Service Upgrades and a Detailed Look Inside an '84 Marshall JCM800 2203 Halfstack

A while back I acquired a very nice and clean 2203 halfstack from '84. This was a great year for the amps but not so much for the cabs as the G12M-70's have a pretty bad rap. This was a transitional year for both the cabinets and the heads.
The 2203 amplifier would first see the DI jack installed on the rear panel during this year. In 1984 the vertical input models would also be discontinued in favor of new construction methods which would put all the inputs horizontally as they would be mounted directly to the PCB. There is a lot of conjecture online about the vertical input models being better built and easier to work on... it's all nonsense. The main difference between models other than construction is that there are less 50/50 can capacitors in the 100W horizontal input version. We will save that comparison and the technical aspects between the two for another video.
1984 would also end production of the G12-65 and you would see many G12M-70 speakers fitted in cabinets with 260W badges meant for the G12-65. Fortunately the G12M-70 would be short lived and permanently replaced by the G12T-75 speaker.
I really love the stock 2203 sound so the preamp circuitry is left stock while I replace the electrolytic capacitors and make some improvements to the input shielding, heater circuit and ground scheme for maximum reliability and the least amount of unwanted noise.

Check out my website for more information www.purgasound.com

Celestion date codes and a T-number database can be found here
https://www.bygonetones.com/celestion...

Marshall date codes, would be the last letter in serial number
A July 1969 - Dec 1970
C 1971
D 1972
E 1973
F 1974
G 1975
H 1976
J 1977
K 1978
L 1979
M 1980
N 1981
P 1982
R 1983
S 1984
T 1985
U 1986
V 1987
W 1988
X 1989
Y 1990
Z 1991 - 1992