Selector Buttons Fail To Latch

Thanks Ron, will report what I find in a couple of days. Have a good weekend. My wife and I along with Mark are going to the Chicagoland show in the morning!

Best
Darrell

Ron

Finally found time to pull the back cover off. I am a little confused, as I can only find one thing that resemples a "wheel" and that is the nylon toothed gear in the upper left area and it returns to the "home" position. Where are the other "wheels" located?

I have looked at stepper contacts and ones marked NC seem to be closed.

I can get the mech to move if I manually operate the contacts on timing relays 1/2.

After manually operating all of the stepper contacts, the selector keys operated twice, as did the wom, now it is back to where I started?

Darrell

Hi Darrell,
The step-up wheels are located under the cover--the thing in the rear is the scan control unit.
If you look at the center of either "plate", with all the wires soldered to it, you will see a small hole, and a screw visible thru that hold--that screw is on the step-up wheels. Lightly turn it--one way, and it should "snap" back when you let it go. Try both wheels --just turn it slightly to check. If they are returning, I would suspect that a NC contact on one of the timing relays is not making good contact, even if it "looks good". Do you have a burnishing tool--if so, burnish the contacts, and check adjustment as per the manual.
Ron

Ron

The "wheel" on the left seems to hang up sometimes. When I tested it and got it to snap back the selctor keys performed properly. Any suggestions on how to get this wheel to loosen up? Spray with Deoxit? or Contact cleaner?

I do not have a burnishing tool and have used a thin piece of cardboard to clean contacts?

Darrrell

Darrell, the problem has two causes:

1) The small roller on the number wheel -the one you refer to, opens the contacts to the keyboard latch solenoid. That along with a set of contacts on the timing relays remove the keyboard from the selection system when stepper is operating.

My approach is to eliminate both functions as they can cause problems. The simplest solution to a gummy roller is to take a pliers and ''slightly-- bend it's mounting bracket so that the roller no longer touches the wheel. Once done the latchbar solenoid will not release while stepper is in use, but in decades of commercial use I've not found this to cause a problem. I also eliminate the contacts that transfer the write-in pulse on the timing relays, but that is probably not necessary for home use.

2) The other cause is tarnish on the stepper rivets. This forms a gummy residue and slows/stops the wheels from resetting. I remove the wafer and polish these rivets along with the moving contact (be careful not to bend the spring contact out of shape.

Rob/NYC

(Lousy typist).

Rob

Thanks for the info, should resolve problem.

Best
Darrell