HF100G won't cancel selection pins

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

Guy's,
I agree with Rob on cleaning the keyboard. I have not tried the"floor stripper", but see no reason it should not be used --the Ajax ?? Might be OK, but might also be "gritty" enough to remove some of the silver plating from the switches ? One caution, that I think Rob forgot to mention--Remove the latch bar solenoid, and any "meter" FIRST--you do not want "liquid" of any kind in them. I use a commercial "de-greaser" followed with a rinse in warm/hot water, then I dry the keyboard and re-wash it with ammonia, followed with another clear water rinse, and a TOTAL dry prior to use. I do NOT use any type of "contact cleaner" here, as it tends to build up "short circuit paths".
As for the SA unit not starting the scan--yep--covered in the service manual--I don't know the page numbers--but it's in the trouble shooting guide, section--and, oh, BTW--NO "sprays" of any kind here !! ( I have rebuilt too many "gunked-up" SA Units !! ) Ron Rich

One caution, that I think Rob forgot to mention--Remove the latch bar solenoid, and any "meter" FIRST--you do not want "liquid" of any kind in them.

Now, there is a glaring omission on my part. However, i Do wash the solenoid and counter but take care to keep most of the stripper out of them as it can strip the doping off the coils. If ever all coils are thoroughly dry before power-up there is no problem.

if you are unsure; remove them.

Rob

Rob,
I also did not remove them for years--but I had two keyboard solenoids "burn up" shortly after I washed the keyboard, some 25-30 years ago, so I have since removed them on EVERY keyboard--- Ron Rich

HI Ron & Rob

Keybord has been cleaned and is now making the proper selections, YEAH! Now there are a few pins that do not initiate scan, pages 101-108 in Trouble Shooting Guide seem to cover this issue. For example, the A-1 pin fails to initiate scan, although if I move the pin manual several times it will then start the scan. It apparently is not making solid contact. If no sprays like Deoxit are to be used, do I need to take the pin bank apart to clean the pins> UGH UGH UGH

Best
Darrell

Hi Darrell,
Yep, basically----but first do exactly what the book says--that usually works, IF, "someone" has not "sprayed" "something", in it--
Ron Rich