Random clicking and buzzing.

Disassembly the unit.
Your question is less detailed. If the keys is broken,replace with new.
If you mean "How to",then you need the service manual.
Outputs problem,usually causes by output IC (or input IC) is defects.
It also can cause by AD/DA IC is error.

buy some strips of velcro with the tape on one side..cut out your pieces and mount them to the hammer..

The Roland RD-600 is a digital piano, and its hammer action mechanism is designed to simulate the feel of an acoustic piano. The hammers in digital pianos like the RD-600 are typically made of materials like plastic or a combination of materials to replicate the weighted feel of acoustic piano keys.
The breaking of hammers in a digital piano is not a common issue, and it's not typically related to the age of the instrument alone. Several factors could contribute to the breakage of hammers, and it's essential to consider the following possibilities:

1. Excessive Force: If the keys are played with excessive force or if there's any physical damage to the instrument, it could lead to the breakage of hammers.
2. Material Quality: The quality of materials used in the construction of the hammers can impact their durability. If the hammers are made from subpar materials, they may be more prone to breaking.
3. Manufacturing Defects: In some cases, there could be manufacturing defects that make the hammers more susceptible to breakage.
4. Maintenance: Lack of proper maintenance, such as cleaning and regular inspection, may contribute to the wear and tear of components, including hammers.

If you've observed a pattern of hammers breaking with regularity, it might be worth investigating the specific cause. If it's due to excessive force or physical damage, adjusting playing habits and taking care during transport can help mitigate the issue.
As for whether it's worth purchasing new hammers from Roland, it depends on the extent of the damage and the overall condition of the instrument. If the RD-600 is in good condition otherwise and you enjoy playing it, replacing the hammers could be a reasonable option. However, you may want to assess the cost of replacement hammers compared to the overall value of the instrument, factoring in the cost of a used RD-600 and any potential future maintenance needs.

One of the lines in the keyboard scanner has opened up. I have an idea what it might be and it is a nasty problem involving circuit traces that are silver conductive paint on a plastic insulating base that separate from a jumper at each end of the strip that the key contacts are made by conductive rubber pills pressed down by the keys. The contact of the flexible circuit under the keys to the jumper cable can be broken by vibration. I have an EPS7 with the problem and other than replacing the whole contact strip under the keys it really has no easy solution.You should probably have a Roland shop look at this problem. If your unit has this same arrangement it is repairable only by replacing the whole key contact strip.

This depends on "how" they are "broken".

Many of the keyboards with semi-weighted keys get the keys knocked out of the pivot points and one has to open the unit and reseat the key and/or the key spring retainer.

If the keys have broken parts, replacement is the only option.

You either did not get the ribbon cable seated OR got it upside down.

If this cable is the flat ribbon with exposed solder plated points of contact, OFTEN those connectors have a latch to release by GENTLY moving tabs on eaither side in the direction of pulling the cable out. This lock MUST be moved out slightly to allow the cable to seat properly. The solder plated contacts will be FULLY into the connector when seated properly.

These cables ALSO can be inserted backwards and NO connection will be made.

Call Roland to get replacement parts. Go to the Roland website and go to Support/parts.

Did you ever get hold of an FP-8 service manual? The weight replacement is relatively simple: The case opens by removal of eight screws, four at each end on the underside. The top then hinges up. Keyboard assembly is removed by first unplugging the two white ribbon connectors at the center, then removing the screws at the front edge (underneath) and the screws (gold) at the back of the assembly (accessible from the top). Keys pop out by spreading the two "wings" at the pivot point, and then the weights (Roland calls them "hammers") lift out. Roland will sell you new ones, but I have no idea whether the replacements are any better than the originals. I've done two of these pianos so far, and have a third waiting to be worked on. I do have a service manual, but I think I downloaded it freebee somewhere.
The other failure mode on this piano is the electolytic coupling caps on the output board - I've replaced all of them on both pianos - don't remember the value offhand.
Paul Prestopino [email protected]

Try Roland.com on the internet. It's a pretty good website and should show you dealers in your area.