Wall Box Issues

Hi Friends, My Wall Box for the HF100R is doing the following. The Wall Box fails to play any selection, until I select the K-9 or K-10, It then plays the K-9 or K-10 and all other selections afterwards. What's up with this? Thanks---Preston--Syracuse NY..

Hi Preston,
Either you or the "wall-box" has been taking too many drugs !
Are the pins for all other selections being "pulled", and the mech is scanning past pulled pins, or are the pins not pulling till after you play K9-0 ?
Ron Rich

Hi Ron, No drugs here Ron. When the selections are made the pins are not pulled. However when k-0 is selected, that's works fine and all the selections after work as well. ---Preston---

Preston,
My advise then, is to take drugs--doing so may solve this problem ? --
Have you watched the stepper operate--are both letter and number coils being pulsed, when it fails ?
Has the stepper been rebuilt lately--new caps installed? Is the 2050 good ?

Preston, this is one of the quirks of both the 2050 and that particular circuit.

If the tube is marginal, the cathode will be 'excited" by being made to conduct, in this case it is by a long train of pulses.

The large 5mfd cap is another typical failure point which can cause erratic miscounts.

If the small sets of contacts that ride the letter stepper clapper are not making reliably the transfer relay or the hold magnet will not be energized. Similarly, the time constant capacitor for the hold magnet must be good or the hold magnet will jitter and fall out during the transfer interval.

If contacts on the two timing relays are not in good condition, this same symptoms you describe will occur.

The first step is to remove the stepper cover and observe the step wheels in operation.

Rob/NYC