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Date Codes on Vintage RCA 5U4Gs?

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musicdre

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Date Codes on Vintage RCA 5U4Gs?
« on: 6 Apr 2023, 05:47 pm »
greetings:  does anyone have a link to, or an explanation of, how to interpret the date codes on old RCA 5U4G rectifiers?  thanks
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FullRangeMan

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Re: Date Codes on Vintage RCA 5U4Gs?
« Reply #1 on: 6 Apr 2023, 06:49 pm »
Its the usual RCA codes.
Brent Jessy site had a article some months ago.
There is other threads on it on the previous pages.
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musicdre

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Re: Date Codes on Vintage RCA 5U4Gs?
« Reply #2 on: 7 Apr 2023, 06:14 pm »
Quote from: FullRangeMan on  6 Apr 2023, 06:49 pm
Its the usual RCA codes.
Brent Jessy site had a article some months ago.
There is other threads on it on the previous pages.

the search function here brought up nothing.   the BJ site contains a great article on euro tube codes.   anyone got a link to RCA codes?  thanks again
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FullRangeMan

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Re: Date Codes on Vintage RCA 5U4Gs?
« Reply #3 on: 7 Apr 2023, 06:42 pm »
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musicdre

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Re: Date Codes on Vintage RCA 5U4Gs?
« Reply #4 on: 7 Apr 2023, 10:22 pm »
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FullRangeMan

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Re: Date Codes on Vintage RCA 5U4Gs?
« Reply #5 on: 7 Apr 2023, 10:36 pm »
Quote from: musicdre on  7 Apr 2023, 10:22 pm
what am i missing?  i did not see anything in these links about date codes on RCA tubes.
And still has to be RCA date codes. LOL
These threads deal on date codes somehow or other.
Do have try the RC30 Manual ?
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FullRangeMan

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Re: Date Codes on Vintage RCA 5U4Gs?
« Reply #6 on: 7 Apr 2023, 10:53 pm »
Sorry to be so incompetent to fulfill your orders.
This google search may meet your demand.
https://docplayer.net/23901469-Date-codes-for-rca-made-tubes.html
1 DATE CODES FOR RCA-MADE TUBES by Ludwell Sibley. There is a sort of fascination with the date codes that are found on tubes. The classic information, on early RCA tubes in particular, is Bro. Patrick Dowd's writeup*. This 13-page brochure goes into (necessarily) exhaustive detail on prewar product. Bits of other "dating data" have surfaced in the radiocollector press and are available in, for example, Tube Lore. Now further - postwar - information has become available 4- via the Dowd-AWA-RCA Harrison archive, and it's time to get it into print. Before going farther, it is appropriate to point out that there were actually three versions of date codes: k Date of manufacture. This was the point of production at fhefactory. B. Date of shipment. This was the date the tube was sent from the maker's warehouse to a set manufacturer (for the original-equipment-manufacturer or OEM market) or a distributor (for the renewal market). C. Date of warranty expiration. This was a date, usually a year after shipment but with some fudging to allow for time in intermediate stock, at which the end user's guarantee would expire. RCA seems to have used only (A) and (B). (C) could have gotten unwieldy, as with, for example, RCA-made tubes branded "Magnavox" and shipped to TV-tuner maker Standard Kollsman Industries for installation in tuners which were then sent to Magnavox' TV factory. (C) seems to have pertained mainly to smaller radio manufacturers. The time from (A) to (B) could vary widely: from only weeks for a high-runner TV tube at the peak of its popularity in new sets, to several years for an obsolete replacement tube. That said, let's go into some detail, as dug out of the Standardizing Notices. We'll include the known postwar codes for some private-brand tubes (Electrohome, GM Delco, Packard Bell, Philco) - not because they draw any big collector interest, but because they illustrate industry practice. These codes were presumably specified by the customers (say, Philco) themselves, and so probably apply to Philco-brand tubes from makers other than RCA. 1. RCA DATE OF MANUFACTURE FOR GLASS RECEMNG TUBES The "etched" octagon giving the tube type carried breaks indicating the year and month of manufacture, as shown in the Dowd brochure. A break in the corner gave year; in the straight part, the month. FOR METAL RECEMNG TUBES The following system apparently went into use in November, The code, stamped into the base ring of the tube, comprised letter for the year and a number (1 through 6) for each two-month interval (Jan.-Feb., etc.) within the year. * "Dating the RCA (Cunningham) Composition-Base Radio Receiving Tubes - From Mid thru 1941," available from Antique Electronic Supply, (602) , as their No

