Revisited: My Marshall JCM 2000 DSL100-
I finally was able to get my amp to Keith Fain, a retired electronics tech out of Beckley, West Virginia to repair the 8 ohm input jack, clean out the chassis for dust and to test the main board for the notorious bias drift these model amps were known to have from time to time.
And since I was not in any hurry to get it back, I left it in the capable hands of Keith on March 16th and awaited word that the work was complete. I got my first update from Keith around April 8th, he sent me a email with an image of the main board, shortly thereafter we spoke by phone about what his first thoughts were on the main board.
Surprisingly the main board showed no signs of scorching or burns, being an amp of 25 years old, and being pre-2005, the year the bias drift issue was resolved. The board was clean. Keith went on to assure me that not all the PCB boards were faulty, that some boards never had a bias drift issue. Marshall UK reaffirmed this via email to me when I was seeking info on the faulty boards, and what lots in the production line were good and bad, they too assured me not all boards were bad, and it was possible I had a good one. Keith did however change the rear input jack, and found the old one still inside the chassis, by the looks of it 3 of the 4 connecters were missing, while the last one was folded underneath (see photo below), so my take is the input connecter was just rattling around.
Once the initial work was completed and Keith was set to test the amp, This when he discovered a humming (loud) when he powered it up, the hum was even apparent when he plugs a cable into the front jack., it didn’t take long for him to find the Culprit. It was a C-46 capacitator. Keith replaced it with a slightly higher voltage, this eliminated the hum, and he set the bias , and it was rock solid. This capacitor was the only piece on the main board Keith had found that showed some burns. (see photo below.) He also repaired the solder joints on the impedance selector switch that was causing the amp to cut out with vibration.
I finally brought it home on April 28th. I am thankful Keith was so detailed and kept me in the loop throughout the whole process, He could have done what I requested, which was to clean the chassis and change the input jack and I would have discovered the hum, not knowing what it was or what was causing it.
I cleaned the tolex with some leather cleaner and changed out the broken handle on it, My Marshall JCM 2000 DSL100, has a new lease on life.
Next blog will be more than likely a play through, till next time, I’ll post some important links below. You can contact Keith Farin per his Facebook page below.
