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Philco 90 1-47 Triode
#20

@Terry, save some Mercon V for me, I am slipping too.  I also need new ball joints.

@Mike,  Icon_redface, Yeah, it is C24.  that is a multisection cap.  I have not done a 90, but I have done other Philcos of that vintage (20, 80, 89)

The good news-  The radio is unmolested and should be a good performer.

The bad news- The filter caps are likely shorted, the other caps (those bakelite thingies) and resistors are likely out of spec. 
These caps also short.

The really bad news-  The RF and 1st Detector transformers are prone to open coils due to reaction between the cellulose inter-coil insulators and the lacquer on the wires.  This is covered by several articles by Ron Ramirez and others on how to rewind these coils.

Here's what to do to check this out:
  1. Remove the tubes after verifying their location. Clean the dust off the chassis.  A leaf blower will work fine.  Windex will clean the tubes, but do so one at a time and re-mark the tube number if erased by the cleaning.
  2. Locate C52, the Line filter (the power wiring goes to this).  Disconnect the "caps" (Capacitors, otherwise referred to as condensers in early literature) inside the block by passing a drill through the rivet to sever the connections between the caps and the terminals the drill bit should be a size that is as close to the hole in the rivet as possible.  Do this because these caps can short and either make the chassis hot or short the power input.
  3.  "Ohm" the resistors.  They should be within 20% of the documented value.
  4. Reinstall all tubes except the Type 80 rectifier.  This will put a filament load on the transformer but not a lode on the Hi voltage "B+ windings.
  5. Carefully power up the set.  If you can put an ammeter in series, do so.  Verify the "heater" voltage for all tubes except the rectifier is 6V AC. (All tubes except the rectifier are in parallel.)  Check for leakage, or excessive heating of the transformer.  VERY Carefully verify the voltage between the 2 smaller "holes" in the 80 Rectifier socket.  There should be about 600-700 Volts AC between them.  Carefully verify the voltage between the 2 large holes in the 80 Rectifier socket.  There should be 5V AC between those contacts.  Power down the set and remove the tubes.
  6. Replace ALL caps starting with the filter caps.  There are 2 ways to do this.  The quick way is to just replace them. do not "bridge" them.  For the Bakelite caps, pass a drill bit through the rivets to sever the connections as in Step 2, above.  Solder the replacements to the tabs.  Some of these bakelite blocks contain 2 caps or contain a cap and resistor.  The true Restorer's way is to hollow out the blocks and insert the new caps and resistors if exist in these blocks.  The true Restorer will also "stuff" the filter caps with new ones.  There are articles on how to do this on the Phorum.  Do not forget to replace the 2 "Bypass Cap" blocks and the caps in the tone control.
  7. Replace any out of spec resistors.
  8. Add tubes, connect the speaker and an antenna, and take the radio for a test run.  If you have a Variac or a "dim bulb" tester, use them (See articles in the Phorum for details).  Watch the 80 and other tubes for flashing, indicating shorts.  Watch the 47.  If the screen grid or plate start glowing, shut down.
  9. You should be rewarded with static or stations.
  10. Finish cleanup and restoration.
  11. Enjoy your handiwork, and say a prayer for the folks who built, sold, bought and used this radio, as they are all likely deceased.  Think of all of the historical broadcasts that were received by this radio.  Be sure to play it relatively often.
  12. Keep us all posted on the progress!!
 

