Baby Grand Piano

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pianomike1957

Joined Jan 1, 2013
24
Here's why I think its something simple, ie like that battery..... the guy in England won't share any info, I've read quite a few posts from people with the same problem and I think he's got a little gold mine going having figured out the secret.

One thing he does emphasize, and I hope I didn't make matters worse, is static electricity damage. But I haven't been "shocked" in awhile except by my dog when she's in the car, so hopefully I didn't fry it worse.

I'm gonna read the transistor checking link above and pursue this battery too.

You know, I left this board with a TV/computer place for three weeks and they never once mentioned that battery and I was in there like twice a week checking on it. I mean they were nice, but they basically said they can't fix it. At least they didn't charge me. I offered but they were cool. They seemed to only want to "change boards", which I'm sure is quite lucrative if its a common item like a sony tv.
 

Thread Starter

pianomike1957

Joined Jan 1, 2013
24
You guys have given me enough stuff here to keep me busy for a few days. If I get this puppy fixed I'm buying everyone pizza.

The real clincher here is.... if I can't fix it, I'm gonna try to tie the keyboard inputs into something else that can read them, even if I have to use a dedicated laptop, and just bypass all the synthesizer stuff. I really like this thing because its a full keyboard and the weighted keys are awesome. Plus its really pretty. I have a Korg M-50 sythesizer that takes MIDI inputs, but my skill level, at least for now, is way below what it would take to do this. I just hope its that darn battery lol.

I'll keep answering responses whilst I delve. Thanks. By the time this is done, I'll be a senior member. BTW, don't when capacitors go bad they "pop" they're top? I gotta read up on checking them too.
 

Thread Starter

pianomike1957

Joined Jan 1, 2013
24
On the Ghana link, ..... I feel ya.

The only way, for me at least, to make a dent in this world's injustices, is through music. All you can do is try your hardest.
 

Thread Starter

pianomike1957

Joined Jan 1, 2013
24
Hey sure enough, that battery is bad. (i think). Its only reading .4VDC Its supposed to be 5.5VDC. Could this problem really be this easy? I mean if the battery dies, the whole damn piano dies? This battery is not removable either. I have to use the soldering iron on back of the board. Is this a common practice on these type of boards?
 

takao21203

Joined Apr 28, 2012
3,702
Maybe it is a super capacitor. Show the label on the forum.

You can try to twist it off on the top side, and solder wires.

Desoldering from epoxy boards can be difficult even for experienced people. You need a 50W iron + high temp + apply fresh solder.

Before removing, power up the board, and measure again the voltage.

Also these transistors like you call them are likely diodes, or MOSFETs. You could bend up the small legs, and measure them. For a MOSFET you just need a LED, a resistor, and 12V supply. For a diode, multimeter.
Of course the MOSFETs either could be P-channel or N-channel.

Also measure the voltages on the two large capacitors.

If there is something on the screen, as I say, likely a configuration error, or FLASH corruption.

Maybe the keyboard has some kind of serial bus, and one device is not responding + no error checking exists in the firmware.
 
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GopherT

Joined Nov 23, 2012
8,009
The transistors are bipolar PNP (7 Amp, 40 Volt, hfe of 60 to 90).
Link to datasheet is on first page of this chain.
 

takao21203

Joined Apr 28, 2012
3,702
OK it is a super capacitor. The smaller rectangle chips in the upper right are 2x FLASH chips very likely.

That board does not look like having a cost of $10,000
Some 100 $ for the chips, at maximum.

The resolution is low, a better than nothing picture.
It is at least required to see the labels on the chip.

The large chips are all Technics specifics, no chance to find them anywhere except from Technics/Panasonic. Usually, PCB revisions are abandoned every few years.

Some clever guy could indeed take off the FLASH chips from a working board, read them out, write them to new FLASH chips, and exchange on your board.

If FLASH corruption is the issue.

I would try to contact Panasonic by all means, and see what they have to say. They may know the PCB, and issues arising in the circuit.

The FLASH chips are old technology, just SOIC chips, not difficult to remove/resolder.

I saw vietnamese even removing BGA chips from mobile devices :) (in a video).

Do you have a transistor tester if you want to check out the power supply transistors? If not, it is easy to build one.
 

Thread Starter

pianomike1957

Joined Jan 1, 2013
24
Thanks Tak. Yeah the board isn't 10K, I was talking about the whole piano. Even at that, I saw one on ebay go for like $3400.

So can I assume that since this is a super capacitor, not a battery, that more than likely this is not the problem here?

I really don't think (hope) its a corruption issue since sometimes, when its all put together, on power-up, if I do it several dozen times, everything appears to work, ie the menue and the buttons appear to work fine. No sound though. But it would seem if it can make it that far on loading up, even once, that the flash etc is still there. If it wasn't, I would never get to that menue, right? But like I said, most times on power-up its just a blue screen. I'll post more photo's of this if it helps lol .


On the first page of this thread, as noted, are the specs on the two transistors. Does anyone have a link to someone who sells these kind of components in small quantities? I just have a feeling that's where my problem is, and just for fun and grins, order them and try. I don't have a transistor checker but I'm sure if I look, I'll find the plans here somewhere to build one. I do have a real nice nice digital Volt/ohmeter though. I guess I should test them before ordering.

Anyway..... gotta run.... I'll check back later. :)
 

BReeves

Joined Nov 24, 2012
410
As a stab in the dark I would check to make sure all the clocks are running but you really need a scope to do that. I saw 3 crystals (oval silver things) which in a processor circuit are usually setting the frequency of a clock. If the processor isn't receiving a clock it might just power up in some weird state like the symptoms you are describing.
 

takao21203

Joined Apr 28, 2012
3,702
FLASH corruption does not mean the FLASH chip is totally defective.

