Filter Capacitor MFG Date Code Decoder

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Filter Capacitor MFG Date Code Decoder

Postby Tazin on Thu Apr 18, 2013 11:20 pm

I've been messing around decoding the mfg dates for filter capacitors found in plexi era amps from manufacture's such as: RS, TCC, HUNTS, DALY, and ERIE. Here's what I've come up with so far which seems rather plausible. So, in order to prove, disprove, or fine tune my hypothesis below I could use some examples from you guys.

HUNTS and ERIE Date Codes:
The initial hypothesis was the code was read as Year-Week-Week, but after trying this on multiple amps it seems more likely that the code is read as Year-Month. Also, ERIE took over HUNTS somewhere around mid 1967 so ERIE filter capacitors use the same date code as HUNTS. In addition, it seems as though the use of the ERIE logo on the filter capacitors didn't seem to start until around 1969.
Basic date code translator is: WHITSUNDAY=1234567890

W = 1
H = 2
I = 3
T = 4
S = 5
U = 6
N = 7
D = 8
A = 9
Y = 0

Basic Example: N YS date code is: 1967-05 --> 1967 May

HUNTS & ERIE EXAMPLES:
D YI = 1968 March SB/12152, SB/12393, ST/10473, SB/12027
N YT = 1967 April S/10163
D YU = 1968 June S/11737
A YH = 1969 Febuary SA/10978 Test Date: 20/3/69
D YS = 1968 May SL/12xxx
N YU = 1967 June JMP SL/10390
N WW = 1967 November JMP S/11540
N WW = 1967 November JMP SL/12122
AWY = 1969 October Erie SL/A 10801
A YH = 1969 Febuary S/A10556
A YH = 1969 Febuary S/A10668
U YD = 1966 August SL/10019 the 8uF/150v
A YI = 1969 March SB/A10751 the Erie 32uF + 32uF/450v
/****************/

/****************/
TCC Capacitor Date codes. NOTE: Also works for RS Capacitors too.
A thru Z used except 'O'
YEARS
'Q' = 1959
'R' = 1960
'S' = 1961
'T' = 1962
'U' = 1963
'V' = 1964
'W' = 1965
'X' = 1966
'Y' = 1967
'Z' = 1968

MONTHS
'A' Jan
'B' Feb
'C' March
'D' April
'E' May
'F' June
'G' July
'H' August
'J' September
'K' October
'L' November
'M' December

Typical Date code: TCB/VK --> TCC Capacitor
Typical Date code: PXM --> RS Capacitor 32uF Axial
Typical Date code: ZB P --> RS Capacitor 100uF 450V Radial

Basic Example: VK = 1964 December, WD = 1965 April, VJ = 1964 September, VK = 1964 October, UH = 1963 August, UM = 1963 December,
WB = 1965 Febuary, WD = 1965 April, VL = 1964 November, WA = 1965 January, ZH = 1968 August

TCC CAPACITOR EXAMPLES:
TCB/YC = 1967 March JTM SB/10174
TCB/YC 1140 = 1967 March JTM S/10122
TCB/YH = 1967 August JMP S/11101
TCB/YL = 1967 November JMP S/11183
TCB/XD = 1966 April JTM S/10103
TCB/YC 1140 = 1967 March JTM S/10208
TCB/YC 1140 = 1967 March JTM S/10408
TCB/XD 9730 = 1966 April SL/10007
TCB/XD 9730 = 1966 April SL/10019
TCB/ZH 9730 = 1968 August ST/A10442


RS CAPACITOR EXAMPLES starting with the letter 'P'
PWJ = 1965 September Ser.6621
PWK = 1965 October Ser.6631, Super PA Ser.6630
PXE = 1966 May Ser.7047
PXH = 1966 August Ser.7026
PXL = 1966 November Ser.7213
PXM = 1966 December SL/10007, SL/10019
PYC = 1967 March
PYD = 1967 April SL/10165, SL/10277
PYF = 1967 June 32+32uF/350V Ser.7026
PYL = 1967 November ST/10358, SL10346

RS CAPACITOR EXAMPLES starting with the letter 'Z'
ZA P = 1968 January SL/10411, 32uF/450V Axial ST/10488
ZB P = 1968 Feburary SL/10103
ZM P = 1968 December S/11897
/*********/

/*********/
DALY Capacitors (1971 thru 1979)

YEARS
'Q' = 1971
'R' = 1972
'S' = 1973
'T' = 1974
'U' = 1975
'V' = 1976
'W' = 1977
'X' = 1978
'Y' = 1979

MONTHS
'A' Jan
'B' Feb
'C' March
'D' April
'E' May
'F' June
'G' July
'H' August
'J' September
'K' October
'L' November
'M' December

Typical Date Code: QJ --> DALY 50uF + 50uF/500v Multi-section Radial Cap.

DALY CAPACITOR EXAMPLES:
QJ = 1971 September T/A4509C Test Date: 4/Oct/71
QK = 1971 October S/A1267D Test Date: 15/1/72
QM = 1971 December S/A1130D Test Date: 11/1/72
/*********/

I'd also like to add that it seems quite common that the filter cap date be a couple of months earlier in date than the actual amp. One thing that still seems a bit out of place is the date code on the HUNTS 32+32uF/350v pre-amp capacitor found on the PTP board. These for some reason seem to basically all have the same date, so I'm not sure if they updated the silk-screen as often as they should have or perhaps there was an abundance of them in storage.....
Last edited by Tazin on Mon Apr 22, 2013 5:04 pm, edited 1 time in total.
Tazin
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Re: Filter Capacitor MFG Date Code Decoder

Postby Ned B on Fri Apr 19, 2013 2:06 am

Interesting and very in depth work. Do you feel there is significance to the Christian reference by using whitsunday other than it was a 10 letter word with no repeat letters?
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Re: Filter Capacitor MFG Date Code Decoder

Postby Tazin on Fri Apr 19, 2013 1:06 pm

I'm completely unfamiliar with the Christian reference to whitsunday.....What does it refer to?
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Re: Filter Capacitor MFG Date Code Decoder

Postby Gooch on Fri Apr 19, 2013 9:40 pm

Here's an old thread where we discussed the Daly date coding:

viewtopic.php?f=1&t=3340&hilit=daly
Dying ain't much of a living.
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Re: Filter Capacitor MFG Date Code Decoder

Postby jaywalker on Fri Nov 08, 2013 2:32 am

http://en.wikipedia.org/wiki/Whitsun <----- informational post regarding the topic at hand (lest someone gets their panties in a wad)

I used a similar "phrase code" in my business for certain sensitive information that was committed to paper or other forms of storage or transmitted over the air. Very secure method.
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