The Date of your Wurlitzer Electric Piano

See Steve’s unprecedented online list of every model of Wurlitzer Electronic Piano ever produced, 1954-1983.

Steve repairs Wurlitzer Electric Pianos in the greater New York City area. He makes house calls, for an additional fee.

• You can date-confirm your own Wurli! Please do and send me the data (photos if possible for verification), which will improve this resource.
• I have a goal of creating a concordance between serial numbers and years and months that instruments were produced. I am getting there. This information, once it is decently un-crude, will allow people to know, within a reasonable range, the year of their instrument simply by knowing the serial number.
• First of all, find your serial badge and take a good photo of it.  And note the color of your instrument. In a 200 series instrument or later, the badge will usually be under the keyboard, on the left side, near the 1/4″ jack(s). In earlier instruments, especially portables, this may be on the back or side panel. We want to know the model number and the specific serial number, including any inked or stamped letters like “L” or “P”. Look as well for any light stamps next to the model number, like an “A” next to an inked “140” or “145.”

Model 200 Serial # 52561. No “L”. Please note that this number is NOT a date stamp. Every instrument has a distinct number. They are not completely chronological, but ranges of numbers are allotted to runs of instruments in a model or series. There is more information about this elsewhere on the site.

A 140A serial badge on the back of the instrument. Notice that the “A” in the “model number” box is just lightly embossed next to the inked “140.” Sometimes it’s almost invisible. They were using up 140 plates! (image yanked off an auction site.)

• The More Date Stamps, the Better. Since each date stamp is only for a given part, and parts were stockpiled, we want to know ALL dates in your keyboard (AND its serial number); the latest date found is the most useful date, and will generally be within a couple months of the assembly of the instrument–but please send all of them. Please check:
  • action rail
  • speakers (not on the cone. On the metal back),
  • keys (including handwritten date on lowest key, if found)
  • transformer,
  • plus keybed, capacitors/tubes, the amp itself (which is usually stamped on the top, left of heat sink, in an uncoded manner, especially on 1971-1974 pre-A 200 series), damper assembly rails (seldom, except on 111’s-112’s, where it is the most commonly found date).
  • Handwritten month-day on the lowest key (A-1) (1968-1972, non-L instruments) is especially useful, if you see it. Details below.
  • Triangulating those first 3 items is the most useful way to get an accurate date.  Far more accurate than just getting one date.

• Without a serial badge, sending the dates you find in the instrument is usually not very interesting.  There are exceptions.  But the purpose of this project is to create a concordance of serial numbers to dates.
• The serial number does not contain a date.  It is a unique sequence number.  Sometimes people will see a serial number that seems to contain a year; for example, 122974L.  That “74” does not mean “1974.”  It just means it’s the instrument produced just after 122973L and just before 122975L, all within the same duration.  (In fact, those instrument would have been assembled at the cusp of 1977-8.)
• Please do not pre-interpret and clean up/withhold the raw data. It’s more useful to me to have the encoded numbering than to have you merely report “I crunched all the numbers and it’s from November 3, 1974,” without sending the actual numbers.  I’m tracking the individual data points; and I would like to have all of them to check the work.  You are welcome to send your interpretations as long as you don’t withhold how you arrived there.

The dates in your instrument

I had a Eureka moment a few years ago, and figured out that, by late 1962, all Wurlies used a consistent, encrypted date-stamping system for production of the keys, the action rails (where the damper arms and hammers are mounted), and sometimes the keybeds. The keys and main action rails will be stamped YMMDDXXX (colors my own); sometimes a digit at either end will be smudged, faint, or covered. (Those last “X” digits are a sequence number to differentiate each part.) The year-digit (Y) doesn’t include the decade; so, August 31 1976 keys will be stamped “60831XXX,” with the “6” meaning “1976.” You need to know the span of years in which your instrument was produced to interpolate the first 3 digits of the year (in other words, “196-“, “197-” or “198-“).

