Chroma Polaris, RIP

[donaldcrunk]

wow when i unpack from the move this is the first thing i'll be on. my ribbons are super crispy still but if they can just be swapped out entirely i might be good to go, i think my membranes are fine...

 

if i can't salvage it to the point of operation, do you need any replacement parts puppy? might as well get SOME use out of the thing.

[donaldcrunk]

btw

 

http://www.youtube.com/watch?v=6Wwiz_-avng

 

 

that's how its operated now. i've gotten better with my jumping between contacts since those days (i've got a mirror!), but let that demonstrate how the rhodes chroma polaris can be used entirely without an interface

[flattop]

As Grimaila states, you want those switches to be momentaries. I want to make sure that didn't pass you by.

 

Though I appreciate the kudos, I think someone else provided the Cantos link. I don't want to steal their thunder.

[ElectricPuppy]

Oops! You're right Wes, it was mate_stubb that suggested Cantos. Sorry about that, Mate! Yes, I realize that they need to be momentary switches. I know enough 'lectricaliity to know the different switch styles. Now if only I can figure out where I can get some more oscillator fluid, I might be able to keep this thing in tune when it's finally fixed! :poke:

 

Scenic: How many beers did you have before that was shot?

[LWG]

Hello,

 

FWIW, you may want to check with ChipForBrains. He's done a run of replacement membranes for the Moog Source and the Sequential Ckts P-600.

If there were enough interest from a group of Polaris users, he may consider doing a run of replacement parts/membrane for this instrument.

Doesn't hurt to ask.

 

 

Regards,

 

 

Lawrence

[Don Solaris]

Scenic: How many beers did you have before

Looks like something else (than beer).... :lol:

[ElectricPuppy]

Thanks very much, Lawrence, I'll look into that.

[ElectricPuppy]

Update the Second:

 

Nobody I've contacted so far has new panels, so replacing them would mean finding someone who's had replications made, or have it done myself.

 

HOWEVER, I may have a fix for this with the existing panels after all. In a moment of desperation, I tried soldering very small gauge wire directly to the conductive ink on the membranes. I experimented with a broken piece of ribbon and found that it's actually possible to do this provided that the iron is kept below 400F! The solder joint actually seems very good. I'm shocked as hell that this even works, I expected the plastic to just melt away, but it didn't. Raising the iron temperature above this, though, causes the conductive ink to melt and ball up, but the plastic still remains intact.

 

Yes, I know, I should probably have given up by now.

 

New plan: Solder 30 gauge (wire-wrap wire) to the ribbons, remount the membrane panels, solder the wire-wrap tails to the landing boards I've already made and voila! (I hope!) I'll try to tackle it in earnest tonight.

[flattop]

Update the Second: Nobody I've contacted so far has new panels, so replacing them would mean finding someone who's had replications made, or have it done myself. HOWEVER, I may have a fix for this with the existing panels after all. In a moment of desperation, I tried soldering very small gauge wire directly to the conductive ink on the membranes. I experimented with a broken piece of ribbon and found that it's actually possible to do this provided that the iron is kept below 400F! The solder joint actually seems very good. I'm shocked as hell that this even works, I expected the plastic to just melt away, but it didn't. Raising the iron temperature above this, though, causes the conductive ink to melt and ball up, but the plastic still remains intact. Yes, I know, I should probably have given up by now. New plan: Solder 30 gauge (wire-wrap wire) to the ribbons, remount the membrane panels, solder the wire-wrap tails to the landing boards I've already made and voila! (I hope!) I'll try to tackle it in earnest tonight.

 

I would be inclined to suggest stranded wire considering the bends that they will most likely need to make. This might help with the stress on the existing plastic.

[ElectricPuppy]

Thanks, Wes. Actually, the wire-wrap wire seems to be plenty gentle tension-wise.