2 Year letters were: 1944 H 1949 J 1953 T 1957 S 1961 N 1966 Z 1970 P 1945 A 1950 C 1954 X 1958 K 1%3 F 1%7 U 1971 Y 1947 N 1951 Z 1955 R 1959 I J 1968 T ' 1972 S 1948 F 1952 U 1956 Y 1960 A 1%5 C 1969 X 1973 K Note the ambiguous 15-year repeat of the letters, except for "P" and "R." The month-number and year-letter sequence was reversed each month. For example, "C6" designates Nov. 1950, whereas "6C" designates Dec FOR SPECIAGPURPOSE TUBES High-value power and cathode-ray tubes carried serial numbers. The serial identification was a year letter plus a fivedigit number. The year letters for were the same as shown above for metal tubes, plus the following (reflecting the later demise of the Lancaster power-tube plant compared to Harrison) H 1977 N 1980 C 1975 V 1978 F 1981 Z 1976 A 1979 J 1982 U The number part of the identification reverted to "1" at start of a new year, at least on types like the 8S8B. On some types like 869B, the serial number substituted for a date-of-manufacture code. (S. N A, p. 3 [ and ]). There were exceptions to this plan. Here are three examples. (A) ~XS00A.s purchased by RCA for resale were serialized, for example, "A8-100." "A" meant Jan., "8" designated 1948, and "100" meant the 100th tube for Jan (B) 826s and 832s had an internal date-of-manufacture code marked on the top mica with India ink, giving the day, week, and year. The day was numbered 1 through 7, the week 01 through 52, and the year was given by a letter as shown above. (S. N , p. 1.) (C) The 927 and similar phototubes received a date of manufacture coded on the stem or rear of the cathode with India ink, giving the month and year: "72" indicates the seventh month of 1942; "81" indicates eighth month of A dot at the end of the code indicates Harrison-made, not Lancaster, product. Unlike usual practice, many phototubes were type-etched, as well as name-branded, at the warehouse. To idcntify nonetched tubes, the base lug or base was branded: A 868 A9 928 B F 1P21 N 1P39 T 5581 AI IP29 B 918 B H P28 U 975 A2 IP37 BI 1640 B J 931A P IP40 V 929 A7 920 B C 917 K IP22 R 5652 A D 919 L 935 S RCA DATE OF SHIPMENT From to The shippingdate code for RG1-brand tubes used a letter for the year, plus a number (1 to 6) for each two-month period within the year, plus "E" for OEM sales. Lack of "E" indicates a tube for distributor sale. The year letters followed the Z-U-T-X sequence seen before: 17

