SoloInterface Posted March 20, 2015 Share Posted March 20, 2015 I've got an old Oberheim Expander that works. -- It's an old school sweet machine but with glitches -- figure its time for a little contact cleaner. I have it apart. Big ICs. Rotary encoders are a 'can do' but, for the buttons, do the caps come off if I pull harder or do I put in new ones. Ugg! There a million of'm. Any suggestions? There are three kinds of musicians, those who can count and those who can't. Link to comment Share on other sites More sharing options...
Al Coda Posted March 20, 2015 Share Posted March 20, 2015 Xpantastic is the group you should join. All answers and help there ! A.C. Link to comment Share on other sites More sharing options...
Legatoboy Posted March 20, 2015 Share Posted March 20, 2015 it's a great ax... I believe the caps will pull off gently on the edges with a butter knife . .try a loose one! CP-50, YC 73, FP-80, PX5-S, NE-5d61, Kurzweil SP6, XK-3, CX-3, Hammond XK-3, Yamaha YUX Upright, '66 B3/Leslie 145/122 Link to comment Share on other sites More sharing options...
SoloInterface Posted March 20, 2015 Author Share Posted March 20, 2015 The caps come off the rotaries well enough, I'm talking about the caps (hats) on the buttons (momentary switches). Evidently they use rubber as springs inside. What is a good contact cleaner that won't harm rubber? // Thanks for the Xpantastic rec. Not much action there at the moment. Checked history but nothing on button hats. Wait'n on permission to join the forum. There are three kinds of musicians, those who can count and those who can't. Link to comment Share on other sites More sharing options...
Legatoboy Posted March 21, 2015 Share Posted March 21, 2015 I was talking about the buttons , I had one or two loose that could be pried off w/ fingers as I recall ...and pressed back on...can't comment on the cleaner to use! CP-50, YC 73, FP-80, PX5-S, NE-5d61, Kurzweil SP6, XK-3, CX-3, Hammond XK-3, Yamaha YUX Upright, '66 B3/Leslie 145/122 Link to comment Share on other sites More sharing options...
SoloInterface Posted March 21, 2015 Author Share Posted March 21, 2015 Legatoboy is right! With a little more than normal courage the hats to the Oberheim Expander's momentary buttons or switches do come off. Underneath there is a copper tang which serves as both contact and spring and it pops out too. Careful. They're tiny and they pop out like a crickets on steroids. Visual inspection shows that they do need burnishing. Since the spring is not plastic or rubber, no need to worry about sparce use of contact cleaner. I have heard (V-sauce probably) that the large percentage of the dust one sees in a sunbeam is human skin flake -- real small dandruff but not necessarily from the head. This seems to be some of what is in the way of the worst case switches. Will check the encoders too. I'll let this forum how it went when done. Ataboy Legatoboy. Thanks. There are three kinds of musicians, those who can count and those who can't. Link to comment Share on other sites More sharing options...
Brettymike Posted March 21, 2015 Share Posted March 21, 2015 I read the fine print on my can of CRC Air Flow Sensor cleaner , and there are no warnings concerning rubber (or anything else). And it evaporates so quickly, it wouldn't get half a chance to effect rubber I would think. Brett Link to comment Share on other sites More sharing options...
Al Coda Posted March 22, 2015 Share Posted March 22, 2015 Legatoboy is right! I simply replaced all the tact switches. It´s easy because the originals are from "Marquard" and the pin compatible replacements are too. Only drawback when replacing the switches, you have to buy new "hats" too, but all printings are available, the numbers, + / - and the red/organge store button as well. I myself found the parts in 2012 and posted in "Xpantastic" ... You´ll find the links for parts also in the XPLORER Forum A.C. Link to comment Share on other sites More sharing options...
SoloInterface Posted April 13, 2015 Author Share Posted April 13, 2015 Hi. Promised to get back. Success!! You can definitely do it yourself. Burnishing all the 'tact' (thanks Al Coda) switches with an exacto knife brought back a 35 year old expander to near perfect. I used a little CRC contact cleaner to top things off. The rotary encoders jump around a bit. Took about 6 hours. I am so happy! I'm midi(ed) to a Roland FP 80 and Nord Drawbar, all blow'n through dual Leslie system 21s and dig'n in. With the right ideas, the OE sounds great through Leslies. By the way, has anyone had a problem with the system 21 stuttering when changing from tremolo to choral at some settings? Has the mk2 release fixed that? Also, is the rotary encoder 'jumping around' problem fixable by replacing the 'smoothing' capacitors? There are three kinds of musicians, those who can count and those who can't. Link to comment Share on other sites More sharing options...
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