Marshall Valvestate 8040 sound dies

[lindfieldchris]

Hi All,
I've just taken delivery of a 2nd hand 8040. Sounds GREAT, except after 10 minutes the sound starts to die (comes and goes). It happens both in normal and boost channel (so it can't be the boost pre-amp valve, right !?). Any ideas ? Also, boost gain knob causes extreme sound "bangs" when turned. Can one clean the pots or is it a replacement jobbie.

..regards Chris (chris.ruberg@awta.com.au or chris.ruberg@tpgi.com.au)
Thanks in advance for assistance.

[Gtr_tech]

Hi All,
I've just taken delivery of a 2nd hand 8040. Sounds GREAT, except after 10 minutes the sound starts to die (comes and goes). It happens both in normal and boost channel (so it can't be the boost pre-amp valve, right !?). Any ideas ? Also, boost gain knob causes extreme sound "bangs" when turned. Can one clean the pots or is it a replacement jobbie.

..regards Chris (chris.ruberg@awta.com.au or chris.ruberg@tpgi.com.au)
Thanks in advance for assistance.

Clean the noisy pot, and clean the loop jacks. Signal goes through those on the way to the output section, so when there's nothing plugged into them they are supposed to direct signal through them via the shorting contacts. Possible the solder is cracked on them also (or elsewhere on the pcb).