Re: HF100G won't cancel selection pins
Posted: Tue Jul 08, 2014 1:24 pm
Mark, my approach for cleaning keyboards in wallboxes for the last 28 years has been: Use 50% diluted floor stripper in a spray bottle with warm-hot water. thoroughly wet the keyboard, then sprinkle some scouring cleanser (A-jax etc) into the contacts and work them in-out. The idea is to clean any tarnish off the sliders. Rinse thoroughly with hot water while working the switches again and blow dry with a strong source of warm air. I use a 1980's Electrolux vac with a clean hose and crevice tool as blower. I've never needed to repeat the process to get zero ohms across the contacts. You might add a -light- coating of contact cleaner-lube afterwards though I don't believe Ron agrees with this step.
When you look at the keyboard contacts you'll notice that there is a feed-through set of contacts. These are to prevent getting more than one selection at a time by pressing two or more buttons. These contacts carry the write-in pulse and if enough resistance builds up it can cause erratic failure to punch the desired pin. A thorough washing should eliminate any problems here.
From what I recall, the 25VAC selection pulse first enters the keyboard via the round plug on the credit unit, goes through five of the number buttons ( it looks like 10 and 10, but it really is 15 and 5) hops across to the pin memory unit. The purpose of plugging the Jones into the WSR is to parallel with the Stepper contacts.
Failure of some selected pins to initiate scan is not a matter of adjustment. It is a matter of cleaning. When a pin is punched a small washer around it's stem slides to a buss plate and grounds the plate which completes the Play Control relay's circuit. Rust and crud can foul this up. If all other pins work and you don't want to disassemble the memory unit (I don't blame you) try squirting a little contact cleaner up into the defective pin openings and manually working them . That may be adequate to get them going.
Rob/NYC
When you look at the keyboard contacts you'll notice that there is a feed-through set of contacts. These are to prevent getting more than one selection at a time by pressing two or more buttons. These contacts carry the write-in pulse and if enough resistance builds up it can cause erratic failure to punch the desired pin. A thorough washing should eliminate any problems here.
From what I recall, the 25VAC selection pulse first enters the keyboard via the round plug on the credit unit, goes through five of the number buttons ( it looks like 10 and 10, but it really is 15 and 5) hops across to the pin memory unit. The purpose of plugging the Jones into the WSR is to parallel with the Stepper contacts.
Failure of some selected pins to initiate scan is not a matter of adjustment. It is a matter of cleaning. When a pin is punched a small washer around it's stem slides to a buss plate and grounds the plate which completes the Play Control relay's circuit. Rust and crud can foul this up. If all other pins work and you don't want to disassemble the memory unit (I don't blame you) try squirting a little contact cleaner up into the defective pin openings and manually working them . That may be adequate to get them going.
Rob/NYC
