Help me clean the mess.

Here's an article for you.

https://www.digitalpianoplanet.com/how-...tal-piano/

I suggest you use this:
https://www.worldofchemicals.com/542/ch...onics.html

I managed to gentle remove the tape cable, and remove screws. This is the situation:

Dirty all over some areas.
I will buy a special spray used by profetionals to clean circuit boards.

How do I know if it's time to buy a new set of rubber contacts strip?
Maybe I should buy while they still manufacture sets that fit in my DP model, don't you think?

I confess I'm afraid of remove the rubber strip to clean the contact. It' feels so smooth, so fragile

Thanks for the tips.

I think in buy a new set of rubber strip before they stop manufacture the series that fit for this and other old models. WHat if my strip works for 1 year, and when fail I discover there is no longer for sale?

The rubber heels I saw a tip in other video, where someone used a tiny plastic of a tiny cable, thin as a pin head.

What scares me now is tyhe key removal, needed to be repeated 88 times.

These videoas shows key's removal similar to the keys of my model :

https://www.youtube.com/watch?v=JbPGkZNDeAQ    (see at 2:00)

https://www.youtube.com/watch?v=9iKyY5g77jY  (see at 6:40)

I'm really afraid to broke a key while removing or while placing back...
I tried with a lot of care but it's not easy as a it looks in the video.

Sounds like you're doing a really good job and that it's going well.  Good work!

I'd recommend that you can clean as much as you can with a vacuum, compressed air, a hand blower, or canned air, since that will get the majority of the dust cleared up and you can do that multiple times without disassembling much and there's little or no risk of hurting anything.  A second line of defense is a dry microfiber cloth.  To clean up what doesn't get taken care of by compressed air or a microfiber, you can use water, lightly soapy water (a simple soap with very few added chemicals), or a mild and diluted all-purpose cleaner (I usually use 303 but anything a detailer would use for all surfaces would be fine); however, only do that if you must and use as little as possible (don't spray the cleaner directly on and don't immerse anything).  I often use q-tips or small cotton swabs to gently apply and then remove any cleaner like that, and after a few minutes (or in arid climates like mine--a few seconds), there won't be any moisture or humidity from the cleaning and the part can be put back.  As long as any part is completely dried quickly after cleaning, you won't have harmed any of the electronics.  It can take a lot of time and requires diligence and patience, but since the goal is to make a $500-2000 keyboard last for a few more years, it's well worth it.

Isopropyl alcohol and a few other more aggressive chemicals can be an option in select cases--like cleaning the key contacts, but be careful of the surfaces you use it on because it can dry or denature many plastics, rubbers, or synthetic materials--again it's best to start with dry cleaning and only do really dirty areas with anything else.  When working with key contacts, there is a substance coating the contact that--when a key is pressed--forms a small circuit (which is true in MIDI keyboards, calculators, remotes, computer keyboards, etc.) and as the key is pressed over time, the substance breaks down into a powder which can be cleaned to allow more time before replacement, but it eventually totally rubs off (or becomes enough of a different shape that it stops working), which is when replacement is needed.  The other way that key contacts can fail is if the rubber frame dries out and cracks in such a way that the contact no longer returns to its original shape after a key is pressed--in that case, I don't know of any other option than replacement.

One ingredient in this circuit cleaner spray is isopropanol alcohol, and wikipedia says isopropanol it's the same thing as Isopropyl alcohol.The other ingredients in the spray is fluorinated solvents (evaporates 100% I think) and propelent gas (CO2 probably but I don't know).

I think it's logic presume all this ingredients evaporates with no residue.

Is it safe for the rubber strip contact?
I mean for the rubber itself and for the contacts inside the rubber and the small contacts in the circuit board area where the rubber strip fits.

In this video this brazilian used a similar spray to clea-up the contacts of the circuit board, but not at  the rubber strip and told to do not use in the rubber strip or the dark spots inside, but said to use a swab if needed to clean it:

https://www.youtube.com/watch?v=RiqTaitG4eo

Fast update... Still researching.

