Bendix 55P3 Restoration

1. Bendix 55P3 Restoration Paul Pinyot. KB3LZP

2. You have to clean the shop some times! I choose between units.

3. Typical AA5. A Bendix 55P3.

4. Model, manufacturer and tube location on sticker. Sometimes the model number is inside or only a chassis number.

5. Tape or Gum Band a hard cardboard cover on the speaker to protect the cone. Screws in a pill bottle

6. Label Antenna wires

7. Ohm out antenna coil. It is part of a tuned circuit.

8. Check all coils and transformers for bad unopbtainium

9. IF continuity primary and secondary. Use schematic to find pins not in series with capacitors integral to the IF can.

10. Touch a 9 volt battery on the primary of the audio output transformer. If the speaker pops all is well. The primary, secondary and speaker voice coil. This does not work with eletrodynamic speakers.

11. Record you results. Green for good, Red for open

12. This is an emissions tube tester. Quicker than a Mutual conductance. The tube must work in the unit.

13. SHORT! Do not power up in chassis!

14. This tuning shaft oxidized concaved area would catch the dial cord. Remove and sand smooth 220 grit emery cloth

15. A dab of hi temp lithium grease give control a smooth feel.

16. Flush the tuning gang’s ball bearings with contact cleaner or denatured alcohol and replace the grease. Don’t get any grease on the capacitive fins!

17. Mr. Jingles left his mark here !@#%

18. Two section 40uf electrolytic capacitor. Wax/paper capacitors

19. Two caps of 40 uf 160 volts and one 200 uf at 50 volts

20. 4 post terminal strip that is screwed to the chassis. Do NOT use the 4th post as it is chassis ground and not B- or circuit ground. These caps do NOT connect to chassis ground! Two caps are parallel to make up 40uf. The other is a singe 47uf 160v standard value.

21. New electrolytic cap array screwed to chassis using original capacitor lead wires. This is an UL rated safety capacitor used for RF bypass. This cap and a parallel 220k resistor are connected from circuit ground B- to chassis ground and makes this a HOT chassis.

22. This cap will be replaced using hooks. Clip the cap close to the body leaving all of the lead wire.

23. Form a hook with the needle nose pliers to receive the complimentary hook of the replacement cap.

24. The new capacitor is the same or slightly larger in capacitance and is 630 volt rated. These wax/paper caps will only see up to 120 volts. 630 volts are used simply because of bulk purchasing discounts and minimizing inventory.

25. Place new cap lead wires in hooks, form into reverse hooks clip excess and crimp.

26. Crimp Crimped

27. Solder the connection.

29. Alligator jumper used to mark original capacitor’s lead wires. This comes in real handy for interruptions like the phone or lunch.

30. Spaghetti insulation is added. The replacement is smaller than the original. These lead wires will be curled on a stiff wire and slipped over the original lead wire in the chassis.

31. Home made tool using an Exacto knife handle and a cut off safety pin.

32. Roll lead around the pin.

34. Ends curled and trimmed. Slip these over the original lead wires and solder.

35. When heated the coil will often slip under the original spaghetti insulation. The spaghetti may close up over the coiled and solder splice.

36. To maintain a vintage appearance restuff the original capacitor.

37. This technique is used for a “museum” level restoration. An example is the $21,000, 16 tube Zenith 16-A-63 Stratosphere.

38. The new cap fits right into the original cardboard. Use paper slivers to fill the space. Seal with wax or Hot Melt glue.

39. Seal the ends with Hot Melt glue or wax, fresh or original. You can melt down all the cut out caps, that you have in your big jar, to maintain vintage wax. This radio did not have its capacitor re-stuffed. This is only how you would do it.

40. Shined up the cabinet with a power buffing wheel, rouge, Novis Polish and Glayzit.