3 19% z 1938 T 1940 R 1942 S 1944 H 1937 U 1939 x 1941 Y 1943 K 1945 V On Government tubes, the "E" was printed separately, typically below the date code. Private-brand tubes generally used a shippingdate code of two or three characters. An initial letter (A through L, including I) gives month, followed by the last digit of the year. Bulk-packed (OEM) tubes also carried an "E"; individual-packed (distributor) ones did not. Thus "55" indicates distributor shipment in Oct. 1945; "L5El indicates OEM shipment in Dec (Note the opportunity for confusion with the nonprivate-brand tubes under the system immediately above: "HSE," say, could mean either of two dates.) From 1-46 to 8-56: For all tubes, the code was the last digit of the year) plus a month indicator comprising the RMNEIh week code, q~lantized to 04 (Jan.), 08 (Feb.), 52 (Dec.), etc. Included is a "sales basis" code: a dash between year and month indicated tubes sold on an adjustment basis; no dash indicates sale on an allowance-inlieu-of-adjustment basis (i. e., renewal vs. OEM business). This scheme covers privatebrand tubes, except where a buyer's special code applies, but not Government tubes. From 9-56: For RCA-brand renewal entertainment receiving types and (effective Feb. 1970) nuvistors, the code was: Jan - Feb Apy WJlln Jul - Oct Nov Dee - KC KG KH KI KJ KKKL Kh4 KN KO Ks KT KU KV KW KX KY KZ LA LE LF LG LH LI w LK LL LM LQ LR LS LT LU LV LW LX LY MC MD ME MF MG MH MI MJ MK MO MP MQ MR MS MT MU MV MW NA NB NC ND NE NF NG NH NI NM AA AB AC ADAE AF AG AH AL AM AN AO AP AQ AR AS AT Ax AY AZ BA BB BC BD BE BF BJ BK BL BM BN BO BP BQ BR BV BW BX BY BZ CA CB CC CD CH, CI CJ CK CL CM CN co CP CT cu cv cw cx CY cz DA DB DF DG DH DI DJ DK DL DM DN DK ED DS EE DT EF DU EG DV EH DW E1 DX EJ DY EK DZ EL EP EQ ER ES ET EU EV EW EX FB FC FD FE? FF FG FH FI FJ FN FO FP FQ FR FS Fr FUFV 1956 and 1957 are unconfirmed; the notice sheet is missing. 1956' 1957' &* K D K E K F KP KQ KR LB LC LD LN LO LP LZ MA MB ML MM MN MX MY MZ NJ NK NL A I A J A K AU AV AW BG BH BI BS Br BU CE CF CG CQ CR CS DC DD DE DO DP DQ EA EB EC EM EN EO EY EZ FA FK FL F'M w EX FY For other markets (military, professional - all except entertainment receiving tubes sold for renewal/resale), the date of shipment is in the EIA format with two-digit year and the week as shown as above. There were some twists: (A) A plain format ("5652") indicates the tube was sold on an adjustment (rcnewal) basis, while an added dash ('56-52") means an allowance (OEM) basis. 18

4 (B) Purchased types generally carry a following dot ("5652.", "56-52.", or "KC."). (C) Types with a preceding dot ("0 5652," ".56-52," or "0 KC") had been adjusted and returned to stock. (D) Tubes for export were datecoded with an " X ("56x52"). (E) The RMA-assigned "274" code identimng RCA as the source was added on tubes lacking the RCA brand, i. e., private-brand. (The "274" code officially indicated "sponsor-of-sale," not necessarily the actual maker, as on types occasionally bought by RCA for private-brand resale.) (F) Military tubes included a plant-location code. DATE (AND DESTINATION) CODES FOR GM DELCO TUBES These originally used the short version of the EIA date code: the last digit of the year, plus a week code. The latter is quantized to the quarter of the year, i. e., 13, 26, 39, or 52. See the example below. The tubes carried the RCA "source code" (274). In addition, because Delco OEM tubes went to any of several radio manufacturers, the destination (original purchaser) is designated by a symbol after the date code: + Colonial 0 RCAVictor 0 Crosley Hallicrafters Delco Radio Corp. As an example, "613 0' stamped under the "274" designates a firstquarter 1946 tube for Crosley. Later the date code became as follows: Jan - Feb - Mar Ap' May Jun 1957 RR RA RL RM RO RT 1958 AR AA ALAM A0 AT 1959 LR LA LL LM LO LT 1960 MR MA ML MM MO MT 1961 TR TA TLTM TO?T 1%2 SR SA SL SM so ST 1963 UR UA UL UM uo UT 1964 DR DA DL DM DO DT 1965 ER EA EL EM EO ET 19G6 NR NA NL NM NO NT 1967 RR RA RL RM RO RT 1968 AR AA ALAM AO AT DATE CODES FOR PIIILCO TUBE Jul RS As Ls MS Ts ss us DS ES NS RS AS A% RU AU LU MU Tu SU UU DU EU NU RU AU SeP RD AD LD MD TD SD UD DD ED ND RD AD - Oct - Nov RF AEAN AF LE LN LF ME MN MF TETN TF SE SN SF UE UN UF DE DN DF EE EN EF NE NN NF RE RN RF AE AN AF LE LN The code is the full version of the EM code: the last two digits of the year plus the week code. The week code is restricted to even numbers only, thus indicating the first or last half of the relevant month. The year and week are separated by a dash, indicating the tube was sold on an "allowance" (OEM) basis. The date is predated 3 mos. in advance ol actual shipment, f. 1 week. This scheme applied as of June, 1949, and apparently was used to at least It included tubes branded for Philco subsidiaries like the Sierra Electronic Corporation. Writer Nan Douglas found an earlier version of this code using the letters 0, P, U, 19

