Wurlitzer 200A sound is all distorted

[dbjacobson]

I turned on my awesome 200A and now all the sound is super distorted - I have ruled out the speakers themselves as I replaced the internal ones with brand new ones last year and the distorted sound also comes out through the AUX out and the headphone jack. Any idea what has caused this sudden problem and how to fix it? I am no longer "Riding on the Storm!"
Thanks in advance,
Doug

Wurlitzer 200A sound is all distorted

[soundguruman]

I turned on my awesome 200A and now all the sound is super distorted - I have ruled out the speakers themselves as I replaced the internal ones with brand new ones last year and the distorted sound also comes out through the AUX out and the headphone jack. Any idea what has caused this sudden problem and how to fix it? I am no longer "Riding on the Storm!"
Thanks in advance,
Doug

Wurlitzer 200A sound is all distorted

There are two things that cause this problem,
1. there is crud in tine bar, between the bar and the tines...
English translation: The wurlz 200 does not have strings, it has tines. There is one tine for each note. Each tine is tuned to a musical pitch.
How to tune the tines?: That grasshopper is a different story.
When you press each piano key, it actuates a hammer, just like a real piano. The hammer strikes the tine, and the tine rings like a bell.
The tines are mounted on a bar charged with high voltage. There is a magnetic pickup for each tine.
Now that you are filled in:
A. if crud, such as dirt or debris gets into the tine bar, between the tines and the bar, it will cause horrendous distortion. This is because the crud is conductive enough to cause small arcing between the tines and the high voltage bar.
This causes a FUZZ sound, like a distortion pedal, when notes are played.
It MAY be one piece of crud, stuck between one tine and the tine bar, OR it can be a whole bunch of dust and dirt, that has built up inside the piano over many years.
Solution: The piano must be completely vacuumed out, very thoroughly. Use a brush to loosen dirt or dust between the tines and the tine bar, while sucking up the dirt with a shop vac hose.
Clean every spec of dust or dirt, debris, out of the piano interior.
After brushing vacuuming, take a business card, and sweep between each tine and the tine bar. There will be two spaces between each tine and the tine bar. Use the business card to clean each gap of EVERY tine. This is to insure that there is no debris in the gaps between the tines and the tine bar.
After you are certain that every gap is perfectly clean, and the piano has been completely vacuumed out, test again.
Many times this will cure the distortion problem.
I completely disassemble the entire piano, including the keys, and clean the entire case out. As you can see, any dirt inside can get caught between the gaps, and cause major problems.
Sometimes the gap actually burns from arcing, but that can also be repaired.

2. Each tine has a pickup. If the pickup is touching the tine, it will cause major distortion. The distance between the tine and the pickup is adjustable, and if the pickup has come lose, it may be touching the tine. Check the clearances between the pickups and the tines, and check for lose pickup hold down screws.

Almost all distortion in the wurlz 200 is caused by dirt, arching in the tine bar. OR a pickup that is touching a tine.
Careful cleaning between the tines and the bar, make sure the gap is cleaned, will fix it almost every time.

OCD: After complete dis-assembly and cleaning, hold the tine bar up to a light.
Visually inspect to see that each tine has a clear gap between the tine and the tine bar. Any closed gaps will need to be fixed.
Make sure you can see light through each gap. If the gap is closed it will block the light. Sometimes a business card can be used to clear the gap.

Sometimes you can use a piece of masking tape, folded into a flat wedge, sticky side out, to clean between the gaps. OR double sided tape stuck to a business card, will help "grab" the debris between the gaps. This method works quite well. Clean ALL the gaps, and do it over and over until the tape comes out of the gap clean. (use lots of clean tape) As soon as the tape grabs dirt from the gap, don't put it back in again. Use a clean piece to repeat the gap cleaning until the tape comes out clean.

Tines out of alignment: Each tine can be loosened, it has a 1/4 inch hex head screw. Loosen the tine and adjust the gap, so that the gap is even on both sides of the tine. Make sure the tine is free and not touching the tine bar when it vibrates.

Tuning: you will need a soldering iron, a strobotuner, solder wick, flat file, a vacuum cleaner, ha ha that's a fun one.
Yes, you tune this piano with a soldering iron. And lots of skill.

