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+--- Thread: 65: Slight squeaks from the card reader (/thread-14336.html)
65: Slight squeaks from the card reader - Dave Britten - 01-08-2020 08:09 PM
The card reader in my 65 (thanks Don!) is working just fine, but it's developed a little bit of a squeak. I'm not shy about opening it up to clean/lubricate parts, but I don't really know where to begin with the mechanics of it all. I know there's some kind of clutch that could be slipping, plus a worm gear driving a gear wheel on the card transport roller. The actual card transport speed seems normal and steady, so it's not having any obvious difficulty advancing the cards. And it reads and writes perfectly fine.
Any tips on what I should try? My fear is that the squeak indicates something might be subjected to more wear than it should be from normal use.
RE: 65: Slight squeaks from the card reader - rprosperi - 01-08-2020 11:12 PM
(01-08-2020 08:09 PM)Dave Britten Wrote: The card reader in my 65 (thanks Don!) is working just fine, but it's developed a little bit of a squeak. I'm not shy about opening it up to clean/lubricate parts, but I don't really know where to begin with the mechanics of it all. I know there's some kind of clutch that could be slipping, plus a worm gear driving a gear wheel on the card transport roller. The actual card transport speed seems normal and steady, so it's not having any obvious difficulty advancing the cards. And it reads and writes perfectly fine.
Any tips on what I should try? My fear is that the squeak indicates something might be subjected to more wear than it should be from normal use.
Earplugs?
Really, I own 65s, 67s and 41 card readers and nearly all of them have squeaked or squealed a bit from time to time, but it has never gotten worse and sometimes it (the noise) stops completely. It's actually quite interesting what a wide variation in sounds these readers make, given the similarity of the designs.
Unless it starts to get noticeably louder or worse, or starts to mis-read, I would not open the machine to 'oil it' just because of the noise.
OTOH, I don't really use my card readers a lot, probably once a year or so as I cycle through my machines to check on them, charge batteries, etc. So frequent users may have better advice.
RE: 65: Slight squeaks from the card reader - teenix - 01-09-2020 12:04 AM
(01-08-2020 08:09 PM)Dave Britten Wrote: The card reader in my 65 (thanks Don!) is working just fine, but it's developed a little bit of a squeak. I'm not shy about opening it up to clean/lubricate parts, but I don't really know where to begin with the mechanics of it all. I know there's some kind of clutch that could be slipping, plus a worm gear driving a gear wheel on the card transport roller. The actual card transport speed seems normal and steady, so it's not having any obvious difficulty advancing the cards. And it reads and writes perfectly fine.
Any tips on what I should try? My fear is that the squeak indicates something might be subjected to more wear than it should be from normal use.
It is more likely that the aging motor has worn rotor shaft bearings which can "rattle" when in use. The motor spins at 10,000 or so RPM so that rattle manifests itself as a high frequency squeal.
I don't know if it is fixable other than motor replacement.
cheers
Tony
RE: 65: Slight squeaks from the card reader - burkhard - 01-09-2020 02:12 PM
Quote:I know there's some kind of clutch that could be slipping,
There is no clutch in any of the 41/65/67 card readers. Somebody said that long ago and for some reason it has stuck, but it's quite incorrect. What people call the "clutch" is the motor output shaft, a coupler, which rather than being completely rigid, has an elastomeric bit in its middle between two metal ends. The idea of such of coupler is to slightly dampen out the pulsations in the motor output drive.
The elastomer in that shaft, like that in the infamous drive wheel, can fail over time which can result in slippage from one side of the shaft to the other. Such slippage *might* be why people call it a clutch, but that's a mistake. It's not supposed to disengage, slip, and re-engage (like a clutch would). When the coupler in the card reader does that, it has failed. Geoff Quickfall has a video on YouTube that nicely shows how he has done a repair. He uses electric wire insulation as a new elastomer. People might squirm thinking that is not the exact specification as the original elastomer and while they are probably right, I suspect the tolerance of what "works plenty fine" is pretty broad.
In any event, the "squeak" you hear might be that coupler starting to give up the ghost. Is the squeaking happening in concert with a jerking feed of the card into the reader? If the shaft is slipping, that will be reflected in the card motion. Personally, I probably would live with a little noise unless it fails completely or you had reason to open the calculator for other reasons.
