Ron(UK) wrote in message
...
N Cook wrote:
Arfa Daily wrote in message
...

How about sticking them to the heatsink, with thermal glue such as is
used
to stick heatsinks to chips ?



http://uk.farnell.com/jsp/Mechanical...ives,+Tapes,+S

ealants+&+Service+Aids/FISCHER+ELEKTRONIK/WLK+5/displayProduct.jsp?sku=12117
23
or better yet



http://www.maplin.co.uk/Search.aspx?...source=15& SD
=Y
Arfa


Would need good cleaning off I suspect, before applying. I'm not sure
it
would cure a repeat drop.
Well yes, I'm sure it would need a good cleaning off - that's a given.
But
once you had stuck the device on there, I'm not at all sure that any
amount
of dropping would get it back off. Have you ever tried getting a
heatsink
thats glued, off a chip ? Do you fly to go on holiday ? Half that
aeroplane
is glued together ... We are not talking Evo Stik here. This is
industrial
spec glue, which is why it's eight quid a bottle ...


This is a likely generic fault scenario for all
such "live heatsink" amps that are only fixed to flexible polyester
pcb
board
so over a few years, you'd get full use out of your eight quid ...


Something similar to the tape was supposed to be keeping a duaghter
board
marked EB SUB ? (not on the Ashdown supplied schema, 4013 and 3 x 072)
fixed
to the preamp but dislodged in the same drop presumably, failed solder
joint/s leading to crackles.

I removed 2 nearby caps , 2 small holes ,to match cap pin spacing, in
cut
down lengths of cable-tie , and soldered back in, regooing and
positioning
the 2 shiftees. Volume was fading down after half hour of use,
presumably
because the NTC fan thermistor was staying at room temp and fan speed
not
upping with increasing heatsink temp.


So just live with the way it's designed, explain to the owner what
garbage
Trashdown gear is in the first place, explain that they mustn't drop
it,
and
rub your hands when they come trailing back with it in six months' time
...
d;~}

Arfa



At least Ashdown releases schema.
And bottle of expensive Snibbo has gone solid in sixth months, when next
required, is the usual outcome.

According to band manager it is a pointless exercise moaning at roadies.
There is also no point in sacking them as its a case of better the devil
you
know - any replacement/s will be the usual grunts plus the unknown
quantities.

Working with road crew all the time I know that most of them are pretty
careful with bands equipment but decent gear can stand a fair amount of
bashing about. Trashdown gear just isn't built for life on the road, it
might sound good, but construction wise it`s barely MI quality. Maybe
they should invest in some decent road cases, tho probably the cases
would be worth more than the gear that`s inside them.

Ron(UK)

This band's other Ashdown faired even worse, they managed to bend the 5/16
inch coach bolt that holds the big mains torrroid to the chassis, when they
dropped/threw that one.
At least the emitter resistors were not suspended off the board to rock
apart and the ps reservoir caps are locked together. But that unsupported
daughterboard is inexcusable, now braced back to 2 chassis anchors.

Going back to cleaning. I saw a documentary on the Boeing plane plant and
cleaning for those glues is a lot more than wiping with some meths.


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/