherwin

The GC10 decatron just needs a kick to advance one digit (represented as a dot around the viewing area). If you do a bit of googling you'll find circuits to build 'spinners' using these valves which take a triggering pulse from the normal 50Hz supply.

I'm thinking of building an EM34 replacement using these things. The idea is to use a VCO chip to generate the pulses, so as the AGC voltage changes the rate of spinning changes.

Best regards, Paul

I have a circuit about somewhere in a book I got out of the Uni library which has the driving circuits. I keep meaning to do this, but never quite get round to it. All it needs is a couple of caps to get a phase shift between the A and B guides, and a few resistors.

The Magic Eye replacement idea souds interesting! Let us all know the outcome.

Sam

jim_beacon · 1st May 2005, 10:02 pm

Sam,

I picked up a book at the NVCF today:

Digital Pulse Waveforms, Milman and Straub, 1956

which covers Dekatrons, ring counters, bistables, astables and monostables, as well as computer logic circuits, all with valves!

It is about 700 pages, so it will take me a while to sift out the relavent parts, and then I may have some useful info for you.

Jim.

PS, don't bother with the 1963 version, it had gone solid state!

Sam · 1st May 2005, 10:10 pm

Quote:

Originally Posted by jim_beacon

Sam,

I picked up a book at the NVCF today:

Digital Pulse Waveforms, Milman and Straub, 1956

which covers Dekatrons, ring counters, bistables, astables and monostables, as well as computer logic circuits, all with valves!

It is about 700 pages, so it will take me a while to sift out the relavent parts, and then I may have some useful info for you.

Jim.

PS, don't bother with the 1963 version, it had gone solid state!

I'll keep a look put for a copy of that. It sounds fun!

Once the exams are out the way, I might have to have a play and see if I can make a few of the things I have here light up.

Sam

Sam · 17th May 2005, 9:57 pm

Well, in between revision I have been trying to trace out the circuit for the board. Hard to believe it is what I am doing to keep me sane at the moment! (It's better than Signal Processing and Management revision though

)

Anyway, I think the Dekatron counting arrangement is fed from a trigger circuit. This seems plausable, as the trigger will respond to an impulse, and the trigger will then pass a pulse of a fixed voltage to the Dekatron. An output of the Dekatron can then be fed into another board, so 10s, 100s, 1,000s, etc, can be counted. I have been trying to identify the trigger circuit from one of my books. It looks like a Schmitt trigger circuit, but it seems to have too many resistors in it! I assume these are likely to be potentiometer biasing resistances. If anyone wants it, I can try and put the circuit into a neater form, and scan it.

I have found myself a copy of the book than Jim recommended, so I may be able to perform a better identification soon - when I am not revising, of course!

Any thoughts on my little deductions are more than welcome!

Sam

plumbweiss · 22nd Nov 2006, 10:54 pm

Some schools still use geiger counter / counter scalers using dekatrons, made by either Philip Harris or Griffin & George. We repair them occasionally, the last one needed a new mains tx which we manufactured. I've got the schematics somewhere.

23rd Apr 2005, 8:15 pm	#1
Sam Hexode Join Date: Apr 2003 Location: Higham-on-the-Hill, Leicestershire, UK. Posts: 338	Dekatron Counting Board Identification OK, another long-shot from Sam... I have got back to Uni and found my Dekatron Boards I bought on eBay. I was just wondering if anyone out there has any info on them. They are plug-in printec-circuit boards, approximately 135mm x 68mm. The Dekatron is a GC10/4B / CV1739, and there is also a 12AT7 / CV4024 mounted on the board, along with a few resistors and capacitors (Hunts have gotten here too! grr ). On the top there is the legend 'I.D.L. DRG. No. 03380/1' printed in white, and on the bottom 'TYPE 1701/A' written in copper lettering. There are 12 terminals/contacts on the bottom. So then, any hints?! Don't expect many, if I am honest! Sam __________________ Can he lead a Normal life, Doctor? No, he will be ... an Engineer.

24th Apr 2005, 2:52 am	#2
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,944	Re: Dekatron Counting Board Identification The GC10 decatron just needs a kick to advance one digit (represented as a dot around the viewing area). If you do a bit of googling you'll find circuits to build 'spinners' using these valves which take a triggering pulse from the normal 50Hz supply. I'm thinking of building an EM34 replacement using these things. The idea is to use a VCO chip to generate the pulses, so as the AGC voltage changes the rate of spinning changes. Best regards, Paul

1st May 2005, 10:02 pm	#4
jim_beacon Retired Dormant Member Join Date: Mar 2003 Location: Bishop's Waltham, Hants, UK. Posts: 939	Re: Dekatron Counting Board Identification Sam, I picked up a book at the NVCF today: Digital Pulse Waveforms, Milman and Straub, 1956 which covers Dekatrons, ring counters, bistables, astables and monostables, as well as computer logic circuits, all with valves! It is about 700 pages, so it will take me a while to sift out the relavent parts, and then I may have some useful info for you. Jim. PS, don't bother with the 1963 version, it had gone solid state!

17th May 2005, 9:57 pm	#6
Sam Hexode Join Date: Apr 2003 Location: Higham-on-the-Hill, Leicestershire, UK. Posts: 338	Re: Dekatron Counting Board Identification Well, in between revision I have been trying to trace out the circuit for the board. Hard to believe it is what I am doing to keep me sane at the moment! (It's better than Signal Processing and Management revision though ) Anyway, I think the Dekatron counting arrangement is fed from a trigger circuit. This seems plausable, as the trigger will respond to an impulse, and the trigger will then pass a pulse of a fixed voltage to the Dekatron. An output of the Dekatron can then be fed into another board, so 10s, 100s, 1,000s, etc, can be counted. I have been trying to identify the trigger circuit from one of my books. It looks like a Schmitt trigger circuit, but it seems to have too many resistors in it! I assume these are likely to be potentiometer biasing resistances. If anyone wants it, I can try and put the circuit into a neater form, and scan it. I have found myself a copy of the book than Jim recommended, so I may be able to perform a better identification soon - when I am not revising, of course! Any thoughts on my little deductions are more than welcome! Sam __________________ Can he lead a Normal life, Doctor? No, he will be ... an Engineer.

22nd Nov 2006, 10:54 pm	#7
plumbweiss Retired Dormant Member Join Date: Nov 2006 Location: Manchester, UK. Posts: 157	Re: Dekatron Counting Board Identification Some schools still use geiger counter / counter scalers using dekatrons, made by either Philip Harris or Griffin & George. We repair them occasionally, the last one needed a new mains tx which we manufactured. I've got the schematics somewhere.