RE: 65: Slight squeaks from the card reader - Dave Britten - 01-09-2020 02:24 PM
(01-09-2020 02:12 PM)burkhard Wrote: There is no clutch in any of the 41/65/67 card readers. Somebody said that long ago and for some reason it has stuck, but it's quite incorrect. What people call the "clutch" is the motor output shaft, a coupler, which rather than being completely rigid, has an elastomeric bit in its middle between two metal ends. The idea of such of coupler is to slightly dampen out the pulsations in the motor output drive.
The elastomer in that shaft, like that in the infamous drive wheel, can fail over time which can result in slippage from one side of the shaft to the other. Such slippage *might* be why people call it a clutch, but that's a mistake. It's not supposed to disengage, slip, and re-engage (like a clutch would). When the coupler in the card reader does that, it has failed. Geoff Quickfall has a video on YouTube that nicely shows how he has done a repair. He uses electric wire insulation as a new elastomer. People might squirm thinking that is not the exact specification as the original elastomer and while they are probably right, I suspect the tolerance of what "works plenty fine" is pretty broad.
In any event, the "squeak" you hear might be that coupler starting to give up the ghost. Is the squeaking happening in concert with a jerking feed of the card into the reader? If the shaft is slipping, that will be reflected in the card motion. Personally, I probably would live with a little noise unless it fails completely or you had reason to open the calculator for other reasons.
Ah, I see, thanks for clarifying. I'll see if I can dig up Geoff's video.
The card motion is nice and smooth, with no evidence of jerking or slip on the coupling, so it's probably just a bit more noise from the motor, or maybe even something else that's a bit loose inside the case vibrating along with the motor. The noise is perfectly livable, I just want to be sure it doesn't mean that something is out of whack and going to cause premature failure somewhere in the drivetrain.
I did open it up already to clean all the key contacts (and the key response is absolutely beautiful now), so I'm not afraid to go in again if there's something else that needs a small tweak.
RE: 65: Slight squeaks from the card reader - wallyt - 01-09-2020 03:25 PM
Hello, in my own experience I have found that the squeaks were caused by the slipping of the elastomeric coupler (aka clutch). Once I repaired that part all was quiet again. It is a bit of a job to do, however there is plenty of good information on this site to accomplish the task.
RE: 65: Slight squeaks from the card reader - Harald - 01-09-2020 03:52 PM
On the card readers I looked at the most common cause of noise was friction of the worm gear shaft where it rotates in the plastic part oposite the motor. A tiny bit of lubricant on that point and the noise is gone.
RE: 65: Slight squeaks from the card reader - Dave Britten - 01-09-2020 04:23 PM
(01-09-2020 03:52 PM)Harald Wrote: On the card readers I looked at the most common cause of noise was friction of the worm gear shaft where it rotates in the plastic part oposite the motor. A tiny bit of lubricant on that point and the noise is gone.
If that's all it needs, then that's a cinch. Just to make sure I understand correctly, you're talking about the fixed end of the worm gear furthest from the motor, and not where the worm gear meshes with the elastomeric coupling, right?
What kind of lubricant would be best/safest to apply there?
RE: 65: Slight squeaks from the card reader - Dave Britten - 01-09-2020 07:54 PM
(01-09-2020 03:52 PM)Harald Wrote: On the card readers I looked at the most common cause of noise was friction of the worm gear shaft where it rotates in the plastic part oposite the motor. A tiny bit of lubricant on that point and the noise is gone.
I think that may have been it! I picked up some Labelle 108 light synthetic oil (advertised as "plastic compatible") at the hobby shop, worked a very tiny drop into both sides of the fixed plastic mount at the right end of the worm gear, and so far it's back to a nice soft hum.
Now, since I have the oil, is there anything else that should be lubricated preventively? The motor itself, the interface between the worm gear and gear on the transport roller, etc.? Or is it better to just leave it all be?
RE: 65: Slight squeaks from the card reader - teenix - 01-10-2020 05:22 AM
(01-09-2020 03:52 PM)Harald Wrote: On the card readers I looked at the most common cause of noise was friction of the worm gear shaft where it rotates in the plastic part oposite the motor. A tiny bit of lubricant on that point and the noise is gone.
I never would have thought of that, considering the very small contact area.
cheers
Tony