It is enough for one bit to fail. The software will hang up.

Sometimes maybe just a few bits fail, while most of the time, a few more bits fail.

This could explain why the software sometimes can start up.

But because there are still some corrupted bits, it can not work as intended.

It could have other reasons as well.

There might be serial EEPROMs on the board, or other serial devices.

There might be a problem with one or more bits in the RAM (Volatile memory).

For a replacement PNP, you don't have to use the same model.
I guess they don't max out the transistors on the PCB.

So if it is a PNP power transistor, you can replace it with nearly any other DPAK PNP, with a few more Amps capability, or a few less.

Maybe there is a failed solder joint or contact oxydization issue. It's worth trying to use a cleaner spray for contacts, and inspect the solder joints with a magnifier glass.

EEPROMs are small 8-pin chips. Every CD or DVD drive is using these for region lockout :)
 

takao21203

Joined Apr 28, 2012
3,702
Thanks Tak. Yeah the board isn't 10K, I was talking about the whole piano. Even at that, I saw one on ebay go for like $3400.

So can I assume that since this is a super capacitor, not a battery, that more than likely this is not the problem here?

I really don't think (hope) its a corruption issue since sometimes, when its all put together, on power-up, if I do it several dozen times, everything appears to work, ie the menue and the buttons appear to work fine. No sound though. But it would seem if it can make it that far on loading up, even once, that the flash etc is still there. If it wasn't, I would never get to that menue, right? But like I said, most times on power-up its just a blue screen. I'll post more photo's of this if it helps lol .


On the first page of this thread, as noted, are the specs on the two transistors. Does anyone have a link to someone who sells these kind of components in small quantities? I just have a feeling that's where my problem is, and just for fun and grins, order them and try. I don't have a transistor checker but I'm sure if I look, I'll find the plans here somewhere to build one. I do have a real nice nice digital Volt/ohmeter though. I guess I should test them before ordering.

Anyway..... gotta run.... I'll check back later. :)
As I wrote, measure the voltages on the super cap + the two big caps on the bottom, some minutes after power up.

Yes any photo will help.

And you can find many DPAK PNP transistors on eBay.

At first, maybe look at Farnell, by the parameters.
You narrow the search by PNP, and DPAK case.

Then you look at minimum Amps, and voltage capability.

The most common model numbers, you maybe will easily find them on eBay.

I have one type of power PNPs here, DPAK case, they may work :)
Costed me almost nothing.

But I have not looked yet if the pins are the same. I used one of these once for a small SMPS circuit. 35V input, and adjustable output!

A transistor tester is simple. You need a LED, and a small battery for instance 9v, one LED resistor, and two adjustable resistors (pots, 50K or 200K).

One pot is used between + and - for the base voltage. The other is inlined before the base, to regulate the current.

You can then turn the pots, and see the transistor turning on.
 

Thread Starter

pianomike1957

Joined Jan 1, 2013
24
You the man Takmo.... We'll get there. I'm havin' all kinds of good luck today. Sending some your way. Are you really in Ireland. I've got a weee bit of the mick in myself. Good people those Irish folks. Any opinion on Notre Dame vs Alabama. Whilst I claim from the emerald island, I also know how tough the SEC can be in college football. My guess, Notre Dame gets creamed.
 

takao21203

Joined Apr 28, 2012
3,702
Yes I really live here. During the past ten years, all sort of technology arrived here. We have now self-service supermarkets, self-service banks, wireless internet, a Tram network and a port tunnel, soon maybe even a subway.

And there is always at least one shop here in Dublin which is open 24 hours.

By the way Takao is a japanese name. But people don't have difficulties using it.
As far as I know it means as much as "Eagle man".
And it is the main character from Beyblade Bakuten Shoot. The original Beyblade,
not the new Beyblade Metal Fusion.
 

Thread Starter

pianomike1957

Joined Jan 1, 2013
24
Oh yeah? Well, what about that Notre Dame game? lol. I'm laying down some U.S. buckarollas on it . Re technological infiltration...... we live in interesting times. The States are a few years behind in all the "we can spy on you at anytime" technology. Albeit most of it was created here. (Why is it when I post here, I can't have breaks, ie spaces for paragraphs. Like blank lines between seperate subjects). I must have a setting wrong.
 

Thread Starter

pianomike1957

Joined Jan 1, 2013
24
Oh yeah? Well, what about that Notre Dame game? lol. I'm laying down some U.S. buckarollas on it . Re technological infiltration...... we live in interesting times. The States are a few years behind in all the "we can spy on you at anytime" technology. Albeit most of it was created here. (Why is it when I post here, I can't have breaks, ie spaces for paragraphs. Like blank lines between seperate subjects). I must have a setting wrong.
(Why is it when I post here, I can't have breaks, ie spaces for paragraphs. Like blank lines between seperate subjects). I must have a setting wrong.[/QUOTE]<br />
<br />


Igotta figure out this whole forum "quote" thing too.

Its probably my browser settings. I run ad-block and no-script on Firefox. I'll try enabling allaboutcircuits on no-script and see if that works.
 

takao21203

Joined Apr 28, 2012
3,702
Weed prices here are bad. Only topped by Japan.
Guess I don't have much an idea about Notre Dame.

Plant life here in Ireland is weird too. It stops in September/October, then some plants resume in December and January already.
 
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