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Post subject: CyberTwin Encoder control Cleaning
Posted: Mon Apr 18, 2016 9:28 am
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Encoders are modern controls with a click detent and the ability for continuous rotation. They are essentially a digital switch that can sense the direction of rotation.
They have been around for years, but I am just now starting to see them as a service issue.
The common symptom is erratic behavior, whether while turning the knob or just sitting there. When the switch is noisy, it’s not just scratchy analog, its digital “Garbage In, Garbage Out”. It can freak out the amp and the owner.
I know most of the DIYers out there probably won’t need this, but for more advanced tinkerers, I have good news about these modern controls. They are easy to clean.
So I had a Cyber-Twin come in a while back. It would sit there and change settings by itself. When you turn the knobs, the display changes randomly.
While it makes the amp completely unusable, the cure is a straight forward cleaning of the encoders to stabilize them.
This is new territory for me, but I was pleasantly surprised how easy it is to clean them.
I normally remove and disassemble controls to refurbish them. These encoders can be disassembled and cleaned without removing them from the board.
Image
After pulling the chassis, removal of the encoder board is next. Remove the encoder knobs and the nuts behind them.
Use colored sharpies to mark the 3 connectors. Then the mounting screws need a short Phillips to get in there.
There is a connector to the display with long pins that disconnects when the board is pulled back. Re-assembly requires paying attention to this connector and not bending pins.
Image
Image
Once the board is out, it needs to be supported with a couple staging blocks. This allows work to proceed on a flat surface without bending the aforementioned pins.
Now, I opened all the encoders at once to expedite each step. You can do them one at a time.
Using a small screwdriver, pry the 4 tabs on the encoder body. These tabs are made of soft steel and bend many times without breaking. Still, I try to only bend them enough to clear the body.
This helps with aligning the body on reassembly. Its critical to come straight down on the contacts to avoid bending them. The tabs act as an alignment guide if they are all bent back evenly.
Image
Image
Image
The contacts are coated with grease. Remove with a QTip and alcohol or plastic safe solvent. Don’t bend the contacts and confirm that all the brush contacts have even height.
The rotor contacts are usually tarnished to a yellow color. I use a fine glass brush to clean these back to a bright silvery color. The body brushes are inspected for wear and all the grease is removed. Clean the brushes carefully so as not to bend them.
Lubricate with a generous coating of lithium grease as seen on the right.
Image
Reassemble the encoders using the tabs for guiding the rotor straight down on the brushes. Push the tabs down and crimp them against the body with Channel locks as shown for a tight assembly.
Image
After surgery, this CyberTwin had its brains back in working order



.


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Post subject: Re: CyberTwin Encoder control Cleaning
Posted: Mon Apr 18, 2016 2:08 pm
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TimsA,

Thanks for a great technical post, great pictures to show what/how your doing.
I've never used a glass brush. Seems to me like a lot of grease on the contacts.
I could see using grease for the lubrication turning part of the control.
I guess the grease doesn't interfere with the actual sliding electrical contact.

Going the extra step to disassemble and clean the control, rather than replace it with a new part is the tech way to go. Hope those steal tabs don't break.


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Post subject: Re: CyberTwin Encoder control Cleaning
Posted: Mon Apr 18, 2016 4:16 pm
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Great post, especially for those that need this. You were pretty careful but this might just be a tad too difficult for anyone less than an experienced tech, having said that, have you found any issues with the solder lines? Seems to me that has the potential to be a real problem with these.

T2

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Post subject: Re: CyberTwin Encoder control Cleaning
Posted: Mon Apr 18, 2016 9:38 pm
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You can buy a glass brush, but they're rather coarse. I built these out of a fiberglass rod that makes a finer bristle. I think it was a buss support for an organ keyboard. Anyway, you set the end on fire and burn out the resin in a well ventilated area. Burn it about 1/4" down. Extinguish and crush the burnt end. Clean it with solvent and trimthe brush to length with scissors. It is useful to clean relay and switch contacts, even gold ones if you're careful.
The other end I grind a flat and cut a V to scrape tube pins clean.

Greasing it up is just following what I found in it already. Lots of grease on the contacts. This,I think, is to reduce exposure to oxygen that tarnishes the contacts.
I don't have an ID or source for original greases. The lithium grease is from the auto parts store and is rated for sliding contacts. I haven't had any problems with it.
One of the attractive aspects of cleaning these onboard is that these are double sided boards and very easy to damage if it needs removal. So an onboard service reduces the risk of a failed surgery.


