Model M question: ?/ key is double registering?

[thatsmrdoctortoyou]

Howdy,

My Model M (part number 1391401) has an issue where the ?/ key intermittently registers twice, especially with light key strikes. Has anyone experienced this before?? <-- unintentional double question  )
Any ideas on what I should look for when I take it apart?

Potentially helpful info:
-this key does not stick or touch surrounding keys.
-it has the same feel and sound as all other keys.
-No other keys have this issue
-Screw modded by previous owner

Thanks for the help!

[klennkellon]

How many rivets are missing from your M?

[thatsmrdoctortoyou]

How many rivets are missing from your M?

Good question. It was actually screw modded by its previous owner. Would a loose rivet/screw cause keys to occasionally double register?

[Moistgun]

How many rivets are missing from your M?

Good question. It was actually screw modded by its previous owner. Would a loose rivet/screw cause keys to occasionally double register?

It could.
An overly tightened screw or bolt could also cause issues.

[thatsmrdoctortoyou]

How many rivets are missing from your M?

Good question. It was actually screw modded by its previous owner. Would a loose rivet/screw cause keys to occasionally double register?

It could.
An overly tightened screw or bolt could also cause issues.

Interesting. I'll have to take it apart this weekend and take a look. Because I have not done a screw/bolt mod before, how tight should the screws be?

[Moistgun]

I don't really know the proper tightness of them, I just did my bolts to a point I felt comfortable that they were snug, but not really pulling all that hard. Tested, and it fixed all my issues.

I would just open it and look to see if the screws are looser or tighter in that area of the board that has the issue.
Then tweak it a bit and try the key again while you still have the board opened

[thatsmrdoctortoyou]

I don't really know the proper tightness of them, I just did my bolts to a point I felt comfortable that they were snug, but not really pulling all that hard. Tested, and it fixed all my issues.

I would just open it and look to see if the screws are looser or tighter in that area of the board that has the issue.
Then tweak it a bit and try the key again while you still have the board opened

That's good advice, thank you. I'll take a look at it this weekend and report back. Maybe I'll take some pictures for reference.

[Moistgun]

Im sure there are some suggestions out there to do it a little more measured out.
Im more of the "give it a shot and deal with issues as they come up" kind of guy.

Probably the reason I have so many failures in the first place. 

Good luck and let us know!

[chyros]

How many rivets are missing from your M?

Good question. It was actually screw modded by its previous owner. Would a loose rivet/screw cause keys to occasionally double register?

It could.
An overly tightened screw or bolt could also cause issues.

Interesting. I'll have to take it apart this weekend and take a look. Because I have not done a screw/bolt mod before, how tight should the screws be?

Tight but not over-the-top.

[thatsmrdoctortoyou]

UPDATE:
-I opened up the case to check the tightness of screws running through the plate - Thanks for the advice Moistgun! The majority of the screws were tight, but didn't seem overly tight. However there are several screws running along the base of the plate which may have been overtightened at one point causing them to strip threads a bit. Below is a picture (not mine) of a model m plate with screws encircled which are stripped and do not tighten. Should I replace the screws with bolts/nuts? Problem with double registering ?/ during light keystrokes persists.

[Moistgun]

I would suggest doing bolts instead of screws because they have a much better chance of not stripping. The screw likely pulled away the plastic is was supposed to be using as an anchor point. with nuts and bolts, they are squeezing using their own mechanism, and not at grabbing the case like screws.

[thatsmrdoctortoyou]

I would suggest doing bolts instead of screws because they have a much better chance of not stripping. The screw likely pulled away the plastic is was supposed to be using as an anchor point. with nuts and bolts, they are squeezing using their own mechanism, and not at grabbing the case like screws.

Yeah I think that is what I will end up doing. Do you know by chance the bolt/nut size that work for bolt-modding?

[Moistgun]

http://www.mcmaster.com/#92005a029/=4ltsqh

http://www.mcmaster.com/#90592a004

These are what I used.

Copied a imgur post from ripster Xp

[thatsmrdoctortoyou]

http://www.mcmaster.com/#92005a029/=4ltsqh

http://www.mcmaster.com/#90592a004

These are what I used.

Copied a imgur post from ripster Xp

 )
Thanks fam

[Moistgun]

http://www.mcmaster.com/#92005a029/=4ltsqh

http://www.mcmaster.com/#90592a004

These are what I used.

Copied a imgur post from ripster Xp

 )
Thanks fam

No problem dad.
let me know if you need any helps.

[xtrafrood]

A little bit of Loctite should prevent those bolts from loosening from vibration. Once you get everything sorted from the overtightened bolts

[thatsmrdoctortoyou]

A little bit of Loctite should prevent those bolts from loosening from vibration. Once you get everything sorted from the overtightened bolts

Oh... do you think some of the screws may be overtightened?? The screw-mod was done by the previous owner and I've never done the mod before so I'm afraid I don't know how tight they should be. I opened up the board last night and found that the base row of screws were stripped, leading me to believe that could be my problem. I was going to replace that row of screws with bolts/nuts but now I'm wondering if I should loosen some of the other screws first to see if that resolves the problem.

What are your experiences with how tight the screws or bolts should be?? <<OMG it's killing me...

[xtrafrood]

A little bit of Loctite should prevent those bolts from loosening from vibration. Once you get everything sorted from the overtightened bolts

Oh... do you think some of the screws may be overtightened?? The screw-mod was done by the previous owner and I've never done the mod before so I'm afraid I don't know how tight they should be. I opened up the board last night and found that the base row of screws were stripped, leading me to believe that could be my problem. I was going to replace that row of screws with bolts/nuts but now I'm wondering if I should loosen some of the other screws first to see if that resolves the problem.

What are your experiences with how tight the screws or bolts should be?? <<OMG it's killing me...

Snug is the general rule for bolts or screws that would not cause bodily harm if they are loose. I use to apply loctite to bolts on all my skateboards and bicycles (I lived close to work). I know how vibration effects nuts/bolts over a period of time. Also: I would loosen the bolts so that they're snug. Overtightened bolts could cause warping in the long run.

I don't have a bolt modded keyboard. All I can offer is my unconventional advice