Discussion:
Game Paddles vs Joystick - faulty paddles?
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p***@gmail.com
2017-09-26 04:33:53 UTC
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Hi,
I am new to game paddles (vs. joystick) the Apple II, I just picked up a pair from eBay. Here is what I am seeing:

10 POKE -16295,0
20 PRINT PDL(0)
30 GOTO 20

When I run this and rotate the paddle, it seems to work as expected EXCEPT - when the paddle is in motion, PDL() function often (not always) returns 255. So I might see values scroll by for example:

100
101
100
100
255
104
104
104
255

The same code used with joystick works exactly as expected (w/o the 255 values).

I assume there is no "software" for this... but I'd love to be wrong.

Are these just noisy paddles that are worn out/defective.... fixable?

Thanks,
Paul
Michael J. Mahon
2017-09-26 06:13:30 UTC
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Post by p***@gmail.com
Hi,
I am new to game paddles (vs. joystick) the Apple II, I just picked up a
10 POKE -16295,0
20 PRINT PDL(0)
30 GOTO 20
When I run this and rotate the paddle, it seems to work as expected
EXCEPT - when the paddle is in motion, PDL() function often (not always)
100
101
100
100
255
104
104
104
255
The same code used with joystick works exactly as expected (w/o the 255 values).
I assume there is no "software" for this... but I'd love to be wrong.
Are these just noisy paddles that are worn out/defective.... fixable?
Thanks,
Paul
Yes, those are "noisy" paddles, and they are likely to be easily fixed.

Inexpensive potentiometers, whether carbon or wirewound, get dirty if
unused for long periods due to contact oxidation and/or literal dirt.

Frequently they can be cleaned simply by rotating them back and forth many
times (think several dozen to start, more if still malfunctioning). If
this doesn't solve the problem after over a hundred rotations, then the
application of control cleaner may be required.

Cleaning solution for volume (and other) controls can be obtained at
electronic supply houses. Don't take chances with rubbing alcohol or other
cleaners, because 1) they may remove the thin carbon film, ruining the pot,
and 2) control cleaner contains a small amount of lubricant which is
beneficial to the pot.

But always try repeated operation first. It's very likely to be sufficient.


The problem may recur if the control is not regularly used, but that's
won't be a problem if you are using them!

BTW, what's the purpose of the POKE to $C059? Is there some reason to set
AN1? No preparation is needed to use PDL().
--
-michael - NadaNet 3.1 and AppleCrate II: http://michaeljmahon.com
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