I seldom replace a control. It can be very difficult and time consuming to research, locate and buy the proper vintage control. If I can service it properly and return it in a more relevant timeframe, its time well spent.
I've had it with sprays and potions. For me, they are a sure path to a warranty in 6 months with an unhappy curtomer. So disassembly, solvent, QTips and card stock clean it out properly.
I often take an entire row apart on a vintage piece and disassemble them all. I use Isopropyl 97% on new and laquer thinner on old ones.
Then inspect it for contact alignment and tension. There are some problems a spray won't touch that inspection reveals..
I use lithium grease on the sliding center ring and silicone grease on the shafts if they are disassembled. The bulb grease for automotive use is the greatest stuff to give a nice tight feel to the shaft rotation. Hmmm does that sound.... oh well.
The tabs are soft drawn steel and usually give 5-6 bends before breaking.
..


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Post subject: Re: CyberTwin Encoder control Cleaning
Posted: Tue Apr 19, 2016 12:54 am
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Thank's TimAudio, you do a great job and great pictures.


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Post subject: Re: CyberTwin Encoder control Cleaning
Posted: Tue Apr 19, 2016 6:25 am
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Excellent !
This certainly is a useful post
Lots of Cyber amps with messed up encoder dials

Thanks

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Post subject: Re: CyberTwin Encoder control Cleaning
Posted: Thu Feb 02, 2017 8:20 am
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So I wanted to let you know I followed your very helpful repair/cleaning guide and my Cyber Twin is running smoothly again (the encoders were acting erratic before). Due to restrictions in my country I used motor oil instead of the lithium grease (should be fine for the next few years). Thanks again!


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Post subject: Re: CyberTwin Encoder control Cleaning
Posted: Mon Oct 09, 2017 4:35 am
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I disassembled the CyberTwin last weekend and tried to use ancient Radio Shack Tuner Cleaner. I also used Q-tips and alcohol to clean the opened encoder of tarnish and grease. Re-assembled and it did not fix the issue. So, this weekend I went to GC and bought DeOxIt and repeated the process. What took me 2 hours to do last weekend took me only 30 minutes this weekend.

Short story long - It works perfectly now. I can access all of the settings one at a time, like it's supposed to, and it's a fun amp all over again. Sure wish I could have seen the previously posted photos so I would have had a clue first time around what I was getting into. The boards are a bit convoluted to access the screws and the standoffs properly, for an amateur, but I managed to get it back together twice, and it worked each time.


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Post subject: Re: CyberTwin Encoder control Cleaning
Posted: Mon Oct 09, 2017 12:38 pm
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Joined: Fri Feb 05, 2010 4:31 am
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Location: Province de Québec, Canada
Congrat,

You learn how cheap contact cleaner do not work.


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Post subject: Re: CyberTwin Encoder control Cleaning
Posted: Mon Oct 09, 2017 3:41 pm
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To many, the CyberTwin is a dated solid state amplifier, and I purchased mine back about 2000 from Mars Music in Nashville. At that time the price was going up to #1800 so I got a deal on the store demo unit at $1000. Today, I'd be lucky to get $350 for it on the used market. Never gigged with it, smoke-free home. But it's plenty powerful, and versatile, even though it's a First Edition, not an SE. I've had people jam on it with bass guitar, using the '59 Bassman settings, and it cooks. I am returning to my roots, wanting to have the one that got away - '64 Vibroverb BF. But I cannot afford the vintage, so maybe I'll build one from scratch.

It's just nice to have a well built modern amp, that can take an amateur poking around and fixing it.

Now I have to go and open up my other Fender - '94 Ultimate Chorus with dirty pots that make it cut out. Should be a breeze after winging it on this CT beast. Kudos for this forum and the ability to help users fix problems. Thanks. :D


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Post subject: Re: CyberTwin Encoder control Cleaning
Posted: Sat Oct 21, 2017 4:33 am
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Congrats on your encoder repair, Mark! I love your "what took me 2 hrs last week took 30 min the second time"; it's so true. When I first changed the thermal paste on my laptop it took about 3 hrs, now I can whip the thing open, do a fix and close up in 30 min like you say.

My CT has always had the cover on when not in use and the encoder has always worked great. I will have to drop the chassis sometime to replace tubes. My 2101 Is a different story... Encoder jumps all over the place...I did replace tubes in my 2101 and it sounds nicer now...I got these new tubes from
http://www.nocrotec.com/shop/index.php/cat/c2_Digitech-parts.html/XTCsid/9c75d58e8c763819226fae78a0ee1d9f

Yeah, too bad about those photos going awol in this thread; I'd love to see

_todd


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