How do I fix a Roland Digital Piano FP-8 that has refused to play sounds despite the fact that it displays lights?

Read this please

https://www.justanswer.com/electronics/9xlyw-roland-digital-piano-kr-4500-piano-turns.html

and these

https://www.google.com/search?q=Roland+kr+4500+no+sound

But you will probably need a service centre for replacing components.

Ch?o b?n, v?n ?? n?y c? kh? ??n gi?n, ??c bi?t ? Piano ?i?n hay c? tr?ng th?i n?y, b?n c? th? ghi l?i c?c ph?m b? m?t ?m thanh, sau ?? m? ?ai ?c ra, b?n d??i ??n c? n?t cao su b?n ch? c?n b?o v? c?i n?t ?? l? ???c.

https://guitardongtam.com/

MIDI cable and MIDI ports

go to the utility settings, accompaniment settings..turn off.

Replacing the electrolytic capacitors in this keyboard would require you to be somewhat experienced in electronic soldering, especially the surface mount electrolytics. You should be able to find how-to videos on YouTube if you are curious. You also probably do not need a service manual. The values of the capacitors should be printed directly on them. Replace them all. Replacements can be ordered from Mouser. BUT, I suggest at least bringing in a friend that has experience with these types of repairs. These circuit boards are not designed for inexperienced soldering!

Here's a link to the Owner's Manual
for a service manual, you're probably going to have to contact Roland directly, since they don't even list the fp-8 on their website. Service manuals for their other products only run about five bucks for a hard copy, i believe. I'm sure you can get to the right place through here: http://www.rolandus.com/corporate/contact_us/

I first would suspect the switches on the eadphone jack. Normally these cut off the speakers when headphones are plugged in. These jacks and the switches are really weak, poorly made, and easily broken, especially if headphone cord gets yanked.

your sound process digitaliser has burned out the crackling should have warned you as to the fault and had it replaced (fixed) right away this is a simple repair but does need to be done by an electronics tech

White spirit is NOT what you should use. Mineral spirit leaves a residue film.

Use 99% isoprophyl alcohol.

ALSO inspect the contactboard for cracks by candeling with bright light behind it.

Roland FP is a nice keyboard but has a known problem on cracking key weights. There is a counter weight under each key to push the key upward. There are two sizes of weight beams, longer one for white keys and shorter one for black keys. Roland did not make the original weight beams strong enough to last. They will crack and eventually break. When it happens, the key will stay down. Fortunately, they can be easily replaced.

Roland FP-8 has 4 black screws at the bottom on each side end. Remove the screws, flip the ends up and expose the interior. Near the hinge of the problematic key, carefully ply open the hinge tabs and remove the key from the hinge. You will find a weight beam under the key. Remove and inspect the weight. There should be a metal wrapped in a plastic beam. If the metal part is missing, find the missing part and replace with a new beam. You can order weight beams from Roland. It costs about $10 each plus shipping. Put everything back in the reversed order.