trigger tube trouble jukebox [new thread]

[bob harper]

hi all, started a new thread to avoid confusion with previous postings...thanks to all who have helped previously, i am getting there! all trigger tubes are now working as expected, except one...i have 3 schematics, and this pcb falls between all 3! with bits from all of them, wired in the factory as original....i have included the part with the problem, as it resembles what is actually on the board...even then a 4.7 meg is omitted which is shown on the schematic. the problem is with GR43 [14b]

this should strike with a pulse fromER32 via 0.1 cap the 2x 22meg resistors in series [the 4m7 is ommited and directly connected] to the A of ER32. the 18 meg forms a divider. the GR43 is extinguished by a negative pulse via BY115 diode.

the problem is this tube lights up with power up when it should not...i disconnected the trigger to this tube and powered up, it remained off...i then thought i would check voltages, when the trigger tube is touched by the meter probe [measuring to ground 1000v range] it fires the tube....the rest of the cycle is correct, it is extinguished by the negative pulse and remains off

if i now reconnect the trigger, and measure the trigger voltage with the tube lit i have 80 volts to ground at the trigger but only 11 volts at the other end of the 22meg so it appears the tube is giving out 80 volts on its trigger [is this right?] i expected it to be zero with the tube lit?

any help with this gratefully received....with hopefully this last fault!  bob

[bob harper]

i just noticed a mistake, it is extinguished by a positive pulse, not negative as i stated above  bob