I found a incoherence between two different videos:

-In one a person said to use Contact Cleaner Spray only in the circuit board after remove the rubber strip, and he sprays in the board even in the board's contacts, and instruct to clean the rubber strip with a swab.

-In other video another person said to do not use Contact Cleaner Spray even for the circuit board's contacts. He told it could damage the contacts.

I'm confused now.. Can I use the Contact Cleaner Spray or not??? Or at least used after remove the rubber strip?
Can it remove some of the graphite from the contacts in the circuit board, and so create potential damage?

A good caution tip I found is to keep the eye in the rubber strip holes, since each rubber contact have two holes, one deep and one shalow, and if we reverse the orther (upside dow one strip piece by accident) it will not gonna work.
I will try to keep that on mind.

I agree with MrRoland.  Contact cleaner should always be safe on electrical contacts but not necessarily on other surfaces.  Also some contact cleaners contain lubricants that will remain after the isopropyl alcohol evaporates to "improve conductivity" or make it easier to unplug something later, so don't spray too much if you use it.  I usually use something like Deoxit for all purpose cleaning of circuit boards if compressed air isn't enough, and I only use contact cleaner for just the metal surface of electrical contacts--especially if I've had electricity loss or signal loss.

Graphite powder could help, but you could also use a remote repair solution like https://www.amazon.co.uk/REMOTE-RESTORE...B01M8LEOIV

I also use a rubber to clean delicate surfaces, but I never tried this on graphite or carbon contacts.

A pensil is conductive and this will increase the conductivity of the contacts, but it isn't very sticky so I imagine it won't last for a long time. Conductive ink might do a better job.

Graphite is made for drawing not contact strips.

I bought a rust remover, but not for the circuits or contacts, but for some of the metal structure of the frame who holds pices.

Today I got a plan B, if needed. I found 3 blocks from my home a small mobile technical assistance able to performe circuit repair on cell phones. There are very few on the city with such precision skills and tools for such small circuits. My Roland circuit lines it's surely not thinner than the ones from cell phones, so I think they could fix my circuit board if my cleaning do not come to solve the problems.

I my DP circuit need such precision repair, the technical from the musical organ&keyboard technical assistance, will have not such precision tool. There is only one in the city for digital instruments repair, but he probably can't repair very small circuits lines.
So, in case of need circuit board advanced repair, I still will need to reassemble everything to ge my DP in fine shape again, with all keys working well.

Thanks tmyoung.

The rust remover I bought it's not exactly what I thought, since it's in reality a rust converter, since it do not remove the rust but claims to convert it into a anticorrosion layer similar to a primer, and it looks dark after dry. When the seller told me I imagined it would remove the rust and bring back the metal color with a some protection against new corrosion. And the worst is that it only convert rust if it's a very thin rust layer and not in deeper rusted areas.

Wasted money? Whould I use it, since the metal frame is inside and not visible after assemble?
Anyway with rust converter or with rust remover, I will need to sandpaper many rusted spots that are not thin.

Thanks for the nice words.  :-)

I got concerned about the rubber strip (what is the formal name of it?). I removed just a small portion in the area the liquid spilled and the PCB was more damages. And to my surprise, the area underneath the rubber strip, the contacts and small cicruit area there, was clean and good looking as new. No deffect or dirty my eyes could spot.
That's because the rubber strip have a area in the sides (like a railroad) glued in the PCB. The portio of rubber I removed I managed to fit it again, but after fit the glue effect no longe it's there, and if I do a little tinny finger pressure there, I an see the edges of the rubber raise a bit.

So, unless I find the same glue to apply again, the rubber strips will be not as well protected as before. So thr question is:

"To clean or not to clean the ubber are contasts?"

Do it need to be clean, if even the area where the spill milk accident happened was super clean and new???
How coulde had gone inside the other areas I didn't checked, if the worst area of accident was looking perfect inside?

If I manage to remove the remaining rust, and the circuit board works for all piano keys, what product should I apply to avoid new future oxidation in thses specific areas? A acrylic varnish?

I'm puzzled how it oxidazied, if the PCB have a layer of plastic or varnish covering it. How water got there through the layer and reached the copper???

