Ron(UK) wrote in message
...
Heinz Schmitz wrote:
N Cook wrote:
http://home.graffiti.net/diverse:graffiti.net/clip.jpg
Looks like when the replacement transistor isn't yet soldered
to the board you can lower it enough onto the board to lever
open the spring and shift the transistor upwards under it.
Messy procedure, though, with heat conducting paste applied.
I would seriously consider to mark the hole of the transistor onto the
heat sink, take that off the board, drill a decent hole and to secure
the transistor onto the heat sink with a screw and washer like it was
always done in valuable devices :-).
I bet that during manufacture, the devices are fitted to the heatsink
first then the whole sink assembly fitted to the circuit board and
soldered up by hand. I`ve seen it before where one bad transistor was
impossible to remove without unsoldering them all and lifting them away
with the metalwork.
Ron(UK)
www.lunevalleyaudio.com
Email reply from the amp maker's engineer
"As to the spring clips, there is no real way of removing and refitting
those, except by sliding them on to the heatsink slots. That can only be
done when loose (no devices
in place ).
Hence, they have to be mounted on to the heatsinks before sliding
them over the devices."
My bit of (clothes line peg) wedge and ptfe sheet method did work but if the
applied force along the slot, is not axial to it then the high-C steel clips
easily dig into the aluminium and jam fast. I found a large pair of
engineers cramps would gradually inch it across, taking up the slack every
few mm , and starting again. Just another thought, with a pair of large
sewing thimbles on opposing finger/thumb you may be able to use enough
finger pressure to slide the clip up the wedge.
But otherwise matter of desoldering the power devices and removing the
heatsink with trannies and then the trannies can be easily slid out from
under the springs.
--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/