In Reply to: You need to replace all the caps posted by Chris O on June 23, 2003 at 05:28:29:
One of the important concerns are the electrolytic power supply capacitors: Those can go leaky over time ('specially this kind of time!). Some of the symptoms to look for include, low B+ voltages, excessive hum, etc. But! I have an old Sears console I restored (built in the 1940s)with PSU capacitors that have worked fine. Those capacitors can very often be brought back into respectable service by way of a variac. This is simply a variable transformer which can be used to bring the voltage up very slowly over a long period of time. There is a general sort of 'rule' that all old electrolytics and signal capacitors (usually paper in oil types) should be replaced for best performance. If you do that, I might consider leaving the old origianl can-type capacitors in place (but disconnected from the cirucuit), and usue smaller modern counterparts inside the chassis. This way you can keep the original appearance of the amplifier.If you can get a copy of the schematic or know what to look for, identify the type of high voltage rectifier being used. If it uses an old 'Selenium' type rectifier, that should be replaced with modern diodes of the correct current and voltage requirements.
But! (I have to say this...sorry...)if you don't have experience working with equipment, let someone else do the work who does.
Have fun! Sounds like a great project!
Erik
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