You've detailed it thoroughly.  Yes, there could be a few keys somewhere in the piano that have contact loss (most wear-and-tear of contacts will occur on the middle octaves of the instrument since they get played a lot more), but I doubt you'll get much of an improvement.  You're wise to focus on the circuit boards that have lost wiring.

I'd agree that you don't need to clean the contacts at this point.  Maybe down the road you'd need to clean or replace them, but if liquid made into the circuitry enough to corrode the copper and break connections on the boards, that's a hundred times more problematic than a couple of aging contact pads.  Your plan to do as little as possible until you're certain otherwise is very wise.

What the current draw, etc. usually varies from manufacturer to manufacturer and from model to model.  Your best bet to answer that question is to find a diagram like this one which gives a circuitry "map" in standard electrician-speak that will tell him exactly what each wire/thread/cable/connector is doing.  If you do enough searching online for the model, I'm sure you'll find the kind of thing he'll need to make the repair and it should make his work a lot easier and faster and result in a better repair.

https://i.imgur.com/bu9faD7.png

I'd advise against trying to separate the plastic and metal frame.  Often those things aren't designed to dismantled and then you will have bent, cracked, or shattered plastic which won't ever go back together again.  I'd cover the plastic with tape and plastic sheeting (plastic bags, saran wrap, anything like that can be improvised to work), and then you can resurface the metal (dry sand, wet sand, spray coat, etc.) without hurting the plastic.  As long as the metal sheeting isn't too thin to take aggressive cleaning, you really can't hurt any plastic that's taped off or sufficiently covered or any of the metal you're working on: that's how detailers and body shops handle repainting or resurfacing car metal, they cover and tape off the plastic headlights, rubber gaskets, and glass and then they can work as much as they need on the metal sheeting of the car.

I would also guess that your rubber contacts are fine based on the ones you showed.  In my experience the rubber surround tears before the contact pads wear off, and if anything was torn, you'd have seen it already (that kind of damage is very obvious); so, odds are very low that there's anything wrong there.

You're looking for a "Roland F-90 Service Manual" and I can't find any online for sale or download either at the moment.  I'd recommend posting to the PianoWorld forum asking specifically about the circuitry of the F-90 and that you can't find that service manual, because somebody there is bound to know the answer or have a copy of that service manual.

White lithium grease lubricant sounds like a good choice for this, I use it a lot, and it should work well.  It's easy to spray/apply too much, so start with a little bit and slowly add more if needed.

If you can go with Teflon (PTFE), definitely do that.  White lithium grease is usually best for heavy-duty applications like garage doors where a lot of metal is touching a lot of metal, and white lithium is pretty good at repelling dust problem but it does "gum up" over time.  Silicone based/teflon lubricants are my go-to for anything else, especially hinges, and it makes especial sense since you're inside a small space where there isn't a lot of pressure.  PTFE is the best all around (except for machinery, etc.).  I was going to suggest PTFE, but I thought White lithium was the only option.

You can leave the rubber contacts that have been pulled away "floating" in place, or you can use a very small amount of a light rubber to plastic adhesive to reseal it.  You might even be able to gently apply enough pressure to it for it to stick again.  I'm guessing that the used some sort of "ribbon" of double-sided adhesive applied by a machine, and then the contacts were placed on top of that either by hand or by machine, which is why the adhesive strip continues to the very edge of the circuit board.  I don't know exactly what product would be best for that.

An update of my odyssey:

-The cell phone technician who fix PCB told me the work would take too much time for hin, and he could not do it for me. My PCB was also way longer than his cel PCB stand in his working table with microscope. He recommended a friend with similar technical skill for PCB repair in tiny circuits of cell phone. There are just two in the city that do it, delicate tiny line repair, as long as I know, and his friend is the second one.

-This second guy accepted, as he had some experience with other eletronics and not just cell phone's PCB. But the price was a bit high. Well, considering the price of a modern equivallent of Roland, fix it would cost maybe 1/20 of price of buy a new one. Probably worth to fix.

