Philco Restoration

Transcription

1 Philco Restoration 11/24/2012 Purchased on ebay for $51.50 plus shipping for total $ /4/2012 Began restoration. Purchased schematics from Philcorepairbench.com Schematic-PA RTS.pdf Schematic-PA RTS_Locations.pdf S_Alignment. pdf Inspected & photographed cabinet o Crack in edge of where left dial glass connects o Black stains on some portions of front and sides o Missing back left "footer" on bottom o Only 1 screw holding chassis to frame (back) Removed chassis & photographed o Missing light bulb o Bulb connector not connected to chassis, i.e. was loose and hanging in the tube area o Looks like still has all original capacitors

2 Removed dial glass - two mounting plates pressed dial gainst the wood opening held in place w/ some glue (or hardened rubber?) and two wood screws Removed staples holding cardboard & grill cloth. Grill cloth looks OK. Staples had 1/4 " length into wood

3 Began cleaning front of chassis & speaker o Knobs cleaned up w/ soap and water and small scrub brush. Tension springs in knobs removed during cleaning. o Front speaker felt that butts up against wood fram is unglued in some places; will glue w/ rubber cement. o Speaker cone has small tear; will repair w/ rubber cement. Above the speaker is a piece of paper that is used to diffuse llight from the bulb through the glass dial. It is yellowed & torn. Will remove and replace w/ white paper. 6 13/16" x 1 3/8" Removed vacuum tubes. o Note there was a 7B6 in place of 7C6 o Note 7B7 tube was labelled as "BAD" on the base of the tube. Cleaned lint out of tuning knob pulley and now it will not tune, i.e. the cord slips on the pulley. o Drawing for tuning cord position.

4 Removed #43 multisection capacitor mount to see what working voltage is on the can; it was 150vDC.

5 Clipped condensor #37 lead to access IF (2nd IF) xformer can so I can get internal can condensor value. Lead to #37 goes to pin #4 of 7B7. Removed 2nd IF xform can #27, 2 nuts under chassis and brass clip inside can which fits under coil tube and snaps into can.

6 After removing the IF can I realized you cannot put the can back on while the xformer is still soldered to the chassis. Removed electrolytic cap [20,20,10 uf] for restuffing o Red = 20 o Yellow = 20 o Green = 10 o Black = common Removed power cord to gain better access Power connected to left side of candohm resistor strip & center lug of on-off pot. Replaced 2.2 meg resistor #28 from between 7C6 pins 5 & 6. Replaced # uf cap Replaced all wax/paper caps Put heat shrink tubing on many of the wires. There were some that were still pliable rubber so did not replace them.

7 Powered up with dim bulb testor but the new #47 dial lamp blew. Found that candohm resistor was open/intermittent where it should be 40 ohms. Replaced the candohm with 80 (10 watt) and 40 ohm (5 watt) power resistors. Following power up again with dim bulb testor and isolation transformer, found there was no B+ voltage. Replaced the 35Z3 tube and got correct B+. Measured voltages and found incorrect voltage on 7C6 (7B6) plate (82v instead of specified 35v], but do get static through the speaker when volt meter probe is put on the plate. Replaced the 7B6 with a NOS 7C6 and also replaced the 7B7 that was labeled "BAD". With power up, stations on both AM and SW come in. Elected not to try to do alignment at this point. Cabinet Cleaned cabinet with GOJO and 0000 steel wool along with some mineral spirits. This eventually took off the black stains. Also removed the old decals this way. Finish seemed to remain intact nicely. Dirt and grime came off. Applied two rounds of Howards Restore-A-Finish (Walnut) to the cabinet with 0000 steel wool, wiped dry and let the cabinet dry for a couple hours. Finish came up nicely although there are some places on the top that the original lacquer had come off. Still, it looked good so elected to stop there. Decided not to try to glue or further repair the crack to the left of the dial glass. Applied decals, installed new reproduction dial glass, remounted the grill cloth and installed chassis.

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