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First - congratulations for fixing the board

I think the only affected ICs are the static RAM chips. Everything else should be in order.
I looked through the preset list and service manuals of both RP200 and RP220.
The preset list is not exactly the same, but the service manual suggests the same Wave ROM modules, 104041 * "Wave98" and 104023 * "ProWave3". The Sound Program List is also the same.
The "Preset" is just a combination of sounds/keyboard splits/layers/effects, I think.

Just one thing - how are connected the jumpers J2-J6? Now with the RP200 pre-v2 firmware, they should be probably all in L position.

Honestly, I have no idea why some sounds do not work.
Maybe there is still some shortcircuit on the traces. The affected numbers are high and mostly grouped together, maybe some address line is shorting to higher one and the sound processor reads blank data instead of the correct sound samples.

Yes, the preset list is different in the owners manual of RP200 and RP220, but not different in the pianos. The RP200 has the same presets in real. And you are right, the presets are combinations of the 64 sounds from the Sound Program List, with differnet settings (effects, reverb etc.). The pure sounds from that list can be tested by pressing Perf. Edit button, and choose with +- buttons. The Sound Program List is the same in the real, and in the owners manual too, and from sound 1-48 those are the same in RP90 too. RP90 doesn't have the Wave3 ROM module, and doesn't have the sounds 49-64.

I made an experiment: took off the Wave3 ic, and I didn't experience any change in the sounds. The wrong sounds are sometimes good until some key-pressing, sometimes theres a digital noise, sometimes just no sound. I made a recording of that: RP220 wrong sounds

It looks like some part of these sounds is stored in the wave98, and the sound 61,62 completely (these two work without fault). The phenomenon is the same with the Wave3 on the board, so it seems like it is completely dead. But I don't know why, these sounds are wrong since the very beginning, when I still replaced only the two RAM modules. It may got something of the acid, but now the connections are ok, I checked it several times, and I didn't even found any shorts. The only fault that I found is the C25 capacitor (100nF) next to the wave3's leg 22 (+5V), it's the power supply filter capacitor. I measured the capacitence of that, it is 180pF. I replaced it, but there isn't any change. Maybe that killed the ic? I've checked the power supply voltages on wave3, those are ok. I'm going to check the voltages on all the legs of it, and compare it to the other cpu board. And maybe put the wave3 from RP200 cpu board to RP220's. If it will work, than I can be sure that the ic is wrong. But I wouldn't like to spoil the other board too Maybe just first replace again the two 1Mbit ROM modules.

About the jumpers: first I left them in the original position (LLHLL). During the boot the lcd was empty, it didn't show the GEM logo and the RP220. But after the boot it worked fine, without any failure. Then I changed the jumpers to RP200 setting (LLLLL), and I use it so since that. With this setting I have the GEM logo at startup, and it shows RP200.

I wouldn't solder the working wave ROM to the suspicious PCB. A little too much risk.
At least, I'd buy an EPROM/flash ROM (something like M27C320 in SO44 package) and program it with the ProWave3 ROM content*, then use the EPROM for experiments.

*GEM manufactured some RP*00 boards with "factory wrong ProWave3 ROMs" - they accidentally swapped the data bytes (low/high 8 bits from 16) in production. They called it later "Limited edition" and used different PCB for it, with swapped data lines. It's described in the service manual for RP100-150-200, page 17.
Question is, if they installed the chips only in these "limited boards" or there was some service recall for other boards as well...
If You swap the high and low byte in sound sample, it could sound like some strange noise.
Maybe You have the wrong ROM and just didn't checked these sounds before the failure?

According to schematics, the only connection difference between the two wave ROMs are the ChipSelect lines. If the ProWave ROM doesn't get the CS then it might not respond.
But these lines are too far away from the battery to be affected, I think.
The whole sound generator part has own data and address lines, going between the Wave ROM ICs and Sound Generator ICs.

Maybe You happened to have the "Limited bad Promega3 ROM"
Then get the flash, read the ROM, swap data bytes and put back the flash with the modified content.
But even then the board should not sound the same, when the chip is removed. It could make some noises, reading samples "out of thin air", but with the chip the sound should be consistent, even when bad.
I'm puzzled.

At first, if anyone will be in a trouble like me, I uploaded the eprom file: gem_rp200_rp220_grp300_am29F800bb_firmware_v1.02.bin

I've checked that part in the service manual. It says that the limited edition cpu board has the code 310661, and the wave3's code is 761189. But my cpu board has the normal code (310603/1), and the wave3 on it too (761172). I bought this piano as it was wrong, so I don't know, if those sounds were working before that. But I have the phone number of the previous owner, I'm going to ask him.

I made some measurements. I have no oscilloscope or logic analyzer at home, so I just checked the voltages on the legs of wave3 with a multimeter in dc mode. I switched to one of the non-working sounds, checked and noted the voltages on each leg in normal position, and when pressing a key. I compared the good and the faulty boards voltages, and to my surprise there were no any difference. Chipselect line works fine too. So it looks like the wave3 sends data, but maybe not the correct data? Very strange. Maybe the fault is somewhere else? But then, why aren't there any changes in the sound, when the wave3 is not on the board?

And I realized another strange thing: If I play slowly and I press always just one key at the same time, and release the key before pressing the next, the sounds are ok. Every sound's every note is ok. But if I play faster, and the notes are not separated, or I press more keys at the same time, the sound gets noisy, or completely dumb. But only at the wrong sounds. I have no idea yet, but I don't know too much about the working of microprocessors and how they read memories.

I think my eprom programmer can't read the wave3. Searched on the internet, how could I read that, but I haven't found the answer.

Oh, and another thing: I've replaced the two ram chips again, but there's no any change.