 

Also: SUCCESS!:D:D

 

The Polaris lives! All buttons work again, and with a few final touches, I'll be pressing it into service once again as my one and only pure-analog kit. (I don't count the Juno or Korg with their DCOs )

 

All in all, I think this is the best solution, but I would do things differently if I had to do it again. As it is, I don't think the buttons themselves have long to live anyway, because I think the plastic is failing there, too. The only reason they haven't failed already, I think, is due to how they're sealed inside the membrane sandwich. Eventually, though, I think they'll die. Who knows when.

 

I have a ton of work in progress pics which I'll post if there's enough interest.

 

 

Wheeeeee! it works!

[ElectricPuppy]

Since I have time to spare it seems, I'll go ahead and eat all your bandwidth with these FASCINATING REPAIR PHOTOS!! Huzzah!

 

BEHOLD the membrane panels, removed from the cover for your enjoyment. Actually, at this point, I had gotten desperate and was willing to try anything, so fully expecting to destroy them in the process, I pulled them off. Amazingly, they came off reasonably willingly. Note how short the ribbon tails are now.

 

The obverse:

 

Close-up of the worst-case ribbon, note the new crack rabout 1/2 inch from the end. These poor ribbons just WILL NOT tolerate any more bending, or else they get pissed and punish you by falling apart.

(Sorry about the blurry, I really need more lighting, or a damned tripod)

 

At this point, I'm stuck for ideas, and my wife says, "why don't just you solder to the traces?" Yeah, right. I could just see the plastic curling up and melting. But, after a while I though, oh what the hell, I'll try it on one of the broken pieces.... and voila! it works!

 

Key Points:

- You MUST have a temperature-controlled iron. I have a nice Weller that let's me dial in what I want, which in this case appears to be NO MORE than 400 F. A low-wattage iron is not necessarily a low-temperature iron, so if you want to do this yourself, beg, borrow or steal a temperature-controlled iron to do this.

- Use lacquer thinner to remove the green insulating coating, but only enough to expose, say, 1/4 of trace, don't need more than that.

- Apply a gentle liquid flux to the trace.

- Load up the tip of the iron with solder. This is not usually how you solder, but we need to be fast here.

- Lay the new wire lead over the trace, and touch the solder-laden iron tip to it for just a couple of seconds. If everything's clean, the solder will flow right to the trace. If the wire's not already tinned, tin it first!

 

I used 30-gauge wire-wrap wire here, which is plenty than enough to carry the logic-level current that flows through them and doesn't exert too much pressure on the connection. We want to baby these ribbons, no serious tension or torsion allowed!

 

Notes about above photo: I was experimenting with heat range. Note themissing middle trace... too hot, the conductive ink trace balled up and dissapeared. The extreme left was an experiment with conductive silver ink, which just plain didn't hold anything. Thinking on this now, solder paste might have made life a bit easier, but I don't have any, and might need more heat then we want to use here anyway.

 

Now, the obverse of the practice piece, letting light shine through to see how viable the traces still are:

 

The damaged trace was done with the iron set at 450. Even the plastic started to deform at that temp. Also notice that some of the traces now have ittle pinholes, like the one above the burned-out trace. Spent too long on the trace with the iron. BE QUICK! If you aren't totally confident in your soldering abilities, find someone who is.

 

The entire membrane panel had a whole layer of adhesive, a sticky, gunky, stretchy adhesive that, now pulled apart, has no chance of keeping the panels stuck to the cover when I put it back together. So, it has to go. Here I've started from the upper right and am working towards the left.

 

Unfortunately, some Goof-Off saturated bits of adhesive found their way under the panel while I was working on it, and now the graphi overlay has some specked spots. No help for this now, unfortunately... grrr.

http://www.polkadotdictator.net/kss/repair2%20016.JPG>

 

OK, here we go wit the Real Deal. Remove a portion of the insulation thusly:

 

Hold back the backing layer with a 3rd-hand (out of frame) and solder them leads! I cut the leads to be longish, no reason to be chintzy with wire.

