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A Way to (Sometimes) Repair Broken 22xx Knobs

Philip McIntosh All Messages By This Member #87700 Well here is my first actual contribution to the group. I had to learn the hard way what most of you probably already know--NEVER REMOVE THE KNOBS FROM A 2200 SERIES SCOPE UNLESS YOU ABSOLUTELY HAVE TO. I figured it would be easier to clean the front panel with the knobs removed (and it is) but I have experienced about a 50% breakage rate when removing the small knobs along the top and for the trigger. They are old and brittle. As has been pointed out, they are hard to find and not cheap when you do find them (although I was fortunate enough to talk a guy on eBay into selling me a lot of them for a pretty reasonable price). So, I have been experimenting with ways to rescue the broken ones. What generally happens is one side of the little plastic retainer clip on the inside snaps off. One thing I have tried is drilling out an HP knob that looks exactly the same and figuring out how to secure it (these are available by the bushel for cheap at a local surplus store). No luck on that so far, but that is for another time. What does mostly work is cutting a little piece of plastic tubing in the shape of the missing piece and sliding it into position with tweezers. It works best if the clip is completely broken off flush, but that is rare, so you have to cut the tubing to account for what ever part of the clip remains. The tubing I use is the flexible, clear plastic polyethylene Tygon type with an OD of 5/16in and a wall thickness of 1/64in. They seem to pop back on pretty well. There is ever so slight an eccentricity when they turn but you'd really have to know what you were looking for to notice it. I think it might even work better if the entire clip was missing and you might try removing it with a small grinding tool. Trying to break off the clip or remaining pieces has resulted in complete destruction of the knob. Let me know if you come up with any improvements or better ways to rescue a knob.
DaveC #87701 A photo would be great. Dave Sent from my iPhone toggle quoted message Show quoted text On Feb 17, 2013, at 8:46 AM, "Philip" <ndpmcintosh@...> wrote: Well here is my first actual contribution to the group. I had to learn the hard way what most of you probably already know--NEVER REMOVE THE KNOBS FROM A 2200 SERIES SCOPE UNLESS YOU ABSOLUTELY HAVE TO. I figured it would be easier to clean the front panel with the knobs removed (and it is) but I have experienced about a 50% breakage rate when removing the small knobs along the top and for the trigger. They are old and brittle. As has been pointed out, they are hard to find and not cheap when you do find them (although I was fortunate enough to talk a guy on eBay into selling me a lot of them for a pretty reasonable price). So, I have been experimenting with ways to rescue the broken ones. What generally happens is one side of the little plastic retainer clip on the inside snaps off. One thing I have tried is drilling out an HP knob that looks exactly the same and figuring out how to secure it (these are available by the bushel for cheap at a local surplus store). No luck on that so far, but that is for another time. What does mostly work is cutting a little piece of plastic tubing in the shape of the missing piece and sliding it into position with tweezers. It works best if the clip is completely broken off flush, but that is rare, so you have to cut the tubing to account for what ever part of the clip remains. The tubing I use is the flexible, clear plastic polyethylene Tygon type with an OD of 5/16in and a wall thickness of 1/64in. They seem to pop back on pretty well. There is ever so slight an eccentricity when they turn but you'd really have to know what you were looking for to notice it. I think it might even work better if the entire clip was missing and you might try removing it with a small grinding tool. Trying to break off the clip or remaining pieces has resulted in complete destruction of the knob. Let me know if you come up with any improvements or better ways to rescue a knob. ------------------------------------ Yahoo! Groups Links
Tom Miller Member Profile All Messages By This Member #87702 开云体育 Hello Philip, ? Please let me add to your comment a way to remove the knob caps that I find works. ? As you say, they are old and brittle and prone to having the clips break off when pulled off. I take a hot air (de)soldering gun and use it to heat the knob enough to make it somewhat soft. Then I use a long pair of needle nose pliers to slip under the knob where I can pop it off easily. You will need to find the proper amount of heat to get this to work. I set mine up for 120 °C with the smallest nozzle that came with the gun (about 1/4 inch dia). ? HTH, Tom ? ? ? ? toggle quoted message Show quoted text ----- Original Message ----- From: Philip To: TekScopes@... Sent: Sunday, February 17, 2013 11:46 AM Subject: [TekScopes] A Way to (Sometimes) Repair Broken 22xx Knobs ? Well here is my first actual contribution to the group. I had to learn the hard way what most of you probably already know--NEVER REMOVE THE KNOBS FROM A 2200 SERIES SCOPE UNLESS YOU ABSOLUTELY HAVE TO. I figured it would be easier to clean the front panel with the knobs removed (and it is) but I have experienced about a 50% breakage rate when removing the small knobs along the top and for the trigger. They are old and brittle. As has been pointed out, they are hard to find and not cheap when you do find them (although I was fortunate enough to talk a guy on eBay into selling me a lot of them for a pretty reasonable price). So, I have been experimenting with ways to rescue the broken ones. What generally happens is one side of the little plastic retainer clip on the inside snaps off. One thing I have tried is drilling out an HP knob that looks exactly the same and figuring out how to secure it (these are available by the bushel for cheap at a local surplus store). No luck on that so far, but that is for another time. What does mostly work is cutting a little piece of plastic tubing in the shape of the missing piece and sliding it into position with tweezers. It works best if the clip is completely broken off flush, but that is rare, so you have to cut the tubing to account for what ever part of the clip remains. The tubing I use is the flexible, clear plastic polyethylene Tygon type with an OD of 5/16in and a wall thickness of 1/64in. They seem to pop back on pretty well. There is ever so slight an eccentricity when they turn but you'd really have to know what you were looking for to notice it. I think it might even work better if the entire clip was missing and you might try removing it with a small grinding tool. Trying to break off the clip or remaining pieces has resulted in complete destruction of the knob. Let me know if you come up with any improvements or better ways to rescue a knob.
