Crown production date codes and likely OEM models:
Most recent update: September 2015 — please note that this is an ongoing "personal project" of mine, ever changing as I collect new data — please don't take anything here as written in stone:
As far as I've been able to tell, most of the best-known Crowns made circa 1959-1960 made use of production date numbers or final inspection date numbers rather than serial numbers. (Below I'll use the term, "production date", but "final inspection date" may turn out to be a more accurate term — right now I don't know.)
One of several possible early production date formats that Crown (Asahi Musen) used is the one found in my own TR-666 example, where the numbers stamped on the cabinet's back inside label read: 05 26 59, a mm/dd/yy scheme that includes spacing between the pairs of digits. Currently this is the only example I've seen of this numbering scheme, but it seems likely that it may have been used for some of the other Crown models that were produced before Asahi Musen began using its most common production date scheme. Asahi Musen also apparently used other numbering schemes as well on various early models I've come across, though how any of those schemes worked is still a complete mystery to me.
The production date numbering scheme found on the most popular Crowns circa 1959-1960 follows a mostly straightforward dd/mm/yy format. The fifteen examples below come from pages on this web site, a page on Alan Kastner’s web site, a page on James Butters’s web site, several Radio Museum page posts, and several listings on eBay — there are many photos of Crown radios featured on the Web and in books, but these are the only ones I've found that show the cabinet's back inside label, where the numbers are found:
My TR-333: 170759
AK’s TR-333: 250359
eBay TR-400: 0255 59
My TR-555: 320360
eBay TR-666: 400259
RM TR-666: 250459
My TR-670: 301159
JB’s red TR-670: 101159
JB’s black TR-670: 120160
AK’s TR-777: 280759
My TR-7S: 201159
RM TR-7S: 201159
My turq TR-800: 021259
RM TR-800: 100959
My Lafayette FS-200): 240759 (made by Crown/Asahi Musen)
For twelve of these fifteen examples, none of the first pair of digits exceeds 31, none of the second pair of digits exceeds 12, and all of the third digit pairs are either 59 or 60.
Only three of the examples above fall outside this simple dd/mm/yy format — one is my TR-555 with its 320360 number stamp exceeding the 31 maximum limit for a calendar month by one, though its second and third digit-pairs do retain their mm/yy format. (This slight-overreach shows up again when looking at the four 9-transistor OEM (Original Equipment Manufacturer) models listed below that I believe were made by Asahi Musen.) The other two examples that don't fit the scheme are the eBay TR-400 (0255 59) and the eBay TR-666 (400259). The TR-400's number stamp might be a serial number+year code.
The best way to confirm that these numbers are production date codes and not serial numbers would be to find two different examples that share the same number, and that’s shown among the codes above: the TR-7S example found here on this site and a TR-7S found on the RadioMuseum site are two separate units sharing the same number stamp of 201159. These two units obviously don't share the same serial number — what they most likely do share is the same production date of November 20, 1959.
This date numbering scheme continues being almost straightforward when adding into the mix some OEM models long suspected of having been made by Crown, those 9-transistor shirt pocket sets such as the Lafayette FS-91, Harpers GK-900, Kowa KT-91, and the Viscount/Chic KT-91 — all four models share the same cabinet and chassis, and all four very obviously were made by the same manufacturer — but the question always has been, who was that manufacturer? I've always thought it was Crown (Asahi Musen), and for me the number stamps below confirm my suspicions — but with one small catch involved, something already encountered in the Crown group above.
Four of the nine units' number codes listed below fit Crown's seemingly simple and straightforward c.1959-1960 dd/mm/yy date numbering scheme, now extending the end-digits to 61: my Lafayette FS-91, James Butters's FS-91, an FS-91 listed on eBay, and my Harpers GK-900 — my FS-91's number stamp is 260261 (Feb 26, 1961), James Butters's FS-91 number stamp is 091260 (Dec 9, 1960), the eBay FS-91's number stamp is 250161 (January 25, 1961) and my GK-900's number stamp is 140560 (May 14, 1960).
On the other hand, the Harpers GK-900 example shown on James Butters's page has a number stamp of 330560 that doesn't quite fit the scheme, and neither do the examples I have of the Kowa KT-91 (320460) and the Viscount/Chic KT-91 (320760), nor do the Kowa KT-91 example found on a RadioMuseum page (320460) and a Kowa KT-91 example owned by Alan Kastner (320560):
My Lafayette FS-91: 260261
JB's Lafayette FS-91: 091260
eBay Lafayette FS-91: 250161
My Harpers GK-900: 140560
JB's Harpers GK-900: 330560
My Kowa KT-91: 320460
RM Kowa KT-91: 320460
AK's Kowa KT-91: 320560
My Viscount KT-91: 320760
The obvious problem with the list above is that five of these nine OEM units have codes whose first pair of digits exceed 31: four have 32 and one has 33, all exceeding the calendar month scheme of 31 days maximum. And then there's my Crown TR-555 example listed above with its 320360 number stamp.
For me, this doesn't disqualify those numbers as being date codes — note in the list above that my Kowa KT-91 example and a Kowa KT-91 example found on a RadioMuseum page share the same number stamp: 320460. These can't be serial numbers if they share the same stamp number — they're almost certainly date codes, though exactly why these and several other units here would have codes beginning above 31 is really beyond me at the moment. But keep in mind that all of the renegade digit-pairs found so far have barely crept past the 31 limit for whatever reasons and that the rest of the digit-pairs in all four examples in question here remain consistent to a mm/yy date code scheme.
So, of the 24 examples listed so far — both Crown and suspected OEM units — the seven examples with number stamps exceeding the 31 limit on the first digit pair include five with 32, one with 33 (JB's Harpers GK-900), and one with 40 (eBay TR-666) — obviously more examples are needed here to flesh out some sort of pattern.