 

One side done, now the other side:

 

 

To be continued...

[ElectricPuppy]

[continued]

 

Voila!

 

I should note that the backing that I've got held up here eventually failed at the bend and broke off, another reminder that the plastic MUST NOT BE BENT anymore.

 

Further testament to my geekdom: At one point I held the panel up to the light and noticed that it's generally transparent except for the traces and the black portion of the graphic overlay. I briefly thought about ways to backlight the panel. Maybe someday.

 

 

 

On panel done!

 

 

 

Fun shot: The cover sans panels. If the panels finally fail for good someday, I'll just drill this panel and mount discrete switches and find someone who can silkscreen new graphics directly on it.

 

 

 

Threading the leads through the ribbon slot in the cover. The shiny plastic on the edge is several layers of plain ol' packing tape to keep the bare traces insulated from the cover.

 

 

 

Panel temporarily attached with tape, just to keep it in position while I work on the back. Unfortunately, I don't have an appropriate adhesive to stick this down with yet, but I want something that I can undo later if necessary. I'm leaning towards common kids rubber cement.

 

 

 

Appearance from the back:

 

 

 

Threading the second panel:

 

 

 

To be continued...

[ElectricPuppy]

[continued]

 

Now the nitty gritty: Here's the left panel's leads tack soldered to the terminating board I made. Note the now-useless, original ribon connectors I had mounted thinking I could just plug what ribbon I had left into it. The bad news here is that I had hot-glued the board down to the cover and it won't come off without breaking. Since I don't have another PCB to cut up, and my patience was running out anyway, I just tack-soldered the wires to the exposed legs on the backs of the ribbon sockets. Not the best solution, but what the heck. Yes, I left a lot of length on the leads, on purpose. I want whatever bending forces that lead from the board to the ribbon to be taken up entirely by the wire if possible, I DON'T want to stress the ribbons!

 

 

 

Here's I've remounted both PCBs and plugged in the custome cables that lead from the termnating board. You'd never know it looked like crap underneath.

 

 

 

The other pair of connections on the right panel. Here I hadn't yet glued down the board so i was able to solder the wires properly to the copper pads underneath. HOWEVER: I wouldn't do it this way again. Instead, I would mount wire-wrap posts to the board and use the wire-wrap leads as intended, wrapping them to the posts. Trying to solder these damned thin wires to the PCB pads was a PITA.

 

 

 

And that's it! All ready to go:

 

 

 

Blurry proof!

 

 

 

Things I would do different:

- I'd use wire-wrap pins to terminate the leads from the ribbons.

- I'd probably shorten the leads a little more, they were too long, but i was impatient and didn't feel like cutting/stripping them again.

- Be more careful about where I place the boards. The one for the right is banging into the board that's mounted on the back of the case, darn it. I may actually have to move it after all at some point.

 

Otherwise, that went about as well as I could have hoped. Hurray for reviving dead gear!

 

The End.

[carbon111]

Congrats! Some hairy work there, my friend.

 

Pints all around!!!

 

[Allerian]

Holy cow. I hadn't seen this thread - you done good.

[ElectricPuppy]

Thanks, gents! It's still sitting on the bench even now, but I plan to button it up and squeeze a demo clip out of it this weekend, muse willing.

[grimaila]

ElectricPuppy,

You rock!

It just goes to show how persistence and patience can pay.

MikeG

[Allerian]

Honestly, I'm not sure how you resisted redoing the panel graphics. I can however see where you were probably just relieved enough to get it all together and working again to deal with a whole 'nother subproject.

[Teknobeam]

I learned about this method of repairng the polaris from one of the members on the Yahoo Polaris forum.

