Roland Cr5000 Compurhythm (1980) 

Analog drum machine, preset version of the more famous CR8000  (minus the clap). It's the machine missing link between the Cr78 and the cult Tr808.
You can read it HERE more information  about the Cr5000 

O Cr5k, Cr5k, wherefore art thou Roland?

Well, I used to have a cr8000 some time ago: sold it for desperation of a bad repair on the famous not working buttons. A technician did this job for me at the time and, sadly, the buttons were all misaligned and the CR8000 looked quite ugly like a rake. I was not really happy with that. 

Years later,  reverb-quotation made the price of 8k rocket up and quite impossibile to find one at a reasonable price. Looking for a cheap replacement,  I found a Cr5000 in Verona Quizano in the evergreen craigslist - ok not the same, but the sound at least is there. The guy won't ship, but I managed to ask I friend who's living in the nearby Colognola ai Colli to grab it for me, as the cosmetic condition were excellent.

 It was also specified the Cr5000 was perfectly working. Was it true? ok guess it. 

What's wrong with it?

Ok as expected 80% of buttons simply don't work. Some you need to jump on them with a fat elephant to activate something.
Time to get my revenge on the repair since I managed to get more skills on those years. First I read a lot of DIY solution on the net, since there are no actual replacement  (the boss stompbox are quite similar but with different pins and height, and, if available, are pretty damn expensive). No one have really a solution to repair those buttons. Anyone to produce new buttons?

UPPER The drum machine is easy to open: 7 screws on the bottom and 3 on the rear.
The button panel is then fixed with 6 plastic pin (you just have to pry them ). No need to remove any flats nor special cables but some nuts on the  volume, and data shafts.
Of course for your safety remove any plug power, and stay away from capacitors, but you don't have to deal with them on this section, so just leave them alone.

UPPER  - ok everyone who ever opened a cr5k/8k still wondering why Roland did place 3 metal brace-frames to hold the buttons. Ok, I know the answer: for alignment. The frame will not help desoldering and removing the buttons out of it! The soldering is on both layer, thus I highly suggest to use a desoldering station at 300-350 Celsius; the welding pads are pretty solid and won't lift so easily, that's the only good news.
Once you desoldered properly  all 4 pins free ( just  make them wiggling) you have to use two screwdrivers to bend 2 plastic tabs toward the shaft and push up the button at the same time. You should hear a click sound meaning you're on the good way. Hint: try first  the Intro/Fill and Start/Stop buttons because they aren’t held in place by a metal brace like the others.

UPPER Once you have removed the first button (1 out of 22, more if you have Cr8000) carefully  open the button using something sharp on the opposite side of the frame-brace tabs. These a are T-shaped old plastic -  go really easy as those will break-
The CR button is composed by 5 parts: contact, rubber plunger, spring, plastic shaft and upper enclosure.  How lucky am I:  the internal is all greasy, someone sprayed a lot of stuff on it hoping that will repair thing. Sweet I have to clean up all that mess before.

At microscope

The critical parts are the contact and the rubber grafite. The contact buttons are 2 little pins that are often oxidized , carefully I cleaned with alcohol and removed all black residue with qtips, A LOT of tips. Once more: don't not use too much force on the tiny pins! 

Once contacts cleaned, it's time to check the graphite on the rubber plunger.

UPPER: Closing the contact on the button, I had a 10kOhm resistence wich is really not good. The problem is that cleaning grafite can worsten the situation. I read a lot of difference DIY solution around: spray grafite (I tried, bad, poor conductivity), gluing copper to the contact plunger (I do hate repair with glue, so no) or silver conductive paint, the best solution for me. Anyway, try what your prefer, and once you reached the 100-150 Ohm you should be ok with contact with modest pressure. Yes, it's a loooong and boring job.

Reassembling and testing

Just put back the buttons on the tedious holder frame, yes, now it's all working!  very nice punchy sound!

If you need 

English user manual


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