Further to Al's comments, if your Admiral was made before 1946 it won't appear in SAMS Photofacts (which started that year), but may appear in the Rider Perpetual Troubleshooters manuals.
Your model number might also appear on a printed paper glued to the inside of the cabinet, underneath. Whether plaque or paper, it should clearly show the word "Model" in front of that number. Other numbers might only be patent dates or chassis number. In some cases the chassis number is used in lieu of model number, to locate the schematics. It will be marked "Chassis" or simply "Ch." in front of the number. Frankly though, for your Admiral none of this should be needed. The loud hum problem you describe is cured simply by matching the replacement filter capacitor values to the original specs. Your originals are likely two capacitors that are combined in one cylindrical cardboard unit, rated between 30 and 50 microfarads at 150 volts, for which a pair of commonly available modern replacements of 47 MFD at 160 volts will work. Distortion can come from degraded smaller capacitors in your unit as well (the little wax covered paper cylinders in the range of .01 to .05 MFD typically), as well as a degraded cartridge. First step in determining whether these are further issues is to replace those larger filter capacitors and see if that clears up the problem. If you can solder properly (even many repair shops turn out questionable solder work), you can make this repair yourself. If you'd like to attempt it feel free to get in touch with me outside of this forum if you like, and I can advise you further on the parts, the replacement procedure and proper solder technique if needed. Thanks Al for the reminder of the hot potentiometer shafts on the Edison C2. I wonder if my C4 is that way (have never thought about it). Andrew On Sep 2, 2012, at 11:15 PM, [email protected] wrote: > > > Greetings Edward: > > I do all my own restorations. When it comes to anything electronic, the > first thing you need to know is the model number and serial number. From > that you can get to step 2, finding a schematic diagram. I would recommend > Peter Wall in San Francisco but he is a long way from you. There must be > someone in your area who will do the restoration but likely any professional > will charge a hefty fee. The model and serial are likely put on the back of > the cabinet or on a plaque attached to the radio or amplifier chassis. > > Andrew is quite correct about the capacitors being dead. The speakers of > that era used the field coil for a choke (inductor) to smooth out the > rectified DC in the power supply so when the caps are dead you get 60Hz hum > coming from the speaker. > > You really should never apply full operating current to any old TV or Radio > that hasn't worked in years. Bad things can happen quickly to delicate > components. > > Shops specializing in old electronics often have Photofacts or Wiley's > service bulletins. Again this starts with the model number. > > Lastly, don't go poking around when the unit is powered up. Some units like > my Edison C2 have HOT potentiometer shafts. I can tell you that to have a > few hundred volts surge through your body is no fun. These old units are > best safely brought up in line voltage slowly with a variac and made more > safe with an isolation transformer. > > Regards, > > Al > > > > > _______________________________________________ > Phono-L mailing list > http://phono-l.org > _______________________________________________ Phono-L mailing list http://phono-l.org
