It would be better to do an ESR test on the electrolytics before replacing
some that might still be good. On direct conversion receivers, some care
is needed to avoid picking up hum from a power supply anyway. On separate
supplies, twisted power leads are needed. Older supplies which power direct
conversion reception need 0.01 bypass caps across diodes of bridge
rectifiers to avoid hum pickup or AM station pickup.
You can clip one end of an electrolytic, then power it from a supply and
insert a current meter in series with the clipped leads, observing polarity
before applying power, and read the leakage current. Web capacitor pages
have appli. notes on allowable ripple as do catalogs. Most axial leaded
caps have enough slack to make a hook in each clipped lead for resoldering.
Other splices have been done with coils of bare copper solid wire about the
size of telephone wire, (no 26) made into a bright copper coil spring which
then can be soldered to both cut ends.
The vinyl may just have lost its plasticizer with age and shrunk, not
uncommon. Flooring stores or hobby stores, or sign companies are possible
sources of replacement colored plastic in wood pattern.
73, Stuart K5KVH
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