 

http://launch.groups.yahoo.com/group/chromapolaris/

 

I have repaired two of these machines. On the first one, the ribbons were too short to work with so I had to drill holes and install momentary switches. (huge job). On the second machine the ribbons were broken but there was a lot of material to work with. I cut them, then I used nail polish remover and a Q tip and carefully brushed the green insulating coating until it exposed the contact legs. As soon as you get to the legs stop with the nail polish remover and wipe off any excess with a paper tissue. Then de solder the edge connectors from the PC board. Attach some jumpers to the edge connector legs and solder the other ends of the wires into the old holes that the edge connectors used to occupy. then carfully seat the edge connector into the shortened and exposed ribbon. A new machine.

 

Teknobeam

[Teknobeam]

This was the first polaris that I resurrected. I bought it on Ebay and the guy told me that I could easily repair it with some "liquid solder" which he generously included. The left side ribbons were broken almost at the point of entry into the metal lid so it was really a hopeless situation. the right hand ribbons were also broken but could have benefitted from solution #2 had i known about it

 

After about a week on and off in my spare time trying to attach the liquid solder to the broken ribbons, I gave up and wondered if it would be possible to install all new switches. I removed the top layer of the existing membrane panels to expose the membrane switch circuits. This kind of destroyed the graphics overlay finish but revealed the circuit diagram. then I removed the rest of the material from the control panel and laid out the holes that the switches would fit into (not much room for switches, very tight). After reverse engineering the circuit diagrams from the old membrane panels, I installed the switches and soldered them all together. I took the damaged control graphics over to my inket printer and photocopied them onto photo grade paper with adhesive on one side until I got the colour and the size exactly identical to the originals (required some touching up in photo paint where the tears and cracks were on the originals). Then I adhered the new graphics panels to the contol panel lid and used some waterproof transparent, matte finish mylar (sticky on one side) to protect the new graphics. All that was left to do was cut out all of the slotes and holes in the new graphics panels to allow for the switches, LED's, and sliders to pass through. This was a lot of work but I had fun doing it. Of course I recommend repair solution #2 if you have enough ribbon left to work with, it's so much easier lol.

 

teknobeam

[geobrick]

ElectricPuppy,

This was a great service to all Fender Chroma Polaris owners. Thanks for posting it.

 

I bought 2 of these new (in the mid 80s?)

 

I recently discovered that I couldn't get the lower function switch to work on one of them. After some web research, I discovered there were problems with the ribbon cables. I took it apart to start the repair.

 

You can't over state how brittle the ribbons are. After breaking away the brittle part, I still had enough slack to repair it and reach the connecter on the board. The only thing I couldn't figure out was how to get the green backing off. Your thread explained it perfectly (lacquer thinner). By the way, before I noticed that the green backing needed to be removed, I reassembled the now shorter ribbon and most things worked fine (but some things were a bit flakey). I took it apart again and noticed the green backing.

 

So far, I only had this problem with the three conductor ribbon between the 2 boards. The rest of them seem fine for now.

 

One thing you wondered about much earlier in the thread was whether the MIDI implementation on these is comprehensive enough to use it as a sound module. It definitely is! You can execute any button push and slider move via MIDI system exclusive messages. So if it ever gets to the point where you can't repair it or don't feel like fixing it. It will make a great sound module. I mostly use mine in that way. Don't throw them away!

[ElectricPuppy]

Awesome, I'm glad my little experiment was helpful! Thanks!

[Waveterm]

Thanks Puppy for all the hard work you put into this. It will help me repair a PPG EVU with the same type of problem.

 

WT

[ijbandman]

Just bought a polaris and found the midi does'nt work. At least I don't think. I have reset and it still doesnt play sounds on the Nova. I know it gives functions about midi e.g LF,10 = MIDI reset Pretty lights come on but it still doesn't play MIDI apps. And the guy I bought it from doesn't have the orginal sonds installed. So if it doesn't MIDI (shoots MIDIox) and I don't have a cassette interface. What can I Do....HELP!!!!!!!!!!

[ijbandman]

With my trusty Tascam US-144mkII audio interface, and Midi Ox, I downloaded all factory sounds. It only took 6 hrs to figure out and a barrage of Slim Jims:thu: