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The Stec Records Forum  |  Audio Gear  |  JamMan  |  JamMan (original)  |  Can you tell me where to get replacement encoders for a Jam Man? « previous next »
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Author Topic: Can you tell me where to get replacement encoders for a Jam Man?  (Read 8310 times)
bsellon
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« Reply #8 on: June 17, 2014, 11:49:28 AM »

Keith sent me a possible replacement encoder for the JamMan a while back which I finally got around to checking against one of the existing parts and I believe it will work as a replacement in the JamMan. The part is:

CTS 288-S0084

I got an inquiry about this recently. This is my reply:
-------------------
I haven't actually installed it in a JamMan yet but I checked the codes that the pins generate against a part from a JamMan or Reflex and it matches.  I just did a quick google search and didn't find any parts but this is a pretty good lead. The part uses a serrated knob but otherwise looks identical.

If you have a midi rig you can also use our Enhancement ROM to disable the encoders and set the mode via continuous controller.  We also have a version of the Enhancement ROM that defaults to the encoders being disabled (JamMan has no persistent memory).  You can order that here.

If you always use the JamMan in the same mode, you can also just hard wire the encoder for that mode.  You figure out where the wires should go by measuring the resistance between the center and side pins on the encoder.  When the encoders fail, the "on" resistance goes up a little bit. Instead of being just a couple of ohms they start creeping up to the point where the part reading the signals starts seeing lows as highs or vis-versa.  The nice thing about this fix is that you don't have to remove the encoder, just keep it in the target position and add little wires to the bottom of the board.

Another possible fix that I haven't yet tested is to play with the pull up/down (I forget which) resistors that are used with the encoders.  The existing encoders may work with a higher resistor value. The pull up/down resistors effectively create a resistor ladder with the switch since its ON position is not quite zero ohms. Unfortunately, a resistor pack is used making it more difficult to try values.  The transition value is very close though so it might even be possible to just add another apposing resistor/resistor pack to the encoder wires to nudge them up/down.   There is usually one contact that is bad on the encoder so you might just check the resistance of each bit/pin and look for one with a higher ON resistance.


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bsellon
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« Reply #7 on: August 27, 2012, 09:34:15 AM »

from Tito: The replacement of LXP style encoders: your suggestion: http://www.stecrecords.com/?RecordId=398 can't work properly. It has to by an inverted graycode encoder. Circuit can be modded to accept the Standard Graycode though otherwise position and value do not correspond. best, Tito

Bob: Thanks. I'll update the record.

Toto: I used a standard GRAYCODE switch  (ELMA) sometimes Grayhill and reversed the circuit. I made some notes, not too clear, but maybe helpful. The common pin of the switch has to goto +5V and the pulldown resistors have to be routed to GND.
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bsellon
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« Reply #6 on: March 02, 2010, 11:39:27 PM »

Hey M,
Bad news:  I don't have any replacement encoders.
Good news: The encoder is just switches that short the pins together in different ways. If it's the encoder on the right that broke, you can try shorting the pins in different ways to "hard-wire" the JamMan for a specific mode . When you find a mode you like, solder a small piece of wire across the pins.

If the encoder near the display broke you may be stuck. That one increments and decrements a value so it's not as easy to fake out. It may still be worth trying to short some pins on that as well.

Be sure not to touch any pins except the encoder pins.

Also be VERY careful about static. Handle the board by the edges.

I don't know if you saw them but you can find the schematics here:
http://www.stecrecords.com/index.php?RecordId=443

To remove the old encoder, heat the front pins and push the encoder up. Then do the same with the back. Back and forth.  Some times you have to actually add new solder in to get the heat to spread out. Eventually you work the encoder out.

Desoldering the encoders doesn't seem to work. You can never get all the solder out.

Also, the encoder is usually damaged when it's removed from the board so you cannot take an encoder from another unit and move it (I tried and ended up with 2 bad encoders).

You should sign up for the encoder thread on the forum so you'll be notified if there is any news on that front.
http://stecrecords.com/smf/index.php?topic=56.0

This topic has info on the "search for replacement encoders" mission:
http://stecrecords.com/smf/index.php?topic=3.0

I hope this helps.
Best regards,
Bob
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bsellon
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« Reply #5 on: March 02, 2010, 11:27:46 PM »

Hello Bob,
 
I am a fanatic and french user of the Lexicon Jamman! Unfortunately, my Jamman suffered of a big bug: it switch alone to a bizarre function mode ( the number "1" disappeared when I switched On the Looper in echo mode). Thank to the forums, it appears that it came from the rotary encoder 4 bits grey ( witch permit to change the number of beat). I wanted to changed it, I put in out ( sorry for my English language...), and I don't know how I did, but I broke a piece of the encoder... I tried to buy one, as the one showed on forum, but it is out of stock, and this piece seams to not exist again. So my jamman is completely unavailable. I would like to know if you had some rotary encoder grey 4 bits to sell to me? Or I would like to know if you had a solution for me?
 
Thank you bob for your help.
 
Yours faithfully.
 
M
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« Reply #4 on: August 05, 2006, 10:09:16 AM »

Hi Steve, Does sound like an encoder failure. Check with Jim Fabiano at www.JimFabiano.com for parts/repair. Let me know if Jim can't help you out. Also note that I've been working with a buddy on converting Lexicon Reflexs into JamMen and we have some in stock. Bob
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« Reply #3 on: August 05, 2006, 10:08:58 AM »

(yet another inquiry for encoders - Bob) Hi, I am pretty sure that the encoder has failed on my Jamman. The unit does not operate properly in echo mode and powering up into the user diagnostics, I cannot select different test numbers by turning the decoder knob. Can you tell me what the encoder's manufacturer and part number are and maybe where i can get one? It would save me the time of opening the unit. How responsive is this kind of problem to cleaning the encoder? Thanks for any info Steve DeJesus
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« Reply #2 on: August 05, 2006, 10:08:49 AM »

In your Freeking out JamMan you talk of replacing the encoder I too have the problem but where can I buy a new encoder? I live in the UK to make it even trickier Thanks a lot Ian
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« Reply #1 on: August 05, 2006, 10:08:09 AM »

Can you tell me where to get replacement encoders for a Jam Man? Thanks a bunch.
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The Stec Records Forum  |  Audio Gear  |  JamMan  |  JamMan (original)  |  Can you tell me where to get replacement encoders for a Jam Man? « previous next »
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