-I found other technical assistance, one who fix organs and digital keyboards in my city, but they do not recreate oxidated tiny lines on PCB.

-Then a I found another digital keyboard & organ technical assistance, but not in my city, and he told me that fix tiny lines in PBC it's routine for them. He send me a video of one PCB line repair. Unfortunately I didn't liked what I saw, since looked like tin alloy repair, instead use 0,1mm copper wire, and it wasn't very precise. My PCB have a deffect that it's in 5 tiny lines or more together, one very close to another, difficult. I asked about prices but I probably will not accept.
Shipping on Brazil it's a absurd. Even if I send just the PCB it will have some cost, plus shipping back. He said that it's better to send the whole keyboard to be able to test, after fix PCB lines. But it's heavy (27kg / 59,52 pounds), it such shipping may cost close to the PCB repair.
They once in a while in the year trip to my city to get work repair here, but it may take months to they get here again.

Suggestions???
By the way... What glue should I use to fix a cracked white plastic key? It cracked in the top, where it fit to the metalic pin holder.

Well, it's very old, I bought already used many years ago. Unless some newer models use a very similar key contacts circuit board, also workable for this of mine, I suppose they no longer have how replace it by a new set.

The fact I performed disassemble and cleaning, probably will reduce the cost, compared if I would let them performe everything. Anyway in my city the service able to open and clean digital pianos do not fix PBC tiny lines, and the technician able to perform tiny PBC do not open or clean digital music instruments.

Sometimes I feel I'm in a pseudo jungle.

Edited: I researched about prices of similar (but not up to use in my DP) Roland DPC for key contract, and just one board (it's 3 in general) would cost similar to the repair of my boards with the technician who fix cell phone PCB. So, even if I could find a so old key contact circuit board to fit to my DP, the price of 2 (one of mine it's almost intact with just a dark dot in a line) or 3 boards woud be considerable more than repair it skilled technician .

I felt I need to replace some buttons like that bellow, but a lot of contact cleaner and press in press out, in about 3 days, fixed all (at least for some time, maybe months) to work almost perfect or perfect (most buttons):

SOLVED... With my contact board in hands, and watching this video of a Roland RD-700 repair, I saw the contact circuits are similar drawing to the one of my F-90, but the connections, between one board to another, are indeed different (different positions).

https://www.youtube.com/watch?v=1Z_pYY129Ew

Or am I wrong?
I judge based in the  black vertical line with silver squares on top and botton. The circuit of my F-90 are look like but the board of my F-90 have the black vertical line in the left side, and not in the right side like the video.

But I bet the seller put a high price intentionally, since I was looking for a specific model.

Wow! I've been following this thread since the beginning. As a now long retired electronics technician, my recommendation is to replace the boards if you can. Given the size of components and circuits these days, or about the size of ants and ant legs, I no longer make repairs myself because I no longer have the motor skills and the eyesight to make a successful repair, but it was a rewarding job troubleshooting and repairing circuit boards when I could do it. The alloy color you saw with the soldering of the copper wires is normal. Solder is in fact a silver-colored material and there is no masking material placed over the solder-joints.

The cost may seem high, if you can get them at an acceptable price, however, look at it this way the amount of time spent cleaning, repairing, and risk of additional damage, is a lot more than what it cost to replace the boards in the long run. This is called the return on investment, or ROI and basically boils down to how much you spent versus how much you'll get out of it in the end. In this case, it's a matter of how much the repairs and faffing around cost you timewise and money-wise compared to a new board that will work right off without worry if the parts are going to hold up.

The issue I see is that the repaired boards may work for a while, but there are circuit traces inside the boards as well that may have cracked. What this means is that your surface repairs will fix those torn traces, but where the surface traces connect to the various pins and holes, there could be other cracks and broken traces inside and with playing and circuit board flexing the other traces will crack inside the board. With issues like this, you'll forever be tracing, troubleshooting, and never, ever, ever repair the problem 100%.

