Meat Plow wrote in message
...
On Fri, 10 Jul 2009 17:12:08 +0100, "N_Cook" wrote:
Mechanical problems that need sorting before the electrics or will
recur.
Each channel has 2 "daughter " board output arrays with power rails via
the
aluminium hex bar standoffs. One end has the screws nicely soldered on to
the main board conductor traces, but these standoff boards just screwed
against polyester pcb board, no star washers, contact (in theory) is on
the
other side of the board, but not with loose screws. This amp is used in
alternately both damp and dusty environment so inside looks more like 20
yearold, aluminium corrosion etc.
Any mod better than cleaning faces and adding star washers ?
Also the clinch nuts that hold the pa boards away from the top and bottom
covers are just clinched into pcb polyester so easily turn and work
loose,
any mod for that ?
are they called clinch nuts in USA ?
Would be nice to see some pictures of what you are describing. Appears
though that it's a more modernized and moderately redesigned
incarnation of the old CS series amps. Your mods sound reasonable.
Don't know quite what you mean by clinch nuts.
This amp is 30Kg in weight and because the clinch nuts are so small and
flexible top panel, so close to the pcb, someone has post-factory lined the
panel with sticky thick plastic sheet. You cannot extend the "nuts" without
modifying the single internal bracing metal (full-on engineering).
Clinch nut
http://imgs.tootoo.com/1c/30/1c301bb...6ca0f5266b.jpg
fine if the bolt is pulling the clinch into the polyester but here, with
movement (not used in racking) and flexing can pull these clinches
out/loosen them.
I'm thinking anvil , flat-head steel screw threaded-in to protect the
aluminium and then ground down tip old cross-head screw driver hex-bit
hammered on the internal aluminium ring to deform 4 points out into the
polyester, on all the clinch nut/standoffs.
For the daughter boards, longer screws and star washer under the heads. And
non-ferrous star washer on the electrical side between aluminium pillar and
lead'tin/copper, but stainless steel or chromed brass for this position ?
schematic is at eeserviceinfo
--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/