Right then, back up and running....and a saga. Oh how we love a saga !
As promised @LennyP there's a pic of the busted pot. Or at least the biggest bits
Also the head with the fascia off. I like the bent bits of silver metal to keep the light from the lamps in the right places to illuminate the labels and logo from behind.
So then...why the saga ? And why did he have the main board out if he was just changing a pot ?
Well, after putting the new pot in, strange things started (and didn't start) happening. The 3-LED level indicator didn't work and the EQ was in a mess - constant cracking in the background when it was engaged and moving the sliders did a) nothing b) made the sound get distorted and disappear or c) acted as strange volume controls. Harrrumph #1
Next step - I pulled the EQ/Level indicator board and gave all the sliders a thorough clean. They were filthy. Two rounds of switch cleaner and isopropyl alcohol were needed to get them ship-shape. Checked the board and reflowed some of the less savoury connections. Back together....still the same problem. Harrumph #2.
After some pondering of the circuit diagram and removing the feeds to and from the EQ board I realise that it's most likely the problem is on the main PCB, not the front slider/level indicator board. Time to get some proper disassembly done (Pic 3). It's built like a tank, so this was quite good fun.
Soldering iron on, pot of tea made and some Suzanne Vega to listen to and I started on the clean-up and partial reflow. Did all the pots and switches as well as a couple of strange-looking solder joints in the EQ circuit. Everything else looked very solid so rather than make problems I stopped there and reassambled.
And it works ! Whoo-yay !
Sounds spiffing too, still has the background noise on standby, but it's not too bad and I may still give it another service at a later date, but for now Matthew, I'm off to be Tony Levin for a bit