[Trio] Power supply filter caps

[Ken\Marlene]

I've had to replace the Elna filter caps in both a JR-60 and a 9R-4J. =
They're usually dual 40 microfarad @ 300 VDC units in a metal can. These =
receivers are both 30+ years old, so it was to be expected. =
Unfortunately, replacements are quite hard to find, at least here in =
Canada.

 The unit from the 9R-4J measured 67 and 48 uFd, a sure sign that it was =
drying out. I've managed to rebuild these electrolytics using brand new =
22 uFd, 250 VDC axial lead caps from Philips. The Philips part number is =
042-13229. Four of these fit into the old Elna can quite easily.

 Remove and discard the plastic sleeve at the bottom of the can. =
Carefully uncrimp the bottom edge of the can where it folds over the =
rubber end piece.  With a little effort you can now pry the innards out =
of the can.

 Cut the aluminum foil leads right at the terminals and discard the =
innards. You might have to clean up the inside of the can with a knife =
(or screwdriver!).

 The original terminals (which are solderable) are secured with aluminum =
rivets (which are not solderable). Using a #60, 3 / 64 " or=20
1 mm drill bit and a high speed drill, drill a hole right through the =
centre of each rivet. These holes will pass the leads from the new =
electrolytics so that they can be soldered to the terminals.

 Each original 40 uFd cap is replaced by a pair of  22 uFd caps wired in =
parallel. Make sure that you get the polarity right! The crimped end of =
the Philips caps is the positive end. The wire leads on the Philips =
units are long enough that they can be paralled, brought out through the =
holes in the rivets and soldered to the terminals.

 Re-install the rubber end piece assembly into the can. Fold the bottom =
edge of the can over the rubber end piece and you're done! The =
'restored' capacitor can now be re-installed.

 I've replaced the other electrolytics in both receivers with Philips =
460 series polypropylene film capacitors. This is often enough to =
restore the receiver to something close to "like-new" performance.

73.      Ken, VE3FIT


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