Ive had 4 of these pc 88s now. I remove the entire hammerweight assemblies and glue the shit out of both flat sides of the weight, applying enough glue to fill the holes that go down to the metal. I take a popsicle stick and smooth the glue out and into the holes. Its easy to do quickly by holding the assemblies vertical and staggering the weights every other weight, so its easy to do about 10 weights at a pass. When Im done with one side, I let it dry, then flip it over and do all of the weights on the other side. Then after thats dry, I apply some glue to the tabs that break off. I use DAP Rapdfuse glue. You have to do it in a ventilated area because the fumes burn the eyes and give you a sore throat. I do it in the bathroom with the fan on, then leave the assemblies to dry in there for a while..... Also....when you have to change out a broken HAMMER WEIGHT, sometimes the red felt does not want to cooperate when restringing the hammers. It snags on the metal rod. You have to hold a smallish flathead screwdriver and put presure on the red felt, while running the rod through the hole. If the red felt snags and you dont do this, the hammer weight will not move freely, and you will have to fix it!
Preventative gluing - thin application on to the sides and bottom of the key weight is a success. It's been seven months so far, with brief but almost daily play.
doing a key weight repair now. I've tried Duco Cement(for phenolic plastic and others, but not polystyrene) and Duco Model Cement (for polystyrene). And cyanoacrylate liquid. Cleaning grease off the weights first with isopropyl. I was told you can select the two Duco products, find a test spot on the unknown plastic, remember them (!), and see which one has a slight ability to liquify the plastic. On dark colored plastic this works very well. On white plastic, at least these key weights, this isn't so helpful. The good new is that all three appear to be adhering very well. I will update this with results.
I was not able to identify which kind of plastic it is by the above test. Could be neither. But I have fixed my broken keys and, more importantly, I have put a preventive layer of glue on all the key weights. If you do a key weight repair, look at the other key weights and you'll see the cracks in the plastic. Top, bottom, and sides. In an effort to use the right glue, I used several! Like this - I was able to keep the key weights on the rod. I smeared a thin coat of Duco cement on the tops of the weights, and let it dry. The other Duco model cement on the bottoms - let it dry. Then you can pivot the weight upwards and smear the sides. For this I used cyanoacrylate. It was not difficult to avoid gluing the keys together, but do be careful. My advice is to NOT remove the key weights from the rod! Sticking the rod back thru all the weights will easily dislocate the red felt. This took a very long time. This video does skip some disassembly steps, but just take photos and write notes as you disassemble the keyboard. My keyboard has been fixed and played on for one month now as of 9/5/17. If any key weight breaks ever, I will reply to this post in the Kurzweil PC88 Repairs Part 2 - Glue Experiment you tube video. So if you send a link to this vid it should be up to date. Parts are not available, but this repair can be done. Having done one, I think doing this again would take me at least 4-5 hours, spread over a week for glue drying. I would consider cyanoacrylate to reduce drying time - it seemed to hold well, but I did not feel like experimenting with this. If I was still in the repair business it would be worth experimenting to see if cyanoacrylate holds up over time. Watch the drips.
Very useful videos. Thanks. I would suggest you get the camera closer and focus on the small parts (even if you're out of the frame, sorry :-) ). They're the most important and we can't wee them clearly.
Help please, when I press down sustain pedal it will not sustain but it does change the reading in the window so I know it’s getting some kind of contact. The window reads "zone:1 SwitchPd1, SwType: momentary. . Can anyone tell me what this means.
i have my pc88mx apart to repair some weights. But I can figure out how to get the weights off the axle bar. The axle doesn't move and there's not much to grab onto to try and move it.
The rod assembly can be braced against a support with a hole in it and then the axles can be pushed out. If necessary lubricate with Protek spray lube.
Hello there friend. I am a Solidworks CAD engineer. I could design a plastics mold and or improved design of the key weights. Im am a Kurzweil fan and Would willing to help keep these great keyboards alive. Reach out and mail me a spare or broken part, so I can reverse engineer a a part file to be 3d printed or injection molded.
