Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12) x

Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Philco 89B code 123 newbie
#12

Yes, 48 is a bypass cap always in place. Important because it also has a role in cutting down on parasitic oscillation. There may be a mistake in the value for #47. I think that it should be a 0.015 uF cap, not a 0.15uF. That would cut off too much treble with the tone control in the low position.

#4 on your pic is a 300 Ohm wirewound resistor that serves as the cathode bias resistor for the 44 RF and 44 IF tubes. There is a numbering mistake on the pictorial. The resistor should be labeled as #5.
According to the schematic, #5 is this 300 Ohm resistor and #4 is the multi-capacitor can. The cap that is shown as #4 on the schematic that parallels that resistor is listed as 0.09uF. A 0.1uf cap will do fine here. If the resistor is out of spec, a 300 Ohm1 Watt or 2 Watt resistor should do fine. I don't know why they used this type flexible wirewound resistor. It could be for space considerations or adding inductance because it was wirewound.

These multi-caps were an effort at streamlining assembly, as all of these caps are "bypass" caps, where one end connects to chassis ground and a wire for each individual cap goes to either a cathode resistor or a voltage divider that supplies a plate or screen voltage. These were easier to assemble and wire into the circuit than 5 individual caps. This was also the theory behind the bakelite blocks that Philco used. If one of these bypass caps was left out, oscillation or "motorboating (low freq oscillation) could occur.

BTW, the underside of the chassis, wiring, the tuner drum, etc. is in fantastic condition given its age. I have rarely seen coloring on cloth covered wire this nice on any set I own or have worked on, with the exception of a GE S-22A (RCA R7A), Ca 1931, that came from Utah, likely from a smoke free home.

"Do Justly, love Mercy and walk humbly with your God"- Micah 6:8
"Let us begin to do good"- St. Francis

Best Regards, 

MrFixr55


Messages In This Thread
Philco 89B code 123 newbie - by Kurt P - 09-13-2024, 02:44 AM
RE: Philco 89B code 123 newbie - by radiorich - 09-13-2024, 08:12 AM
RE: Philco 89B code 123 newbie - by MrFixr55 - 09-13-2024, 09:36 AM
RE: Philco 89B code 123 newbie - by Kurt P - 09-23-2024, 04:43 PM
RE: Philco 89B code 123 newbie - by Radioroslyn - 09-23-2024, 09:46 PM
RE: Philco 89B code 123 newbie - by MrFixr55 - 09-24-2024, 06:06 PM
RE: Philco 89B code 123 newbie - by Radioroslyn - 09-24-2024, 09:25 PM
RE: Philco 89B code 123 newbie - by MrFixr55 - 09-24-2024, 10:07 PM
RE: Philco 89B code 123 newbie - by Radioroslyn - 09-25-2024, 10:28 AM
RE: Philco 89B code 123 newbie - by Kurt P - 09-27-2024, 05:35 PM
RE: Philco 89B code 123 newbie - by Radioroslyn - 09-27-2024, 08:50 PM
RE: Philco 89B code 123 newbie - by MrFixr55 - 09-28-2024, 09:03 AM
RE: Philco 89B code 123 newbie - by Kurt P - 10-15-2024, 03:07 PM
RE: Philco 89B code 123 newbie - by Kurt P - 10-18-2024, 01:30 PM
RE: Philco 89B code 123 newbie - by RodB - 10-18-2024, 03:29 PM
RE: Philco 89B code 123 newbie - by Radioroslyn - 10-18-2024, 05:15 PM
Kurt P - by Kurt P - 10-19-2024, 11:59 AM
RE: Philco 89B code 123 newbie - by Kurt P - 10-21-2024, 08:25 PM
RE: Philco 89B code 123 newbie - by Radioroslyn - 10-22-2024, 11:25 AM
RE: Philco 89B code 123 newbie - by Kurt P - 11-06-2024, 09:04 PM
RE: Philco 89B code 123 newbie - by morzh - 11-06-2024, 10:55 PM
RE: Philco 89B code 123 newbie - by MrFixr55 - 11-06-2024, 10:57 PM
RE: Philco 89B code 123 newbie - by Kurt P - 11-09-2024, 03:42 PM
RE: Philco 89B code 123 newbie - by MrFixr55 - 11-09-2024, 04:26 PM



Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Philco 42-345 Restoration/Repair
RodB :beerchug:Vlad95 — 10:22 AM
Philco 42-345 Restoration/Repair
Vlad, you nailed it. Swiss and German roots.RodB — 09:54 AM
5U4 vs 5Z4 tubes
Well this is a Hallicrafters SX/9 circa 1936. No real issues so far although I dodged a real bullet with a cap that was...bridkarl — 07:59 AM
5U4 vs 5Z4 tubes
The pinout is the same but the 5U4 has a 3 amp filament, verses 2 amps or less on the 5Z4. I think that the pinout of a ...Arran — 12:04 AM
Philco 42-345 Restoration/Repair
By the way. osanders0311 Take a look here: Dial cord stringing Guides May be here you can fount correct string settin...Vlad95 — 11:15 PM
5U4 vs 5Z4 tubes
5U4 and 5Z4 almost identical. I think nothing happened if you left 5U4 instedad 5Z4 long time. Just heater current 5U4 ...Vlad95 — 11:02 PM
Philco 42-345 Restoration/Repair
Hello Vlad95 , Very Funny ! Sincerely Richardradiorich — 11:01 PM
Philco 42-345 Restoration/Repair
RodB You are European yourself   :evil: I'm Canadian for the last 30 years  :snowman: But not Yankee  :lol: Vlad95 — 10:49 PM
Philco 42-345 Restoration/Repair
The band switch selects different oscillator coils for the band selected. I would look for a bad connection in the switc...RodB — 10:31 PM
Philco 42-345 Restoration/Repair
Hang in there...PaulPaul Philco322 — 09:30 PM

[-]
Who's Online
There are currently 949 online users. [Complete List]
» 1 Member(s) | 948 Guest(s)
Avatar

>