After lifting the lid, the action rail stamp is the easiest of the crucial date stamps to find — but we want to get additional stamps if we can, as this may not be the latest date. This stamp is behind the treblemost “chopped dampers” on most instruments from 1963 on. (Occasionally it is at the bass end in the first year of the stamps.) This is a 200A. 200A series instruments (also including 210’s, 270’s, 200B’s and all other models starting with “2 and ending with “A”) were made from 1974 to 1983. The date format is YMMDDXXX. So the first “2” here indicates a year of 1982. “0219” means “February 19th.”

To read the key dates on any 200 series instrument or beyond, you need to remove the amp rail. This is from a Model 200. The “pre-A” 200 series instruments, including 203, 203W, 206, 207, 214 (all without “A” in the model number) as well 106, were produced from 1968 to 1974. The date format is YMMDDXXX. So the first “0” here is short for “1970.” Then, “0828” means “August 28.” “587” is a production sequence number. Notice that “CM” handwritten date!! That’s the best data you can find, if your instrument has it. That will almost always be the latest production date on the instrument: In this example, Nov. 4, 1970. (This “CM” or RT” number appears only on 200 series instruments produced from 1968 to 1972 with no “L” in the serial number.) If this was a 200A instrument, that first “0” would indicate 1980, instead of 1970.

The keys of this model 270 read 60831700. Remember, the code is YMMDDXXX. This instrument is from the 200A era, which ran from 1974 to 1983. So we know that the “6” means “1976”. “0831” means “August 31”. “700” is a sequence number to give each set of keys a distinct number.

• 200 series instruments (pre-“A”), from 1968 through 1972, with no “L” after the serial number, will almost always have a handwritten month and day on the leftmost key, under the amp rail. They will be accompanied by an initial: usually “CM”, but sometimes “RT”, “RP”, or a few other initials. Without fail, this will be the latest date in the instrument. It will not include the year, but that data can be found in the other stamps. See example above. (Note–as this number is under the amp rail, it will take significant dis-assembly to reach it. I don’t recommend this unless you have other reasons to take your Wurlitzer apart, and you know what you are doing.). Instruments with an “L” will not have this date: That letter means they were assembled in Logan, Utah, after operations moved there in 1972.  At that point production tripled for several years. Either CM and RT didn’t make the move, or they were taken off instrument-tagging duty.
• The other most important date, especially if there is no handwritten CM/RT date…. is on the back of the speakers! I find that sometimes –rather often, in fact– this is the latest date in the instrument. Maybe about 1/3 of the time. In some instruments, like the non-hybrid 200A portables, this is a pretty easy number to access: Just lift the lid! If the speakers are attached to the amp rail, you may need to sneak a camera at a strange angle, or wait until the amp rail is removed.  Note:  You are looking for the numbers on the flat metal back of the speakers, not on the cone or rim.  There will usually be part numbers and lot numbers as well.

Bass speaker (part 11-0750) in an early 200. 137 is the EIA code meaning the speaker was manufactured by CTS (Chicago Telephone Supply).

Treble speaker (part 11-0751) in the same instrument. “6912” in the bass speaker and “6913” in the treble speaker mean that these were manufactured in the 12th and 13th weeks of 1969.

A very early square-backed 200A “lid” speaker. Again, 137 is CTS, and 7519 is the 19th week of 1975. 204466 is the part number.

Some later round-backed 200A lid speakers were part number 204586.  “91” is reportedly the EIA code of Oaktron Industries, Inc, and “7746” is the 46th week of 1977.  (Other round-backed 200A speakers were part 204887, made by Pyle, EIA code 1098)

• Please note the numbers on the transformer.  The top row is a part number.  The next line will usually start with “831” (Better Coil & Transformer) or “606” (Woodward-Schumacher), followed by a year and week code. (YYWW or YWW).  It’s rarely the latest number, but it’s still good data.
• In instruments from 1963 through 1969, the keybeds (under the keys) will often have 5-digit codes consisting of YMMDD. There will be a different date at the top and bottom ends of the keyboard. They are good dates to get, if you can. These will almost always be earlier dates than on the keys, and it appears the left-side date is always earlier than the right-side date. (In 1962-3 instruments, you may just see a 2-digit week of the year:  “33”, for example.)
  