5 and S, starting in RCA files confirm it was in use as of The code was: Shipment Code Code from RCA Letter Period 11-1 to to to 4-30 P 4-1 to to 7-31 U 7-1 to to S 10-1 to DATE CODE FOR PACKARD BELL TUBES The following code covered Packard Bell (later, Teledyne Packard Bell) tubes: Janall 4pyrJunJltl &sejoctoctdec 1963 EBA ELA EAA ECA EKA EHA EOAERA ESA BEA BBA BLA 1964 EBC ELC EAC ECC EKC EHC EOC ERC ESC BEC BBC BLC 1965 EBK ELK EAK ECK EKK EHK EOK ERK ESK BEK BBK BLK I966 EBH ELH EAH ECH EKH EHH EOH ERH ESH BEH BBH BLH 1967 EBO EL0 EA0 ECO EKO EHO EO0 ERO ESO BE0 BBO BLO 1968 EBR ELR EAR ERC EKR EHR EOR ERR ESR BER BBR BLR 1969 EBS ELS EAS ECS EKS EHS EOS ERS ESS BES BBS BLS 1970 EBE ELE EAE ECE EKE EHE EOE ERE ESE BEE BBE BLE 1971 EBB ELB EAB ECB EKB EHB EOB ERB ESB BEB BBB BLB 1972 EBL ELL EAL ECL EKL EHL EOL ERL ESL BEL BBL BLL 1973 EBA ELA EAA ECA EKA EHA EOA ERA ESA BEA BBA BLA 1974 EBC ELC EAC ECC EKC EHC EOC EKC ESC BEC BBC BLC DATE CODE FOR ELECTROIIOME (CANADIAN) TUBES These carried a letter (A thru L) for the month, plus the last digit of the year. 3. SPECIAL CODES ON CRTs Many early CRTs like the 7JP4 carried a special three-letter code for quality-assurance use (S. N ). The first letter indicated the work day of the month; letters ran A through Z, I and Q included. The second letter (A, R, etc.) designated the sealing machine. The third letter (A, B, C) indicated first, second, or third shift. Monoscope tubes like the 1699 that used a custom-ordeted test-pattern design were to be stamped, above the type number, with an indication of the customer, for example, KSTP-TV.. Color kinescopes carried a year letter on the brand stamp. The letter was the same as that seen earlier on metal and power tubes: Pre B 1968 T 1971 Y 1974 H 1964 C 1966 z 1969 X 1972 S 1975 V 1964 J 1967 U 1970 P 1973 K 1976 A RCA marked kinescopes purchased for resale as follows: 274A Lansdale 274H Eitel-McCullough* 274W Westinghouse 2748 American Television 274K GE 274X Thomas 274C National Video 274P Hytron 274Y Tung-Sol 2740 Sylvania 274s DuMont 274E Arcturus Electronics 274U Rauland Corp. * Eifcl-McCullough arid CRTs? Yes, Eimac made some IOBP4s and similar types for RCA ca at its Salt Lake City plant. 20
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