Hello to all,
my Stepfather bought an dead old RealPiano RP2.
This model as the battery leaking problem.
I have found 2 cut traces and i have repaired, when i turn on the piano, the lcd display turns ON but nothing works!
If someone can help, i will be very gratefull
Here some pictures (ignore the red cable that is disconnercted) :



If this is the wrong thread, let me know and i will open a new one

Not much to go on. The old chestnut of leaking caps, but I would want to know why there was '2 cut traces', as that may be symptomatic, or maybe not.

The traces were corroded by the leaking battery, like mentioned on the first post of this thread.

If the board is fully repaired and there are no other breaks or shorts, I'd replace the two static RAM chips.
Somehow they get damaged in case of battery leak, probably beacuse they're the only ones powered through the battery circuit.
Probably, when the voltage on adress/data pins is suddenly much higher than supply voltage.

The correct types and possible replacements are mentioned earlier in this thread.

And it looks like the GEM USA site just went offline
Fortunately, the service manual can be found here - http://www.shema.ru/cd/us/2/data/rp2.pdf

From the photo that i posted, can you tell me which chips are the rams ?
Your pcb is different from mine.
Thanks

The two in the upper left corner, marked SEC KM681000BLG-7

Thank you for your time.
Can you tell me if i can use these ones :
http://www.ebay.fr/itm/301833734760?ru=http%3A%2F%2Fwww.ebay.fr%2Fsch%2Fi.html%3F_from%3DR40%26_sacat%3D0%26_nkw%3D301833734760%26_rdc%3D1

The piano cost 60 euros, i don't wan't to spend 50 euros for 2 chips.
Thanks

No, they have different size (4 times larger capacity) and different pinout because of that.
Read the thread, the replacements are like 1.50 EUR a piece.

Ok thanks for the tip !
do you have a link for the 1,5 euros a piece ?
NVM, just found and order.

Hi! My name is Lucio, from Spain. I recently acquired this piano GEM RP90 (Same as Michael), and it has the same problems as the others with the battery, but I think mine is far worse than the others. Do you think I could save this board and the piano?

Looks really bad now. Like some traces disappeared, but maybe (hopefully) it's only dirt and corrosion.
I think it's doable.
First step would be to unsolder the flash and two RAM ICs (the RAM will be for 99% sure broken so order new ones already), then clean and inspect the board.
Then trace repairs, and soldering back the flash and new memory chips.
The service manual is here http://www.shema.ru/cd/us/2/data/rp90.pdf

My board wasn't very pretty at the beginning either, on the first photo it is already after cleaning and applying some new tin on the solder pads and traces.
Good luck with the repair

Thanks for the answer Michael!
I think the AMD thing (I think it's the flash) is broken, as the contacts are not good looking. If the flash is broken, what can I do? Does this mean it's all lost? Is it possible to rewrite the firmware in a new flash?
I wanted to use this piano as a master midi, so I don't really care about the sounds. Is there any way to get the midi to work without the main board?

I've seen this GEM Piano Board on eBay with similar connections as our board, but it isn't the same, could it be my last solution if I can't repair it? http://www.ebay.es/itm/GEM-Generalmusic-Piano-PRO-1-CPU-Platine-761132-315093-neu-Ersatzteil/272254928612?_trksid=p2046732.c100040.m2060&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160516100611%26meid%3Da1a40a488a024e078aef95a42138c5f9%26pid%3D100040%26rk%3D2%26rkt%3D4%26sd%3D252093800420

Thanks for your attention!

I think "the AMD thing" is okay, only the traces around need to be repaired.
And You're right, it's the flash with firmware. In rather unlikely case it's bad, I have the firmware and You can flash a new chip.
In confirmed repairs, always only RAM died, probably because of short-circuit through the battery. And only RAM is battery-backed.

Unfortunately, without the mainboard, nothing works. MIDI goes in and out from the main CPU (the Hitachi H8 chip).
The keybed has it's own brain and serial connection line to the H8, so You could use it separately but You will have to reverse-engineer the connection protocol, there is some info in this thread.
So at least You'll need to hook some Arduino to the keybed processor to get MIDI out if the mainboard is out. But I think repairing the board is easier

The Pro1 has different "insides", so I doubt that it's possible to convert a RP90 to a Pro1.

Hi all, specialy Michael aka kumi_27 who is helping us to repair our leaked pianos xD

I'm registered because my RP 150 has the same problem and I found this topic to try to solve the problem.

In my case is a GEM RP150 and im trying to find the compatible rams for it. I dont understand lot of electronic an because of that i'm here asking for help.

In my piano the rams are SEC Korea 938A KM681000CLG-7L . What the 938A numbers means? I found some km681000clg-7l rams, 5pc about 15$, but with another "sec korea" numbers (sec korea 950A, sec korea 810A...). and dont know if they are compatible with my rams...

i'm a bet lost in this issues, so i appreciate any help you can give me.

Thank you very much

938A could be a lot number or something. Not important.
KM681000CLG-7L is the type and it describes the internal organisation of the chip and its speed.
Service manual - http://www.shema.ru/cd/us/2/data/rp100.pdf - says, it should be HM628128LFP5 SOP 1Mbit Static Ram Ta=55nS - or compatible,
because they had different ICs even at the factory.

So I'd say, You should search for KM681000CLG-5L chips, the faster ones with ~55ns refresh.
Or other mentioned here types from other manufacturers (also the 55ns versions), because they're interchangeable.

Good luck with the repair

Hi again,

I was busy with the repair of the board... It tooks more job than i expected.

I bought the rams recomended by Kumi_27,
I repaired the broken conexions, a electrician friend help me with the rams soldering... but didnt work






The error is the same from the beginning, no changes from the first error. here a foto; Only few lights and nothing in the display.




Thanks again for the help Kumi_27,

Ideas for my next step? maybe buy another piano....