• Early 1970’s instruments will often have a straightforward number on the keybed, under the keys. In the German produced model 201 and 300 instruments, this will be one of the few easy-to-find dates. In US-produced models, this will rarely if ever be the latest date in an instrument.
• Once in a while we will see a dyslexic number (probably from manually setting a number while looking at the stamp head-on), or the work of someone who didn’t quite get the concept. So, for example, some of the last 1983 Wurlitzers have “40” in the month digits, when all other data would indicate they should have read “04” (April). Some red-inked keys of very early 720’s seem to have two digits for the year: “62” instead of just “2”…. followed by only one digit for the month: “9”. This got cleared up pretty quickly.  (5-digit keybed example higher on page.)
• The very earliest 140’s (and presumably the 145’s and 720’s) used different, 6-digit stamp codes. Apparently: YWWxxx. (Year, and week of the year.) 2-digit stamps on keybeds may indicate the week of a given year, as well. (So far, data seems to be consistent with other clues.)
• This site can help decode dates found on transformers, speakers and volume/vibrato potentiometers. This used to be the preferred method of dating Wurlitzers, but other than the speakers, these will generally predate the stamps found on the wood by a few months to even years: http://www.triodeel.com/eiacode.htm 
• This site counts weeks of years. Here’s the link for 1962: http://www.epochconverter.com/weeks/1962
• Since no model of Wurlitzer was produced for more than 10 years, you can use this chart to get a general sense of the period of your model, then use the stamp on your keys and keybed to pinpoint it. The key stamp date is NOT the assembly date, but probably the date the keys were cut. (Theorized because: Sometimes a single keybed is made from two pieces of wood, each with a different stamp at the transition point). Still, usually, it is close. (Sometimes the upper and lower ends of a keyboard have different date stamps, if two pieces of wood were used.) Triangulating using as many date stamps as possible (from keybed/balance rail, keys, transformer, speakers, volume knobs, and amp) will give you a pretty close idea, and usually (not always) the stamps on the wood will be among the latest dates. In one known case, the keys are from 1971 but the keybed is stamped 1973; in another, a very early 200 has a later transformer stamp than the keystamp date, by months; but usually the keys are stamped within a week earlier or later than the keybed. (If you do send me data, PLEASE include the serial number and model number, including any letters like “A” or “B” or “P,” from the instrument’s badge, and the precise literal stamp numbering, and their locations. The letters are crucial: a 140B is a different animal than a 140. Photos, pref multiple, are much better, too.)
• The earliest models, from 1954-1956 (110, 111, 112, perhaps 112A) usually have an un-cryptic date stamped into the wood near the damper mechanism.
• The rare 110 tends to have a month and year date stamp on the SIDE of its lowest hey. A stamp that reads “1254” probably means “December 1954. (Please check the keys of your 111 or 112 to see if a similar stamp exists!)

The models from 1957 to 1961 (the 120 and 700) are seemingly the hardest to date, though we Wurly geeks are working hard to figure it out.

• Your best bet is to note the serial numbers of instrument and amp, and take coded numbers off the amp tubes, transformer and speaker. Sometimes a handwritten inspection date can be found on the back of the reedbar, on masking tape; however, that tape is impossible to read without removing the reedbar. It shouldn’t be done unless necessary for other maintenance.
• Our keyboard-collecting comrade in Seattle, Matt Subtle/Sotl, recently discovered that one of the topmost two keys of a 120 or 700 usually has a date stamp on its underside! (Please check for such a date on 112A’s too–they were also Pratt-Read actions.) 
• On another 120 from early 1957, I found a date stamped into key A#-50, with another slightly later date scribbled on the bottom. This date matched that found on the speaker. However, this may not be the latest date on your instrument –even by a factor of up to 6 months–so please check the other dates mentioned just above, too.