One more note regarding electronics. Never use a household vacuum cleaner to suck out the dust and dirt. A household vacuum cleaner isn't grounded and that can cause static electricity to zap your electronics inside the digital piano. This goes for computers too. The recommendation is to use canned air, or for a more-eco-friendlier approach use a "Rocket-Blaster" type bulb. You can find these at a photography store, or on the web such as at Amazon or B&H photo. They cost about $10 US for these and they work well.

I don't know what plastic they use. Talk to the Roland tech, or another piano technician about the key. They should recommend the kind of glue needed. The problem is if the wrong glue is used, it will either not stick at all, which is a good thing, or worse it could melt the plastic and destroy the key completely. I had that occur with something else, not a piano key, and i ruined the item with the glue which turned everything into mush.

Your PCB technician is doing it the right way. The epoxy or resin over the repaired areas will prevent things from landing on the surface and shorting out the connections. In my old days as a tech, we would use some green gloopy stuff for that. I don't remember what it was called, but it looked similar to the stuff on the circuit boards I repaired. This may be because this was a commercial product and the company wanted the boards to look right.

It is possible for things to not work inside the circuit board. Let me explain. The circuit boards are no longer single-sided, meaning like the very olden days circuits were only on one side with the components pushed through and soldered to the pads. This is still used for simple things, but for more complex circuits, such as computer motherboards and digital pianos, they need to fit a lot more circuits in a smaller space. What this means is there are circuits inside the board as was well as on the surface, and on top of that, there are layers upon layers of circuit paths all over. Multilayer boards can be a few mm thick with various traces going every which way as needed.

The problem is when there's a crack or pull, there's a possibility that the crack has affected more than the top-most or surface circuits. I have seen multilayer boards with no apparent problem, but due to flexing the board inside the computer case, very fine cracks occurred on the inside of the layers causing weird things to happen such as intermittent failures. With ripped circuits, it's possible that the interconnections between the layers is damaged when an upper layer is torn. Remember, these circuits are only 1/2 mm thick if that and are very delicate.

With that said, I would as you say here talk to the Roland tech about this. He can recommend what to do, hopefully with this and the broken key. I wish you a lot of luck with this.

As far as the glue, you want an epoxy that is listed as safe for any plastic-to-plastic bond, which it should say somewhere on the bottle.  Find a small, hidden, unused area on the key you need to repair and put the tiniest amount of the epoxy onto that surface.  Wait a few hours or overnight, and if it hasn't damaged the key, it will be safe to use for the repair.  When making the repair, use as little glue as possible.

I'd avoid many of the Gorilla Glue or Superglue get-anything-to-stick-to-anything sorts of products, because those tend to have stronger chemicals that will denature the plastic since the company isn't sure what you will be gluing to what so they put in as many helpful ingredients as possible.  So products that have long lists of metal-to-plastic, metal-to-glass, glass-to-glass, etc. are may be more likely to harm your product than one that is plastic-to-plastic only (but that can also depend on the brand).  You can also learn a lot about what additives that could harm plastic are inside a product either from a google search; if you can't find a lot about ingredients look for something like an SDS data sheet about a product, which often have to list many or all of the ingredients even if the company considers that to be largely proprietary.

If I am not mistaken, I think it's the same action as in my FP-80 which I really like. I still prefer it to the newer Roland actions. FWIW, my wife, who is a trained pianist quite likes it too. The "ivory feel" refers to the texture of the keys (still plastic) which is less slippery than standard plastic keyboards found on many synths and digital pianos.

Ah, sorry, I should have checked better. From what I read now, both G and S have escapement (they both belong to the PHAIII family), but S is considered superior (and in fact G was used in less expensive models). Of course, you should try for yourself if at all possible. As for Kawai vs Roland, it is mostly a matter of personal taste. I know Phil Best has said that recent Roland actions are closest to a Steinway action...FWIW.

PS Still a mystery to me, after reading through pages and pages of Roland specs (!): I still don't know if the PHAIII-Ivory S (like in my FP-80) is a Graded Hammer Action. It is not mentioned in the description of the FP-80 (and not FP-90 either) but it IS in the specs of its predecessor FP7-F. Could it be that they abandoned GHA starting with FP-80?