While trying to replace my pots, I fucked up my already fucked up Jube and a new pc board is on the way!!!
Ordered a new potentiometer pc board, Part # M-PCBA-00168 from tubesandmore.com
Now for the Long Story:
Back in 2017, several GGF members purchased a 100watt, Marshall 2555x 50th Anniversary Jube.... they were on sale so, WTF, why not?
It turns out that many of those Jubes had bad pots installed in the Presence, Bass and Mid locations.
These three knobs, on my Jube, were were very tight and not easy to turn. Spraying them with Deoxy helped, but eventually they got so tight that the shafts actually broke off.
This is a common problem with the batch of Jubes from 2017 and there is a thread about it at marshallform.com.
The Marshall Forum mentioned that some people immediately returned their Jubes for a replacement but, I was not one of them!
A few weeks ago, two knob shafts finally broke off and I decided to remove the three bad pots (Presenece, Bass and Mid) and install new ones.
I ordered replacement pots from britishaudio.com in Tennessee. This issue is so common, that they have the three pots listed and available specifically for the 2555x.
https://britishaudio.com/collections/ma ... fier-parts
The failed pots are located on their own, secondary pc board and the board is easy to remove... pull off the knobs, unscrew the pot bolts, pull the chassis, unclip the three blocks of wires and pull the board out.
Easy peasy!!!
The hard part is removing the pots from the board and this is where I fucked up; by mangling the traces under the Bass pot....
My soldering iron doesn't get hot enough to remove the new, silver/tin solder that Marshall used on this amp.
I cleared most of the solder, but one pin, on the Bass pot, wouldn't budge so, I tried drilling it out and in the process, I also drilled out the trace.
Yes, I will be purchasing a Haiko soldering station (that hits 800 degree F) before I try anything like this again!!!
Moving right along, I went ahead and installed the new pots but, the damage was done and the amp crackled like it had an arching tube!!!
Now that I had a totally unusable Jube, I sent an email to Marshall in the UK, asking if they could sell me a replacement potentiometer pc board. A few days later, I got an email from their American distribution company, JAM Industries USA. JAM Industries provided me with the part number (M-PCBA-00168) and recommended that I contact tubesandmore.com (aka Antique Electronic Supply) to place the order.... I did so and now, a new, pre-populated pc board on the way!!! WOOO HOO!!!!
FYI: Britishaudio.com in TN can also order the pc board but, they responded after I had already ordered from tubesandmore.
Interestingly, British Audio said you can't order just the small, potentiometer board, because Marshall only sells both the main board and the pc board as a package. The price is $349 plus shipping.
We will see if tubesandmore sends me both boards, since they didn't mention this and I did pay $349 + shipping.
If any of you 2555x owners want to have a go at replacing the pots, I suggest cutting the pots with a Dremel (see below pic), allowing you to pull the pins out, one-at-a-time. After cutting the pot, you can simply heat the pins from the back and pull the pins out from the front. Then, using a solder-sucker and copper desoldering braid, it will be easy to clean the remaining solder out of each hole in the board.
Of course, I only realized how to safely remove the pots, AFTER I fucked things up!!!
Gut shot...
In the process of fucking up my already fucked up Jube...
The potentiometer board...
Where to cut the pot so you don't do what I done...