ROLYNN PRECHTL K7DFW All Messages By This Member #87703 What generally happens is one side of the little plastic retainer clip on the inside snaps off. ================================= And a drop of Super Glue will fix the broken piece back into position. Fixed-done. Rolynn
Philip McIntosh All Messages By This Member #87704 I tried super glue. Maybe my superglue is too old or something, but it just snapped right back off again. That is why I looked for a method that allowed for more flexibility and less rigidity. Phil... toggle quoted message Show quoted text --- In TekScopes@..., "ROLYNN PRECHTL K7DFW" <k7dfw@...> wrote: What generally happens is one side of the little plastic retainer clip on the inside snaps off. ================================= And a drop of Super Glue will fix the broken piece back into position. Fixed-done. Rolynn
Philip McIntosh All Messages By This Member #87706 Great tip. I thought of that but was not too sure about hitting the front panel with a hot air gun. Since I do have a hot air station with adjustable temperature, I will try that. Thanks! Phil... * toggle quoted message Show quoted text --- In TekScopes@..., "Tom Miller" <tmiller11147@...> wrote: Hello Philip, Please let me add to your comment a way to remove the knob caps that I find works. As you say, they are old and brittle and prone to having the clips break off when pulled off. I take a hot air (de)soldering gun and use it to heat the knob enough to make it somewhat soft...
Tom Miller Member Profile All Messages By This Member #87707 开云体育 I use RTV sillycone. Just a dab in the bottom of the knob then push it on. Let cure for a day and you are all set. Benefit is you can still pull the knob off in the future. ? ? Regards, Tom ? ? toggle quoted message Show quoted text ----- Original Message ----- From: Philip To: TekScopes@... Sent: Sunday, February 17, 2013 12:07 PM Subject: [TekScopes] Re: A Way to (Sometimes) Repair Broken 22xx Knobs ? I tried super glue. Maybe my superglue is too old or something, but it just snapped right back off again. That is why I looked for a method that allowed for more flexibility and less rigidity. Phil... --- In TekScopes@..., "ROLYNN PRECHTL K7DFW" wrote: > > > What generally happens is one side of the little plastic retainer clip on the inside snaps off. > > ================================= > > And a drop of Super Glue will fix the broken piece back into position. > > Fixed-done. > > > > Rolynn >
ROLYNN PRECHTL K7DFW All Messages By This Member #87708 I tried super glue. Maybe my superglue is too old or something, but it just snapped right back off again. =============================== Try giving them a long rest before replacement to assure the full cure. I usually set them aside and give them 24 hours. Haven't had a failure yet. Rolynn
Jim #87709 I've used E6000, a soft vinyl-based adhesive, with good success on re-gluing buttons. I'm not sure which I prefer, clear silicone or E6000. ?You should have some iof both in your kit. 73 Jim N6OTQ toggle quoted message Show quoted text From: Tom Miller To: TekScopes@... Sent: Sunday, February 17, 2013 11:15 AM Subject: Re: [TekScopes] Re: A Way to (Sometimes) Repair Broken 22xx Knobs I use RTV sillycone. Just a dab in the bottom of the knob then push it on. Let cure for a day and you are all set. Benefit is you can still pull the knob off in the future. ? ? Regards, Tom
Tom Miller Member Profile All Messages By This Member #87710 开云体育 I'll check that out. Thanks. ? Tom ? toggle quoted message Show quoted text ----- Original Message ----- From: Jim To: TekScopes@... Sent: Sunday, February 17, 2013 12:17 PM Subject: Re: [TekScopes] Re: A Way to (Sometimes) Repair Broken 22xx Knobs ? I've used E6000, a soft vinyl-based adhesive, with good success on re-gluing buttons. I'm not sure which I prefer, clear silicone or E6000. ?You should have some iof both in your kit. 73 Jim N6OTQ From: Tom Miller <tmiller11147@...> To: TekScopes@... Sent: Sunday, February 17, 2013 11:15 AM Subject: Re: [TekScopes] Re: A Way to (Sometimes) Repair Broken 22xx Knobs I use RTV sillycone. Just a dab in the bottom of the knob then push it on. Let cure for a day and you are all set. Benefit is you can still pull the knob off in the future. ? ? Regards, Tom
Philip McIntosh All Messages By This Member #87714 So you mean you just blob on a small dab and push it on wet so it molds to the shape of the insert? Neat trick. Phil... toggle quoted message Show quoted text --- In TekScopes@..., "Tom Miller" <tmiller11147@...> wrote: I use RTV sillycone. Just a dab in the bottom of the knob then push it on. Let cure for a day and you are all set. Benefit is you can still pull the knob off in the future.

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