Anyhow no matter what you do, disconnect the power first, it is possible for the power supply to hold a charge after it is un plugged.
The tine bar is ENERGIZED! with high voltage. Watch out and take precautions accordingly.

[Steve L]

Depending on the year the piano was made, there are two small fuses on the printed circuit board that is under the cover, in the middle of the keyboard.
One of these is likely blown. Sometimes they blow without any apparent cause, sometimes there is a problem such as a shorted output transistor.
Most of the time, they just blow and replacing them gets the piano working again. Try looking at these first.

Steve

[Rhodesplyr]

I agree with the fuse suggestion. I'd add that these fuses are no longer a standard size and that standard practice is to replace both of them with "in-line" fuse holders that are held off the board by wires. This makes it much easier to replace the fuses, should one blow again. This is especially helpful if it turns out that there is a bad transistor. All 200A pianos I've worked on have two fuses attached to the PCB with wound-wire holders. You can't replace these without desoldering them.

It's good to check for dirt in the pickups, but I think that the statement that almost all distortion in Wurlitzer 200A pianos is the result of trash in the pickups is a bit of an overstatement. The electronics in Wurlies are notoriously flaky, especially as they're getting older.

As for "Riders On The Storm," it's hard to tell from the recording, but Ray Manzarek has confirmed that he played it on a Rhodes, not a Wurlie :-)

[soundguruman]

"No apparent cause" is crud, particularly metal, caught in the tine bar. And I will tell you why...
The piano is tuned with solder, and a file. This means that the fine tuning leaves very small metal particles inside the piano.
The particles get caught between the tine bar and the tines, the bar is energized with high voltage. The tines are grounded. This metal inside the gap causes a short circuit on the power supply and the fuse blows.
Sometimes it even burns the tine...and arc welds itself to the tine bar.
However usually, a small piece of metal is just enough to cause arcing, and not a dead short. This is the distortion you hear.

I have worked on AARPs, Moogs, Mellatrons, Farfisias, Fender Rhodes, Hammond, Puttney, Yamaha, Roland keyboards, but you guys are too young to remember this one...it's older than me.

[Rhodesplyr]

I have worked on AARPs, Moogs, Mellatrons, Farfisias, Fender Rhodes, Hammond, Puttney, Yamaha, Roland keyboards, but you guys are too young to remember this one...it's older than me.

Excuse me, but I'm older than the Wurlitzer 200A and the 200.

I do work on these same keyboards--all the time. The last two 200As I've worked on had blown fuses on the PCB. (And, yes, I've replaced reeds on Wurlies and tuned them.) Your explanation of metal particles in the pickup causing a power supply short is simply wrong. Why? There's at least 2Meg of resistance between the high voltage supply diode and the pickup. Not enough current can flow, even in a total short, to blow the main power supply fuse. This is not to say that conductive particles in the pickup can't cause trouble; they certainly can, but it's not always the cause.

The fuses Steve and I are talking about are not the main power supply fuses. They are in series with the output transistors on the power amplifier board of the 200A. They will blow in the event of a shorted output transistor, and, sometimes, they will blow for no apparent reason, other than, perhaps, age and vibration.

[soundguruman]

Excuse me, but I'm older than the Wurlitzer 200A and the 200.

I do work on these same keyboards--all the time. The last two 200As I've worked on had blown fuses on the PCB. (And, yes, I've replaced reeds on Wurlies and tuned them.) Your explanation of metal particles in the pickup causing a power supply short is simply wrong. Why? There's at least 2Meg of resistance between the high voltage supply diode and the pickup. Not enough current can flow, even in a total short, to blow the main power supply fuse. This is not to say that conductive particles in the pickup can't cause trouble; they certainly can, but it's not always the cause.

The fuses Steve and I are talking about are not the main power supply fuses. They are in series with the output transistors on the power amplifier board of the 200A. They will blow in the event of a shorted output transistor, and, sometimes, they will blow for no apparent reason, other than, perhaps, age and vibration.

If the power transistor was blown, there would be a 120 cycle buzz in the speakers, and the piano would not be working at all---It's dirt.
FYI the tines can arc weld to the tine bar, this is an appreciable amount of current, enough to blow the fuse.