"Do Justly, love Mercy and walk humbly with your God"- Micah 6:8
Best Regards, 

MrFixr55


Messages In This Thread
Philco 90 1-47 Triode - by Mike_RF - 06-25-2023, 04:02 PM
RE: Philco 90 1-47 Triode - by morzh - 06-25-2023, 06:10 PM
RE: Philco 90 1-47 Triode - by Mike_RF - 06-25-2023, 06:18 PM
RE: Philco 90 1-47 Triode - by Mike_RF - 06-25-2023, 07:28 PM
RE: Philco 90 1-47 Triode - by Radioroslyn - 06-25-2023, 07:43 PM
RE: Philco 90 1-47 Triode - by MrFixr55 - 06-25-2023, 08:06 PM
RE: Philco 90 1-47 Triode - by Mike_RF - 06-25-2023, 08:07 PM
RE: Philco 90 1-47 Triode - by Mike_RF - 06-25-2023, 08:11 PM
RE: Philco 90 1-47 Triode - by morzh - 06-25-2023, 08:31 PM
RE: Philco 90 1-47 Triode - by Mike_RF - 06-25-2023, 08:33 PM
RE: Philco 90 1-47 Triode - by Radioroslyn - 06-25-2023, 08:45 PM
RE: Philco 90 1-47 Triode - by DaleHCook - 06-25-2023, 08:50 PM
RE: Philco 90 1-47 Triode - by Radioroslyn - 06-25-2023, 08:59 PM
RE: Philco 90 1-47 Triode - by Mike_RF - 06-25-2023, 09:04 PM
RE: Philco 90 1-47 Triode - by MrFixr55 - 06-25-2023, 09:12 PM
RE: Philco 90 1-47 Triode - by Mike_RF - 06-25-2023, 09:18 PM
RE: Philco 90 1-47 Triode - by MrFixr55 - 06-25-2023, 09:22 PM
RE: Philco 90 1-47 Triode - by Mike_RF - 06-25-2023, 09:25 PM
RE: Philco 90 1-47 Triode - by Radioroslyn - 06-26-2023, 07:31 AM
RE: Philco 90 1-47 Triode - by MrFixr55 - 06-26-2023, 10:32 AM
RE: Philco 90 1-47 Triode - by Mike_RF - 06-26-2023, 02:15 PM
RE: Philco 90 1-47 Triode - by morzh - 06-26-2023, 05:46 PM
RE: Philco 90 1-47 Triode - by MrFixr55 - 06-26-2023, 06:23 PM
RE: Philco 90 1-47 Triode - by Mike_RF - 06-26-2023, 07:28 PM
RE: Philco 90 1-47 Triode - by GarySP - 06-26-2023, 07:59 PM
RE: Philco 90 1-47 Triode - by MrFixr55 - 06-26-2023, 08:16 PM
RE: Philco 90 1-47 Triode - by RodB - 06-26-2023, 10:08 PM
RE: Philco 90 1-47 Triode - by Radioroslyn - 06-27-2023, 06:26 AM
RE: Philco 90 1-47 Triode - by Ron Ramirez - 06-27-2023, 07:35 AM
RE: Philco 90 1-47 Triode - by Mike_RF - 06-27-2023, 09:18 AM
RE: Philco 90 1-47 Triode - by Ron Ramirez - 06-27-2023, 09:51 AM
RE: Philco 90 1-47 Triode - by morzh - 06-27-2023, 10:02 AM
RE: Philco 90 1-47 Triode - by Mike_RF - 06-27-2023, 10:05 AM
RE: Philco 90 1-47 Triode - by Ron Ramirez - 06-27-2023, 10:06 AM
RE: Philco 90 1-47 Triode - by Mike_RF - 06-27-2023, 10:30 AM
RE: Philco 90 1-47 Triode - by morzh - 06-27-2023, 10:34 AM
RE: Philco 90 1-47 Triode - by Ron Ramirez - 06-27-2023, 10:42 AM
RE: Philco 90 1-47 Triode - by Ron Ramirez - 06-27-2023, 10:44 AM
RE: Philco 90 1-47 Triode - by Ron Ramirez - 06-27-2023, 10:54 AM
RE: Philco 90 1-47 Triode - by Mike_RF - 06-27-2023, 11:03 AM
RE: Philco 90 1-47 Triode - by morzh - 06-27-2023, 11:10 AM
RE: Philco 90 1-47 Triode - by Ron Ramirez - 06-27-2023, 12:07 PM
RE: Philco 90 1-47 Triode - by Mike_RF - 06-27-2023, 12:11 PM
RE: Philco 90 1-47 Triode - by Ron Ramirez - 06-27-2023, 12:22 PM
RE: Philco 90 1-47 Triode - by morzh - 06-27-2023, 12:23 PM
RE: Philco 90 1-47 Triode - by Ron Ramirez - 06-27-2023, 12:27 PM
RE: Philco 90 1-47 Triode - by Ron Ramirez - 06-27-2023, 12:34 PM
RE: Philco 90 1-47 Triode - by Mike_RF - 06-27-2023, 12:34 PM
RE: Philco 90 1-47 Triode - by Mike_RF - 06-27-2023, 12:37 PM
RE: Philco 90 1-47 Triode - by Ron Ramirez - 06-27-2023, 12:39 PM
RE: Philco 90 1-47 Triode - by Mike_RF - 06-27-2023, 12:53 PM
RE: Philco 90 1-47 Triode - by Radioroslyn - 06-27-2023, 01:07 PM
RE: Philco 90 1-47 Triode - by Mike_RF - 06-27-2023, 01:13 PM
RE: Philco 90 1-47 Triode - by Radioroslyn - 06-27-2023, 01:42 PM
RE: Philco 90 1-47 Triode - by morzh - 06-27-2023, 01:43 PM
RE: Philco 90 1-47 Triode - by Mike_RF - 06-27-2023, 07:10 PM
RE: Philco 90 1-47 Triode - by Ron Ramirez - 06-28-2023, 06:07 AM
RE: Philco 90 1-47 Triode - by morzh - 06-28-2023, 09:33 AM
RE: Philco 90 1-47 Triode - by Ron Ramirez - 06-28-2023, 09:44 AM
RE: Philco 90 1-47 Triode - by morzh - 06-28-2023, 11:55 AM
RE: Philco 90 1-47 Triode - by Mike_RF - 06-28-2023, 04:12 PM
RE: Philco 90 1-47 Triode - by Ron Ramirez - 06-29-2023, 07:24 AM
RE: Philco 90 1-47 Triode - by MrFixr55 - 06-29-2023, 05:02 PM
RE: Philco 90 1-47 Triode - by Mike_RF - 12-21-2023, 10:40 PM
RE: Philco 90 1-47 Triode - by Radioroslyn - 12-21-2023, 11:34 PM
RE: Philco 90 1-47 Triode - by RodB - 12-22-2023, 09:50 AM
RE: Philco 90 1-47 Triode - by GarySP - 12-22-2023, 10:04 AM
RE: Philco 90 1-47 Triode - by Mike_RF - 12-22-2023, 10:08 AM
RE: Philco 90 1-47 Triode - by Mike_RF - 12-22-2023, 10:10 AM
RE: Philco 90 1-47 Triode - by morzh - 12-22-2023, 10:28 AM
RE: Philco 90 1-47 Triode - by Radioroslyn - 12-22-2023, 12:31 PM
RE: Philco 90 1-47 Triode - by Radioroslyn - 12-22-2023, 12:55 PM
RE: Philco 90 1-47 Triode - by RodB - 12-22-2023, 06:20 PM
RE: Philco 90 1-47 Triode - by Mike_RF - 12-24-2023, 05:35 PM
RE: Philco 90 1-47 Triode - by RodB - 12-24-2023, 08:56 PM
RE: Philco 90 1-47 Triode - by Radioroslyn - 12-24-2023, 10:32 PM



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