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

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

An Introduction and a Philco 90 issue.
#46

Doesn't the wire from terminal 3 go to ground through cap 35 or is my schematic reading inexperience on full display here?
#47

Here is the schematic I am looking at   Early Schematics – Philco Library (philcoradio.com)    (scroll down to 90 mid version) In this schematic there is a cap number 38 but, unless the cap is shorted, it won't change the reading.

M R Radios   C M Tubes
#48

OK that's the schematic I have.
#49

OK I was doing something stupid.  The wire from terminal 3 is fine...it reads infinite resistance to ground.  The wire from BC resistor terminal 4 is the same readings as before...90.4k ohms with the speaker unplugged...3200 ohms with the speaker plugged in.

Pics show these 2 readings, the speaker socket and the general area around the speaker socket.  All tubes are out.  In the last pic, that small black box attachment is for a 1/4" jack input for Bluetooth and similar input.  Pretty sure it's not an issue.  Radio and it worked fine before.


Attached Files Image(s)
               
#50

Chris, when you recapped the chassis, did you replace the caps in the tone control?

M R Radios   C M Tubes
#51

No I did not...I just sprayed contact cleaner on the 3 tabs and worked the controls
#52

OK, with the speaker plugged in, repeat the resistance check on wire 4. This time, turn the tone control to each position while checking.

M R Radios   C M Tubes
#53

Steve...it is 3200 ohms in all 3 positions on the tone control
#54

The tone control should have four positions. When the control is fully counter clock-wise you still get 32K?

M R Radios   C M Tubes
#55

Yes 3.2k...3200 ohms...not 32k
#56

Yes, I meant 3.2K.  Take resistance measurements on all speaker plug terminals first with the speaker plugged in and again with the speaker unplugged.

Steve

M R Radios   C M Tubes
#57

OK starting on speaker socket that is connected to BC terminal 4 and going clockwise.

Speaker plugged in:
1. 3200 ohms
2. Infinity
3. 98k ohms
4. 20 ohms

Speaker unplugged:
1. 90.6k ohms
2. Infinity
3. Infinity
4. 22 ohms
#58

The B+ line (speaker socket terminal 4) is shorted. You will need to trace that line all the way through.

Steve

M R Radios   C M Tubes
#59

Will do...thanks so much Steve...I'll get back to you. It's socket 4, the one that's reading 20 ohms plugged or unplugged correct?
#60

Yes, the one reads 20 ohms

M R Radios   C M Tubes




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Philco 42-345 Restoration/Repair
Vlad95, Thank you for the stringing guides and wow there are so manyosanders0311 — 06:01 PM
5U4 vs 5Z4 tubes
A pre war Hallicrafters, and an early one too, very nice! 1936 is pretty early for metal tubes too, which would explain ...Arran — 05:58 PM
Philco 42-345 Restoration/Repair
Thanks Rod, "When you hear the background hiss and no station it usually indicates that the oscillator quit" ...osanders0311 — 05:52 PM
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

[-]
Who's Online
There are currently 1365 online users. [Complete List]
» 1 Member(s) | 1364 Guest(s)
Avatar

>