Working on the keyboard today, not a computer one but a midi one a Roland EP.7 II.
Roland used a red epoxy that gets soft and gooey over time. Add in the Texas heat and you have dripping red sticky goo and weighted keys that the weights fall out of. This leads to keys sticking together and keys being jammed by fallen weights.
I should be doing this up in vector as it is hotter than all outside today. To clean it you need lye and water and a lot of elbow grease. Once it’s cleaned up I’ll need some two part epoxy to put the weights back in the bottoms of the keys.
Here’s the first clue something is wrong… dripping epoxy and falling weights in the bottom case.
Keys have been cleaned, rinsed, washed, and dried. All but three missing weights are cleaned and now dry… I just wished I dried them rather than letting them dry to avoid the rust.
The key bed frame and the last three key weights are now soaking in the lye and water mix to clean the epoxy off it. Those last key weights were hiding in the top cover.
Next up, installing the key weights followed by reassembly of the key bed. I still need to clean up the case bottom, PCBs for the keys, and the case top.
The flat rectangular weights go in the white keys while the Tetris shaped keys go in the black keys. I bought some 2 part epoxy to mix up and set the weights tomorrow.
@brenly - I do have a YT channel, but don’t have a lot of content out there. I will be recording the upcoming online monitor repair class and posting it to there. I’ll be doing it for our local retro computing FB group, but I think @mrcity will put up an invite on the DMS calendar under VECTOR for folks here who want to watch it.
“…All but three missing weights are cleaned and now dry… I just wished I dried them rather than letting them dry to avoid the rust…”
If the rust on the weights is difficult to clean, maybe electrolysis is an easy solution. Possibly set the weights on some heavy screen material to avoid having to attach to each weight.
I tried this for the first time several weeks ago. Didn’t have the recommended Arm & Hammer Washing Soda, but baking soda worked for me. I was pleasantly surprised at how well the rusted item cleaned up.
I have a tumbler somewhere in the garage and that idea crossed my mind as I didn’t know if using a rust removing solution like Evaporust would cause the epoxy to not stick.
Xylene and Toluene – Aggressive solvents for cleaning; may damage plastics or paints. MEK – Very aggressive solvent for cleaning; may damage plastics or paints
And I don’t want to risk the plastic keys getting damaged.
oh i would absolutely love to watch a monitor repair class on YT. if you dont already know, thats actually how to get a very affordable gaming monitor since they do a wide range of good resolutions and refresh at 100hz which is way better than the standard 60hz.
I believe the retro computing group meets on days that dont work with my work schedule, so i’d love to see a recap later.
When reassembling, go by shape, not by key # as those numbers are just mold markings and not significant to position. On this Roland all the springs for the keys are identical.
Beware of the slight differences in middle keys. The shaft for the keys in the middle of the section with 2 black keys is thicker than the ones in the group of 3.
The keybed was pretty gross. I picked up a 70 quart under bed storage tray with lid from Lowe’s and filled it with water and lye. I stripped the felt off and the key guides and put the guides and the metal keybed into the solution. It fit diagonally on edge in the bin just fine, but an 88 key definitely won’t.
I left it overnight then scrubbed it down outside with the hose, scrub brush, and soapy water before thoroughly drying. I picked the 76 key guides out of the bin and put them in the dish of soapy water and took them inside to finish cleaning them. The solution took care of all the epoxy, but I had to put on new felt as the old was contaminated with epoxy drips soaked into it.
Rubber gloves are needed. I splashed some on the back of my hand and it immediately started burning my skin. A quick splash of water took care of it and no marks on my hand were seen afterwards. That solution is really nasty.
It took 2 tubes of the JB Weld 5 minute plastic epoxy to do all the weights. Keep some Q-Tips around to wipe up excess epoxy from inside the black keys or they will drag on the key guides. If that happens, you can trim out the excess carefully with a sharp hobby knife (Xacto, or similar.) Put a blob of the epoxy on the bottom of the weights, insert them into the key, then press down on them to seat them and spread out the epoxy.
You can buy the exact felt online, but I was in a bit of a hurry. Lowe’s carries 3M adhesive backed felt in a spool that is 1/2" wide by 60" long. Cut it down the center with a sharp pair of scissor and it’s perfect for under the key guides. They also have 4x1" strips that are brown and the same thickness and stiffness as the green felt. You just have to use a ruler and a sharp hobby knife to carefully cut them into 4 equal width 4" long strips. Line them up end to end and they work very well.
Keybed installed. This took a couple of tries to get right. I had to remove and reinstall the pcbs a few times to get all the contacts cleaned and working properly.
restore!