Ive had 4 of these pc 88s now. I remove the entire hammerweight assemblies and glue the shit out of both flat sides of the weight, applying enough glue to fill the holes that go down to the metal. I take a popsicle stick and smooth the glue out and into the holes. Its easy to do quickly by holding the assemblies vertical and staggering the weights every other weight, so its easy to do about 10 weights at a pass. When Im done with one side, I let it dry, then flip it over and do all of the weights on the other side. Then after thats dry, I apply some glue to the tabs that break off. I use DAP Rapdfuse glue. You have to do it in a ventilated area because the fumes burn the eyes and give you a sore throat. I do it in the bathroom with the fan on, then leave the assemblies to dry in there for a while.....
Also....when you have to change out a broken HAMMER WEIGHT, sometimes the red felt does not want to cooperate when restringing the hammers. It snags on the metal rod. You have to hold a smallish flathead screwdriver and put presure on the red felt, while running the rod through the hole. If the red felt snags and you dont do this, the hammer weight will not move freely, and you will have to fix it!
Thanks for this video, it help me a lot! Would you tell me the exactly description of that “Epoxic” that works?
Preventative gluing - thin application on to the sides and bottom of the key weight is a success. It's been seven months so far, with brief but almost daily play.
doing a key weight repair now. I've tried Duco Cement(for phenolic plastic and others, but not polystyrene) and Duco Model Cement (for polystyrene). And cyanoacrylate liquid. Cleaning grease off the weights first with isopropyl. I was told you can select the two Duco products, find a test spot on the unknown plastic, remember them (!), and see which one has a slight ability to liquify the plastic. On dark colored plastic this works very well. On white plastic, at least these key weights, this isn't so helpful. The good new is that all three appear to be adhering very well. I will update this with results.
I was not able to identify which kind of plastic it is by the above test. Could be neither. But I have fixed my broken keys and, more importantly, I have put a preventive layer of glue on all the key weights. If you do a key weight repair, look at the other key weights and you'll see the cracks in the plastic. Top, bottom, and sides. In an effort to use the right glue, I used several! Like this - I was able to keep the key weights on the rod. I smeared a thin coat of Duco cement on the tops of the weights, and let it dry. The other Duco model cement on the bottoms - let it dry. Then you can pivot the weight upwards and smear the sides. For this I used cyanoacrylate. It was not difficult to avoid gluing the keys together, but do be careful. My advice is to NOT remove the key weights from the rod! Sticking the rod back thru all the weights will easily dislocate the red felt. This took a very long time. This video does skip some disassembly steps, but just take photos and write notes as you disassemble the keyboard. My keyboard has been fixed and played on for one month now as of 9/5/17. If any key weight breaks ever, I will reply to this post in the Kurzweil PC88 Repairs Part 2 - Glue Experiment you tube video. So if you send a link to this vid it should be up to date. Parts are not available, but this repair can be done. Having done one, I think doing this again would take me at least 4-5 hours, spread over a week for glue drying. I would consider cyanoacrylate to reduce drying time - it seemed to hold well, but I did not feel like experimenting with this. If I was still in the repair business it would be worth experimenting to see if cyanoacrylate holds up over time. Watch the drips.
my question is!
why do most of the keys on my krzw.pc 88 bang? thanks in advance
Very useful videos. Thanks. I would suggest you get the camera closer and focus on the small parts (even if you're out of the frame, sorry :-) ). They're the most important and we can't wee them clearly.
thanks you...... question that I have is I can remember when I took the pitch control which plug it goes to.....can you help me????thanks
I noticed on my PC88 that 2 keys are louder. Can you tell me what the problem is? I would be very happy for an answer. Bye drflodo
They don't make replacment hammers for these anymore? i have a problem with my k2600 one of the hammers is broken.
Help please, when I press down sustain pedal it will not sustain but it does change the reading in the window so I know it’s getting some kind of contact. The window reads "zone:1 SwitchPd1, SwType: momentary. . Can anyone tell me what this means.
i have my pc88mx apart to repair some weights. But I can figure out how to get the weights off the axle bar. The axle doesn't move and there's not much to grab onto to try and move it.
The rod assembly can be braced against a support with a hole in it and then the axles can be pushed out. If necessary lubricate with Protek spray lube.
Hello there friend. I am a Solidworks CAD engineer. I could design a plastics mold and or improved design of the key weights. Im am a Kurzweil fan and Would willing to help keep these great keyboards alive. Reach out and mail me a spare or broken part, so I can reverse engineer a a part file to be 3d printed or injection molded.