(One thing to note here, though it very possibly may be nothing more than coincidence, is that all three Kowa KT-91 examples and the Viscount KT-91 example have number stamps that begin with 32, even while only two of these four units share the same remaining digits in their number stamps.)
Concerning the Kowa KT-91, I suspect that in this instance, strange as this may sound, Kowa was only a distributor (Kowa American, Inc., New York) of the KT-91 and not in any way its manufacturer, just as Harpers, Viscount and Lafayette were distributors for the other three assumed Crown OEM models here — currently this is the only way that I can make sense of Kowa's involvement in these OEM models without Kowa having been a manufacturer of some of these sets and another company the OEM of the others. All four models share the same cabinet and chassis, and all four very obviously were made by the same manufacturer, so here it's a case of "all or nothing" — Crown couldn't have made some of these models and Kowa the others. The only alternative I can see is that Kowa was the manufacturer for all four of these sets. But these don't look like any other Kowa radios I've ever seen — but they sure do look like Crowns!
Almost no* other examples I've looked at from any other Japanese manufacturer of the time have number stamps even in the least bit similar to these, and most in fact clearly designate their number stamps as being serial numbers, something universally missing from all the 1959-61 Crown/Asahi Musen models' examples noted on this page, both for Crown's own models and for what I believe are its OEM models. (One prominent collector, playing devil's advocate, has suggested, "...those date stamps could simply be something Shriro Trading requested on models they ordered from a number of OEM makers." But when I looked at more than a dozen Linmark examples (also distributed by Shriro), not one had any kind of stamp on its inside label — not a single serial number, and certainly not any date code.)
(*The distributor Harlie Transistor Products, Inc., New York, used a number code scheme on several of its models sharing the same cabinet (TR-10, TR-659) that is nearly identical to Asahi Musen's code, though this may well have been nothing more than coincidence. I have no idea what company made these Harlies, though Shirasuna Denki (Silver) has been offered on Radio Museum pages as the mfr of the Stantex TR-4 model that shares the same cabinet as these Harlie models.)
While I think it seems reasonable to say that Asahi Musen used production date codes on many of its 1959/60 Crown models and on at least one of its OEM models (the Lafayette FS-200), this still leaves at least two questions unanswered:
— why does the otherwise straightforward dd/mm/yy date code sometimes creep above 31 in the first digit pair?
— was Crown the OEM for the four nine-transistor models (Lafayette FS-91, Harpers GK-900, Kowa KT-91, Viscount KT-91) listed above?
Without solid documentation, much of this remains conjecture for the moment — but I do hope to receive historical documentation not too long from now that could clear up some of these questions!
Two big outliers:
Two Crown radio models I haven't mentioned so far are the two 9-transistor "monster Crowns" — the TR-911 and the TR-999. That's because I don't know what to do with them in terms of the production date scheme offered above. Neither of my examples fits the scheme, not even close. My TR-911 is the only Crown radio of its c.1959 vintage I've seen that has what appears to be a serial number (243124) and not a production date code. But then a Crown TR-911 recently listed on eBay has what appears to be a date stamp: 260262 (February 26, 1962), adding a bit to my creeping suspicions that the 911 and 999 models may have been produced quite a bit later than their currently accepted "circa 1959" date. And my TR-999's stamp (£263) doesn't appear to be either a serial number or a production date code. No ideas here. Other examples of both models' number stamps would be helpful, but the only web pages I've found so far that show these models don't show their inside back covers, and that's where the numbers are.
Other Crown OEM models:
One OEM radio that without question was made by Crown/Asahi Musen was the 1959 Lafayette FS-200 — this radio shares exactly the same cabinet and chassis as the Crown TR-666, and it also makes use of Asahi Musen's production date scheme for this particular unit, with a number stamp of 240759 (July 24, 1959). (But note that an FS-200 example found on Pete's Radioworld has a number stamp of 710056 — here, none of the three digit pairs correspond to a date numbering scheme!)
Another radio that I've long suspected as having been made by Crown is the 6-transistor Harpers GK-631 — who else but Asahi Musen could have made a radio with these particular design elements? The number stamp on my GK-631 example adds credence to this notion: 150560 (May 15, 1960). Again, only Asahi Musen appears to have made use of this numbering scheme. And I've been told by a prominent collector and historian that, "At least a couple of Harpers models came from Asahi Musen/Crown, (including the earlier TR-3A)."
Going outside this c.1959-61 group of Crowns in search of production date schemes becomes even more frustrating and inconclusive — at least it does for me at the moment:
The earliest Crowns (1957 & ’58) may have had production date numbering schemes, whether full or partial (year only) — some of these earlier models may have had just plain serial numbers and others may have incorporated year codes into their serial numbers. A RadioMuseum page for the Crown TR-86 shows the number 52158 with possibly an additional digit missing at its beginning and/or end. And a RadioMuseum page for the early Crown TR-820 shows the number 302957 — maybe both of these are date codes, maybe neither one is. Alan Kastner shared with me photos of two of his early Crowns he had at hand: SA380758 for a TR-610, and 041 658 for a TR-830. And a recent eBay listing for a TR-610 has a number code of 104459. These five sets of numbers don't appear to share much in common with one another, other than that each one ends in 57, 58 or 59:
RM TR-86: (_?)52158(_?)
RM TR-820: 302957
AK's TR-610: SA380758
eBay TR-610: 104459
AK's TR-830: 041 658
I've only recently begun looking into all this — as I continue to collect more number stamps off of eBay listings, I'll be able to add more examples to the number lists above, and maybe I'll even be able to figure out a thing or two. I'd really like to see more examples of number stamps from any Crown radio models that you own, including the suspected OEM models — please email me with the numbers you have or any other info you can share!