Blown mains fuse, cracked through the ceramic and sand and blackened
internal surface. Someone had replaced the 1A HT fuse with 3.1A at some
point, which was ok. Someone had managed to strip the internal
"screening" card from the staples holding it the cab base. Metal side to
the inside, only the vaguest of plastic sheet insulation over it and
could have been touching anything. No tag for an earth point/wire that I
can see anyway, so that will not be going back inside. All logo/printing
of each valve looks balanced thermal degradation (slight) but these
Electro Harmonix all dated 0611 have flattened domes at the getter end.
There is a recessed rough dimple in each of these , all
off centre so unlikely at manufacture, signs of overheating? I,ve not
seen these rather raggedy dimples before but I cannot believe the
dimples would be so remarkably similar if the flat part of the tube was
heated enough to start collapsing inwards (valves with base at bottom ,
ie not inverted orientation in use). Valve bases look normal, no
colourations or discoloured valve Rs inside etc .
No EL34 tested yet but the first valve I remove, the forked contact for
grid pin 5 takes a 2.5mm drill shank inserted but touches a 2.55mm one.
Previous Hiwatt, different model, stopped bouncing back after I replaced
all the p5 forks with proper 30 yearold NOS ones . That one had forks
with about 2.2/2.3mm forks that were suspect. That Hiwatt had wired in
sockets but this is pcb type, so how to remove individual pins without
removing whole sockets? Replacing complete 2007 sockets with 2013 ones
seems a hiding to nothing. For good measure RoHS/PbF stickers aplenty.
Owner queries whether it is due to being borrowed by a wannabe bass
guitarist who uses extra mass per unit length strings on ordinary
electric guitar, for some musical style purpose.