Hi Bob, Thanks for clarifying which trigger tube you meant.
Having looked at the circuit and also at the datasheets for the ER32 and GR44 I think that you will have to adjust the value of the 16uF capacitor and the 150k resistor as they are used for the quenching of the trigger tube, however I don't know how you should change them, but you will have to make sure that you don't lower the 150K resistor too much as that limits the current through the trigger tube. The important thing with the 150k resistor and 16uF capacitor is that they need to have the correct value to make sure that the tube is fully quenched so that it won't re-ignite by itself. You could also try to lower the 22M resistor from the trigger to the common ground to say 10M to see if that helps in keeping the trigger stable. I think it will be safe to lower the 150k resistor to say 100k and you should also be able to raise the 16uF capacitor to 32uF and even lower it to 8uF without much adverse effect on the trigger tube, but measuring the current in the circuit by hooking up a scope across the 150k resistor to see the peak voltage will give you a good look at what current flows in the circuit - don't forget to use an isolating transformer for the scope so you don't make a ground loop shorting the circuit! Are you absolutely sure that the circuit diagram is correct around the ER32, there could be something that is not drawn as it is connected in real life. And photos, as John K says will help a lot in trying to locate faults. /Martin On Friday, 28 March 2014 10:57:09 UTC+1, bob harper wrote: > > hhih<https://lh3.googleusercontent.com/-97nhgqmMh6s/UzVFZv17YiI/AAAAAAAAABM/Bu7tQ9-WTgo/s1600/canteen046-001.jpg> > > hi martin, yes i am watching the GR43 on ebay! > > yes the 1st tube on the left i was referring to is marked ER32 [sorry > thought schematic was posted up] it now has a GR44 installed in place [i > have tried a couple] the fault has now been traced to the fact that the > cathode connection to the solenoid is via a phenolic track on a pcb with a > motor driven wiper arm carrying the connection this if momentarily loses > continuity[the track is 50 years old] is enough to fire the GR44 and the > solenoid...a capacitor has been suggested across the solenoid, which i have > yet to try...bob > On Friday, March 28, 2014 9:37:07 AM UTC, Dekatron42 wrote: >> >> Hi Bob, >> >> There is a GR43 for sale on Ebay UK here: >> http://www.ebay.co.uk/itm/GR43-VALVE-SUB-MINIATURE-GAS-TRIGGER-TUBE-CERBERUS-NEW-OLD-STOCK-/251484552167?pt=UK_Sound_Vision_Valves_Vacuum_Tubes&hash=item3a8da5bbe7, >> maybe that seller has more if you need. >> >> I am sorry but I don't understand which of the trigger tubes you mean by >> the "1st tube on the left" - what number is written close to the trigger >> tube? >> >> /Martin >> >> On Thursday, 27 March 2014 09:04:33 UTC+1, bob harper wrote: >>> >>> hi all...well i have finally got this thing working...all trigger tubes, >>> in the selection system the countdown tubes in the credit unit and the 3 >>> digital display nixie tubes...but ONE remaining problem. the 1st tube on >>> the left in the schematic a GR44 [i have tried another as well] fires when >>> it should, but also when it should not, i disconnected the trigger and it >>> still fires...the problem [i think] is that the K cathode is connected via >>> a wiper contact on a rotating arm to the reset solenoid, which although >>> cleaned and adjusted and tested with the meter, must be occasionally losing >>> its contact [bear in mind the etched track is 50 years old] for a split >>> second...which i am assuming [here my knowledge gets hazy] that would allow >>> the anode voltage to rise and trigger the tube? if this is the case, is >>> there a solution to this? if not, my thought was to put in a relay which >>> when the motor driving the rotating arm is running it opens the circuit >>> from the cathode to the reset coil...any thoughts anyone? thanks, bob >>> >>> >>> >> > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com. To post to this group, send an email to neonixie-l@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/7094cf7c-df9a-4baf-a39f-57eb7ffd1011%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
