R75 key bounce

[GB46]

Do any of the R75 owners out there get key bounce on the radio's numeric keypad and/or its up and down arrows? I do quite frequently, so that I make frequent errors keying in a frequency or assigning a name to identify it with.

As for the up and down arrows, often I'll be scanning my memory slots by hand one keystroke at a time and suddenly notice I've skipped over one. For example, trying to go from #85 to #86 will sometimes put me on #87; same goes for navigating downward.

None of these problems is consistent, however, and it doesn't always happen on the same key. I can often get more accuracy by being much quicker in releasing the key after each keystroke, so it's more like tapping the key than pressing it. This is not a roll-over effect; the same problem doesn''t occur if I hold the key down. In fact, if I hold one of the arrow keys down, it will scan through all of the memory slots without skipping any of them.

I can't remember if the radio was always this way, because I only took it out of storage and started using it again over the past year. Since I bought it brand new in 2000, prior damage is unlikely.

 

[ka3jjz]

While damage is unlikely, dirt and grime from sitting so long getting into the keypad is a possibility.

If you don't get any answers here, there appears to be a fairly active Yahoo group for this radio where help is likely at hand...

https://groups.yahoo.com/neo/groups/icomr75/info

Mike

 

[GB46]

Thanks, Mike. I used to belong to that group a very long time ago. That's where I downloaded the R75 service manual -- not that I could understand the circuitry, but it was interesting to see the complexity of that radio.

I'll see what I can do about cleaning those keys non-invasively. Contact cleaner is definitely out. That was how I screwed up my laptop's keyboard when trying to fix a problem with the down-arrow key. It was the only faulty key, but the spray made the problem worse, to the point that it disabled some other keys and the computer also started responding to invalid and repeated key presses when I hadn't even touched any keys. I had to disable the laptop keyboard entirely and substitute a wireless keyboard. "Live and learn," as my mother was fond of saying.

 

[ridgescan]

I get this like crazy on my r71a, but never on my r75 which I've owned since 2008. With the r71a, I find that hitting the keys gently off-center either side completely solves it. Miles I guess. Maybe this may work on yours?

 

[GB46]

I get this like crazy on my r71a, but never on my r75 which I've owned since 2008. With the r71a, I find that hitting the keys gently off-center either side completely solves it. Miles I guess. Maybe this may work on yours?

Actually, I've already tried that, and it does help, as does a lighter and quicker touch, but it shouldn't be necessary on a receiver of this quality. Also, hitting the keys off center will sometimes result in a press of the adjacent key (my hands are of average size, but the buttons are pretty close together).The number 7 on the keypad appears to be the worst offender. I was thinking maybe the buttons are misaligned somehow; perhaps that's a design flaw that has been inherited from your R71a. My R75 was new in 2000, so the problem might have been alleviated in later releases.

 

[ridgescan]

Actually, I've already tried that, and it does help, as does a lighter and quicker touch, but it shouldn't be necessary on a receiver of this quality. Also, hitting the keys off center will sometimes result in a press of the adjacent key (my hands are of average size, but the buttons are pretty close together).The number 7 on the keypad appears to be the worst offender. I was thinking maybe the buttons are misaligned somehow; perhaps that's a design flaw that has been inherited from your R71a. My R75 was new in 2000, so the problem might have been alleviated in later releases.

I wonder if the keypad's backmount has become loose inside? This happened to my BC785D scanner's pad and it was a matter of re-tightening the nuts. Not sure about the r75.

 

[GB46]

I wonder if the keypad's backmount has become loose inside? This happened to my BC785D scanner's pad and it was a matter of re-tightening the nuts. Not sure about the r75.

Looking in the service manual at the exploded internal diagram of the face plate, I can see that the pad assembly is mounted on a plate labeled "logic unit". Behind the plate are four screws pointed at holes in this plate from behind it. No nuts are shown, and the back of the pad assembly is not shown, either, so I can't tell which of those screws, if any, would be fastened to the keypad. I can't see why the screws would have come loose, anyway, as the receiver has never been used roughly (I tend to baby my equipment).

At any rate, I'm not going to monkey around inside the radio. I had to when I installed the DSP module, when I changed the clock battery and also when I had to replace the internal fuse due to a power surge, but that was enough tampering for me (no idiot-serviceable parts inside).

It reminds me of when my brother took the back off his portable tube-type AM radio back in the early 1960s. A label inside read "for export only". I misread that, and told him, "See, it says for expert only, so you shouldn't be tampering with it." :lol: