Pianotech

My wife recently purchased a PianoDisc piano.  This is from 1994 and labeled PianoDisc on the fallboard(?) and soundboard.  Some may have different opinions, but it's a win-win for us.  My wife plays and I'm an electronics technician - so my questions will be largely around the PDS128 system.

I've managed to find various manuals including a service manual, but still have some questions.  

Here is what we have:

1. We do not seem to have the TFT option but not sure
2. The control unit says only PDS128-S and is at SW version 4.6, and it lists Orchestra as an option(?)
3. The piano has two AR powered speakers mounted and connected to the PDS128
4. The main box underneath has the driver boards (pedal cable, PS, PDS connector) and Midi ports and a record light, power switch board at other end
5. The power supply is the aluminum version
6. All functions of the system except the sustain pedal/solenoid are working.
7. I have a pile of diskettes provided with the piano and all read and play - but I do not have a factory test diskette

Questions:

1. What does the Orchestra option do?  I understand the accompaniment function.
2. The sustain solenoid is not working.  I checked for voltage to the solenoid while playing a diskette and nothing.  I pulled the connector and measured the resistance of the solenoid and got 6.1 ohms. Also, when doing the Sustain Pedal Strike Force adjustment via the PDS128 programming, we get a "Byte Failure" at the end of the Sustain Pedal Hold Force test.

What I've done:

1. Did initial tests above with no changes
2. Pulled main power supply and changed all capacitors, fixed a few previous repairs and got the fan working.
3. Checked all cables for continuity
4. As an aside, someone had installed a small audio isolation box on the audio outputs to the PDS128, apparently due to hum.  I also had pulled the AR speakers and found several bad caps (one shorted and one open).  All the caps in the AR speakers were starting to leak - so caught that just in time!

So - a big list of topics for a newbie here.  Hope you folks don't mind.  Any assistance is appreciated!

Mark

------------------------------
Mark Roberts
Farmington NY
------------------------------

My wife recently purchased a PianoDisc piano.  This is from 1994 and labeled PianoDisc on the fallboard(?) and soundboard.  Some may have different opinions, but it's a win-win for us.  My wife plays and I'm an electronics technician - so my questions will be largely around the PDS128 system.

I've managed to find various manuals including a service manual, but still have some questions.  

Here is what we have:

1. We do not seem to have the TFT option but not sure
2. The control unit says only PDS128-S and is at SW version 4.6, and it lists Orchestra as an option(?)
3. The piano has two AR powered speakers mounted and connected to the PDS128
4. The main box underneath has the driver boards (pedal cable, PS, PDS connector) and Midi ports and a record light, power switch board at other end
5. The power supply is the aluminum version
6. All functions of the system except the sustain pedal/solenoid are working.
7. I have a pile of diskettes provided with the piano and all read and play - but I do not have a factory test diskette

Questions:

1. What does the Orchestra option do?  I understand the accompaniment function.
2. The sustain solenoid is not working.  I checked for voltage to the solenoid while playing a diskette and nothing.  I pulled the connector and measured the resistance of the solenoid and got 6.1 ohms. Also, when doing the Sustain Pedal Strike Force adjustment via the PDS128 programming, we get a "Byte Failure" at the end of the Sustain Pedal Hold Force test.

What I've done:

1. Did initial tests above with no changes
2. Pulled main power supply and changed all capacitors, fixed a few previous repairs and got the fan working.
3. Checked all cables for continuity
4. As an aside, someone had installed a small audio isolation box on the audio outputs to the PDS128, apparently due to hum.  I also had pulled the AR speakers and found several bad caps (one shorted and one open).  All the caps in the AR speakers were starting to leak - so caught that just in time!

So - a big list of topics for a newbie here.  Hope you folks don't mind.  Any assistance is appreciated!

Mark

------------------------------
Mark Roberts
Farmington NY
------------------------------

My wife recently purchased a PianoDisc piano.  This is from 1994 and labeled PianoDisc on the fallboard(?) and soundboard.  Some may have different opinions, but it's a win-win for us.  My wife plays and I'm an electronics technician - so my questions will be largely around the PDS128 system.

I've managed to find various manuals including a service manual, but still have some questions.  

Here is what we have:

1. We do not seem to have the TFT option but not sure
2. The control unit says only PDS128-S and is at SW version 4.6, and it lists Orchestra as an option(?)
3. The piano has two AR powered speakers mounted and connected to the PDS128
4. The main box underneath has the driver boards (pedal cable, PS, PDS connector) and Midi ports and a record light, power switch board at other end
5. The power supply is the aluminum version
6. All functions of the system except the sustain pedal/solenoid are working.
7. I have a pile of diskettes provided with the piano and all read and play - but I do not have a factory test diskette

Questions:

1. What does the Orchestra option do?  I understand the accompaniment function.
2. The sustain solenoid is not working.  I checked for voltage to the solenoid while playing a diskette and nothing.  I pulled the connector and measured the resistance of the solenoid and got 6.1 ohms. Also, when doing the Sustain Pedal Strike Force adjustment via the PDS128 programming, we get a "Byte Failure" at the end of the Sustain Pedal Hold Force test.

What I've done:

1. Did initial tests above with no changes
2. Pulled main power supply and changed all capacitors, fixed a few previous repairs and got the fan working.
3. Checked all cables for continuity
4. As an aside, someone had installed a small audio isolation box on the audio outputs to the PDS128, apparently due to hum.  I also had pulled the AR speakers and found several bad caps (one shorted and one open).  All the caps in the AR speakers were starting to leak - so caught that just in time!

So - a big list of topics for a newbie here.  Hope you folks don't mind.  Any assistance is appreciated!

Mark

------------------------------
Mark Roberts
Farmington NY
------------------------------

Hello Mark,

What you have there is what we called the Blue Board system.  All the circuit boards are blue, and that system was updated in 1997 to the Silent Drive (Green Board) system.  And as you already know, it's fairly old and it's susceptible to issues.

The Orchestra option enables you to play floppy diskettes that have the background/orchestration.  If you look at each diskette, every one has a 4 or 5 album number (PD9004 or PD13002).  If it has 4 numbers, that album is acoustic only (piano only).  And if it has 5 numbers, it will have some kind of background music.  And since you have speakers installed, I'm 90% sure you have that option.

The orchestra option also enables you to play different sounds, like a keyboard, as you play the piano if you have Record (TFT) option is also installed. And you do.  The board with the MIDI in and MIDI out inside the rail cover IS called the Record Board and that connects to the TFT under the keyboard.  

For the Solenoid, my guess is the the voltage to the solenoid is bad.  It's very rare the solenoid fails.  Test the solenoid output plug for voltage, if there is none there, the issue is most likely the board.  

For electrical questions, you can contact Brad @ PianoDisc in the tech department.  Be parpared, though, they might completely laugh at you because they stopped supporting that system 10 years ago.  If you need parts, let me know... I have a limited source for blue board systems parts.  I can always look.

My wife recently purchased a PianoDisc piano.  This is from 1994 and labeled PianoDisc on the fallboard(?) and soundboard.  Some may have different opinions, but it's a win-win for us.  My wife plays and I'm an electronics technician - so my questions will be largely around the PDS128 system.

I've managed to find various manuals including a service manual, but still have some questions.  

Here is what we have:

1. We do not seem to have the TFT option but not sure
2. The control unit says only PDS128-S and is at SW version 4.6, and it lists Orchestra as an option(?)
3. The piano has two AR powered speakers mounted and connected to the PDS128
4. The main box underneath has the driver boards (pedal cable, PS, PDS connector) and Midi ports and a record light, power switch board at other end
5. The power supply is the aluminum version
6. All functions of the system except the sustain pedal/solenoid are working.
7. I have a pile of diskettes provided with the piano and all read and play - but I do not have a factory test diskette

Questions:

1. What does the Orchestra option do?  I understand the accompaniment function.
2. The sustain solenoid is not working.  I checked for voltage to the solenoid while playing a diskette and nothing.  I pulled the connector and measured the resistance of the solenoid and got 6.1 ohms. Also, when doing the Sustain Pedal Strike Force adjustment via the PDS128 programming, we get a "Byte Failure" at the end of the Sustain Pedal Hold Force test.

What I've done:

1. Did initial tests above with no changes
2. Pulled main power supply and changed all capacitors, fixed a few previous repairs and got the fan working.
3. Checked all cables for continuity
4. As an aside, someone had installed a small audio isolation box on the audio outputs to the PDS128, apparently due to hum.  I also had pulled the AR speakers and found several bad caps (one shorted and one open).  All the caps in the AR speakers were starting to leak - so caught that just in time!

So - a big list of topics for a newbie here.  Hope you folks don't mind.  Any assistance is appreciated!

Mark

------------------------------
Mark Roberts
Farmington NY
------------------------------

Hi Mark, in addition to Dave's response I'll add that the cable in the action cavity that is unplugged is most likely for the TFT strip.  Exiting from under key 88 (top fat key) is a thin white band of metal  .....  this is a data cable.  It plugs into a very small circuit board that is usually mounted on the hammer rail.  Some techs mounted it on the side of the action cavity.  The opposite end of this little circuit board had the larger grey data cable with a silver end.  This cable makes it's way towards the back of the action cavity and passes through the slot where the key solenoids are.  From there it plugs into the record board previously mentioned.  The fact that you see some cables dangling, possibly disconnected may indicate that the "record interface board" may be missing or damaged.  It's only about an inch by an inch and a half.  When mounted on the side of the action cavity is was prone to breakage when the action was moved in and out of the action cavity.

The earlier PDS units had a separate pedal board located inside the "rail cover" or that long black sheet metal cover that extends from treble to bass under the piano just behind the trap work.  On the pedal board were two adjustments for pedal hold force and pedal strike force.  Usually if the pedal solenoid isn't doing anything it was because the board was bad and needed to be replaced.  Sometimes it was simply because the solenoid was out of adjustment.  Grasp the long aluminum hex nut located on the end of the solenoid plunger and work it up and down.  If there's any movement upwards, that's probably your problem.  Adjust this large nut (and associated jam nut) to eliminate the "lost motion" and you may find your pedal solenoid starts to function again.  Ver 4.6 came out after this unit was born.  The software adjustments don't have any effect on the pedal solenoid.  That is done via the brass trimpots found on the pedal board.  I don't remember the adjustment procedure.  The voltage at the solenoid plug will be dependent upon whether or not the software is activating the voltage or not at any particular moment.

Keep in mind you have a model 128 and not a 128plus.  We commonly called this model the 128 minus. 

The "power" button on the record board when in the off position will cause the control box to light up, read the disk, but not activate the keys of the piano.  Small little bozos typically push this button just to make parents say affectionate things about them.  Sometimes it costs a piano owner a service call to learn this.

AR stopped making the AR570 quite awhile ago.  The only failure I've seen in them is a blown speaker.  One speaker is typically enough sound to overpower the piano.  I usually turn one of them off.

The P/S has fuses inside located in a very difficult place for service.  The 1/2 amp fuse was the one to fail.  I've replaced it with a 3/4 amp (AGC3/4) fuse and have not been scolded by the factory.

The accompaniment sounds (everything but piano) won't be heard unless you have a speaker turned on, hooked up, volume up and have a five digit disk in the disk drive.  Dave touched on this subject.  In the software controls of the control box there's a balance control with a P on one end of the bar and an S on the other.  Start with it in the middle.  The volume of the piano won't track with the volume of the speaker at the low end of things.  You may have to have the overall volume of the piano up to at least a number 10 to get any audio out.  Some of the software with 5 digits has awfully long stretches of music that doesn't have any audio/orchestra, just piano.

Find the default command in the menu and select it.  This will put everything at factory default including putting the balance at the middle.

Test disk?  Uh  .......  oh that one.  If I look long enough I might find it  .......  but currently I don't have the incentive.  I have a hunch it's landfill fodder.

You tested all the capacitors?  How?  You must have some awfully good test equipment.  I'm impressed.

Lar

Hello Mark,

What you have there is what we called the Blue Board system.  All the circuit boards are blue, and that system was updated in 1997 to the Silent Drive (Green Board) system.  And as you already know, it's fairly old and it's susceptible to issues.

The Orchestra option enables you to play floppy diskettes that have the background/orchestration.  If you look at each diskette, every one has a 4 or 5 album number (PD9004 or PD13002).  If it has 4 numbers, that album is acoustic only (piano only).  And if it has 5 numbers, it will have some kind of background music.  And since you have speakers installed, I'm 90% sure you have that option.

The orchestra option also enables you to play different sounds, like a keyboard, as you play the piano if you have Record (TFT) option is also installed. And you do.  The board with the MIDI in and MIDI out inside the rail cover IS called the Record Board and that connects to the TFT under the keyboard.  

For the Solenoid, my guess is the the voltage to the solenoid is bad.  It's very rare the solenoid fails.  Test the solenoid output plug for voltage, if there is none there, the issue is most likely the board.  

For electrical questions, you can contact Brad @ PianoDisc in the tech department.  Be parpared, though, they might completely laugh at you because they stopped supporting that system 10 years ago.  If you need parts, let me know... I have a limited source for blue board systems parts.  I can always look.

My wife recently purchased a PianoDisc piano.  This is from 1994 and labeled PianoDisc on the fallboard(?) and soundboard.  Some may have different opinions, but it's a win-win for us.  My wife plays and I'm an electronics technician - so my questions will be largely around the PDS128 system.

I've managed to find various manuals including a service manual, but still have some questions.  

Here is what we have:

1. We do not seem to have the TFT option but not sure
2. The control unit says only PDS128-S and is at SW version 4.6, and it lists Orchestra as an option(?)
3. The piano has two AR powered speakers mounted and connected to the PDS128
4. The main box underneath has the driver boards (pedal cable, PS, PDS connector) and Midi ports and a record light, power switch board at other end
5. The power supply is the aluminum version
6. All functions of the system except the sustain pedal/solenoid are working.
7. I have a pile of diskettes provided with the piano and all read and play - but I do not have a factory test diskette

Questions:

1. What does the Orchestra option do?  I understand the accompaniment function.
2. The sustain solenoid is not working.  I checked for voltage to the solenoid while playing a diskette and nothing.  I pulled the connector and measured the resistance of the solenoid and got 6.1 ohms. Also, when doing the Sustain Pedal Strike Force adjustment via the PDS128 programming, we get a "Byte Failure" at the end of the Sustain Pedal Hold Force test.

What I've done:

1. Did initial tests above with no changes
2. Pulled main power supply and changed all capacitors, fixed a few previous repairs and got the fan working.
3. Checked all cables for continuity
4. As an aside, someone had installed a small audio isolation box on the audio outputs to the PDS128, apparently due to hum.  I also had pulled the AR speakers and found several bad caps (one shorted and one open).  All the caps in the AR speakers were starting to leak - so caught that just in time!

So - a big list of topics for a newbie here.  Hope you folks don't mind.  Any assistance is appreciated!

Mark

------------------------------
Mark Roberts
Farmington NY
------------------------------

My wife recently purchased a PianoDisc piano.  This is from 1994 and labeled PianoDisc on the fallboard(?) and soundboard.  Some may have different opinions, but it's a win-win for us.  My wife plays and I'm an electronics technician - so my questions will be largely around the PDS128 system.

I've managed to find various manuals including a service manual, but still have some questions.  

Here is what we have:

1. We do not seem to have the TFT option but not sure
2. The control unit says only PDS128-S and is at SW version 4.6, and it lists Orchestra as an option(?)
3. The piano has two AR powered speakers mounted and connected to the PDS128
4. The main box underneath has the driver boards (pedal cable, PS, PDS connector) and Midi ports and a record light, power switch board at other end
5. The power supply is the aluminum version
6. All functions of the system except the sustain pedal/solenoid are working.
7. I have a pile of diskettes provided with the piano and all read and play - but I do not have a factory test diskette

Questions:

1. What does the Orchestra option do?  I understand the accompaniment function.
2. The sustain solenoid is not working.  I checked for voltage to the solenoid while playing a diskette and nothing.  I pulled the connector and measured the resistance of the solenoid and got 6.1 ohms. Also, when doing the Sustain Pedal Strike Force adjustment via the PDS128 programming, we get a "Byte Failure" at the end of the Sustain Pedal Hold Force test.

What I've done:

1. Did initial tests above with no changes
2. Pulled main power supply and changed all capacitors, fixed a few previous repairs and got the fan working.
3. Checked all cables for continuity
4. As an aside, someone had installed a small audio isolation box on the audio outputs to the PDS128, apparently due to hum.  I also had pulled the AR speakers and found several bad caps (one shorted and one open).  All the caps in the AR speakers were starting to leak - so caught that just in time!

So - a big list of topics for a newbie here.  Hope you folks don't mind.  Any assistance is appreciated!

Mark

------------------------------
Mark Roberts
Farmington NY
------------------------------

Ah yes, memory, a time treasured privilege.  From memory, the early TFT cables had a winged disconnect.  The cable end had two opposing tabs that when pushed away from the cable end would disengage the connection.  It's hard to explain in words.  It would get crunched as the action was taken out or put back in the action cavity.  The small circuit board interface was the answer to that problem.  Maybe there was an edge connector on the TFT end of things.  The cable end would simply slide onto the circuit board edge  .....  under key 88.

Your mods to the p/s sound sensible.  Those old aluminum p/s's were noisy.  The AC hum was the first complaint I ever heard about the product. 

The key solenoids were pulsed and after giving it some thought, perhaps the pedal solenoid was as well.  Strike force would be pulse width and hold force would be pulse amplitude  .....  or something close to that.  Check it with a scope.

Excellent thought to check with a scope.  I don't have schematics of the board driving the solenoid, but bet it's a power mosfet directly driving the solenoid.  I still have not removed the long cover to access the driver CPU board.  Scared of messing with the trapwork...

