CODE 50 faulty power supply



Marshall user since early time, I work also in electronics repairs.

A customer brought me a faulty code 50 power amp. Is there any way to get a new power supply from spare parts to replace it ? I thought replace the original PS with a standard one but the original one gives 2 power supplies: main power an bluetooth power.
In the worst case where we cannot find spare parts, it is possible to get schematics or at least the values of the voltages ?

It will be cool to bring back to life this amazing stuff from a ledgendary brand

Thanks in advance

asked 07 Aug 2019 at 11:18 PM

Sébastien GUINLE
Hi Sensatioa 2016 model and it looks like it could be a common fault . The power from mains was terminating at choke 1 on the power supply board.She I desoldered this it fell in half .It appears that the cage material is very brittle and is liable to crack when the pins are pinched to hold the device on the board.This leads to a crack and eventually the 2 wires break loose from the pins . resulting directly n a dead amp. Desolder ,clean the enamel off the ends of the wire and tin . Superglue the plastic frame back together and resolder the tinned wires to the pins . This is a 1:1 choke so it doesn't matter which way it goes back!in. Resolder the pins to the PCB ensuring not too much heat to undo the soldering repair and the amp should come alive again !
Just fixed the power supply of o
- George Robartes 08 Aug 2019 at 05:14 PM
Answers: 2


Hi Sabastien,

Can you email our team

Marshall Support

answered 08 Aug 2019 at 02:38 PM



Just came across this and I suspect that you have resolved this issue by now. I recently had the same problem and found from Marshall that the spare parts for this 2016 amp are no longer available and they have no alternatives or schematics avaialble as the subassemblies were soursed as OEM items. I did a bit of investigating and with some help have found that the supplies needed are 3.3v at 0.5A for the main board ( 5 way header) and 24v at 5A for the power amp on the yellow + and white -  wires. To avoid noise on the speaker output these 2 supplies need to be isolated. They share a 0v connection on the board but connecting them at the PSU creates some sort of interference loop that can be clearly heard as a high pitch buzz on the audio output. I hope this information will be of use toa others who have this issue and want to repair their amp.

answered 06 Oct 2020 at 01:45 PM

tony scragg
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