The connector is a standard IDC ribbon and the one end I can see looks this:

And the hum.  It was not caused by the power supply.  It was caused by the powered AR speakers themselves.  One of the speakers apparently had the failed caps some time back, and the tactical fix was to put a small audio isolation filter at the PDS controller audio output jacks.  I'm only surmising this at this point, but before doing the speaker repairs and without the filter attached, the speakers (one of them anyway) had a noticeable hum.

Again, appreciate the input here.  I now have several contact names/numbers to call PianoDisc and see if they'll listen to me and my questions!  Hopefully will find time to do that this week.

Ah yes, memory, a time treasured privilege.  From memory, the early TFT cables had a winged disconnect.  The cable end had two opposing tabs that when pushed away from the cable end would disengage the connection.  It's hard to explain in words.  It would get crunched as the action was taken out or put back in the action cavity.  The small circuit board interface was the answer to that problem.  Maybe there was an edge connector on the TFT end of things.  The cable end would simply slide onto the circuit board edge  .....  under key 88.

Your mods to the p/s sound sensible.  Those old aluminum p/s's were noisy.  The AC hum was the first complaint I ever heard about the product. 

The key solenoids were pulsed and after giving it some thought, perhaps the pedal solenoid was as well.  Strike force would be pulse width and hold force would be pulse amplitude  .....  or something close to that.  Check it with a scope.

Excellent thought to check with a scope.  I don't have schematics of the board driving the solenoid, but bet it's a power mosfet directly driving the solenoid.  I still have not removed the long cover to access the driver CPU board.  Scared of messing with the trapwork...

The connector is a standard IDC ribbon and the one end I can see looks this:

And the hum.  It was not caused by the power supply.  It was caused by the powered AR speakers themselves.  One of the speakers apparently had the failed caps some time back, and the tactical fix was to put a small audio isolation filter at the PDS controller audio output jacks.  I'm only surmising this at this point, but before doing the speaker repairs and without the filter attached, the speakers (one of them anyway) had a noticeable hum.

Again, appreciate the input here.  I now have several contact names/numbers to call PianoDisc and see if they'll listen to me and my questions!  Hopefully will find time to do that this week.

Ah yes, memory, a time treasured privilege.  From memory, the early TFT cables had a winged disconnect.  The cable end had two opposing tabs that when pushed away from the cable end would disengage the connection.  It's hard to explain in words.  It would get crunched as the action was taken out or put back in the action cavity.  The small circuit board interface was the answer to that problem.  Maybe there was an edge connector on the TFT end of things.  The cable end would simply slide onto the circuit board edge  .....  under key 88.

Your mods to the p/s sound sensible.  Those old aluminum p/s's were noisy.  The AC hum was the first complaint I ever heard about the product. 

The key solenoids were pulsed and after giving it some thought, perhaps the pedal solenoid was as well.  Strike force would be pulse width and hold force would be pulse amplitude  .....  or something close to that.  Check it with a scope.

Excellent thought to check with a scope.  I don't have schematics of the board driving the solenoid, but bet it's a power mosfet directly driving the solenoid.  I still have not removed the long cover to access the driver CPU board.  Scared of messing with the trapwork...

The connector is a standard IDC ribbon and the one end I can see looks this:

And the hum.  It was not caused by the power supply.  It was caused by the powered AR speakers themselves.  One of the speakers apparently had the failed caps some time back, and the tactical fix was to put a small audio isolation filter at the PDS controller audio output jacks.  I'm only surmising this at this point, but before doing the speaker repairs and without the filter attached, the speakers (one of them anyway) had a noticeable hum.

Again, appreciate the input here.  I now have several contact names/numbers to call PianoDisc and see if they'll listen to me and my questions!  Hopefully will find time to do that this week.

Ah yes, memory, a time treasured privilege.  From memory, the early TFT cables had a winged disconnect.  The cable end had two opposing tabs that when pushed away from the cable end would disengage the connection.  It's hard to explain in words.  It would get crunched as the action was taken out or put back in the action cavity.  The small circuit board interface was the answer to that problem.  Maybe there was an edge connector on the TFT end of things.  The cable end would simply slide onto the circuit board edge  .....  under key 88.

Your mods to the p/s sound sensible.  Those old aluminum p/s's were noisy.  The AC hum was the first complaint I ever heard about the product. 

The key solenoids were pulsed and after giving it some thought, perhaps the pedal solenoid was as well.  Strike force would be pulse width and hold force would be pulse amplitude  .....  or something close to that.  Check it with a scope.