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

model 48 464
#1

I am having trouble restoring the model 48 464  

I have done the following

recapped
All tubes good 
tested resistance and  voltage readings  as per schematics form John F Ryder publication all good 

I get lots of noise ie static but do not  receive  stations .

Any suggestions ?
Thanks
#2

Have you performed the alignment procedure?
Do you have a SG?

You need to try to align, and if it does not, see if there is an open RF coil somewhere.
You need to put a signal through, from Antenna to the Speaker.

Noise/static is good. It means your tubes are mostly OK, your power/filters are OK.

People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
#3

For those of you following at home here's the info: https://philcoradio.com/library/download...8-1949.pdf

I picked up the same set a yr or so ago but it was the am/fm model and it was missing a chunk out of it's side. It was on the table that said FREE and it was 3:00am so I didn't give a good going over. It also came w/a model 84 which was a mouse house but had a good spkr...

When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!

Terry
#4

Thanks for suggestion 

Yes I have a rf signal generator and it also has an audio generator.
Tried the alignment procedure but could not get any signal after the first step. i then noticed that there are trouble shooting procedures for the radio as per attached. section 1 measuring voltage checked out 
section2 revealed no signal . I checked the resisters since the caps and tubes are good and R203 reads 586 K verses the parts  list of 470 K and R204 read 233K vs 130 ohms Its gets weirder .The next step for section 3 shows  in figure 3 C307 (.05mf) connecting from pin 5 on the 50 A5 to pin 3 on the 7b7  it does not show this on the schemo. the current wiring is pin 2 of the 50 with a .02 mf connected to pin 5 of the 7b7.

I am very carful when replacing caps .I don't remove the old leads from the pin  entirely. I cut the lead from the old cap and connect to that lead so i dont wire to the wrong pin. What  controls the figure 3 or the schemo?  

Also  the rf coils do have continuity and seem ok


Attached Files
.pdf Scan2023-11-20_145151.pdf Size: 1.5 MB  Downloads: 161
#5

I'm surprised that if the cathode resistor on the 50a5 measures 233K that you would have any audio at all. Do you have the proper voltages coming from the power supply (110vdc & 92vdc) more or less?

When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!

Terry
#6

yes the voltages are correct When i tested for them I used a Variac to ensure the the line voltage was 117 volts as per the testing protocol .
#7

Ok so if you measure the dc voltage from the cathode of the 50A5 (+) and B- to the negative meter lead. Should see about 6vdc there if the resistor is 130 ohms. If it's 233K it's going to be a whole lot more like 30 or 40v. This will cause the tube not to conduct. Replace w/a 1 or 2 w replacement.

When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!

Terry
#8

I rechecked the BC & Sw oscillator more carefully with a magnifying glass. Sure enough one of the  hair thin wires to one of the  posts was disconnected I reconnected and now get two to three AM stations which isn't too bad since i am in a basement with no exterior antenna. Additionally  i checked R203 ,650 k vs 470 k on schemo R204 was 257vs 130 on schemo . I replaced both and reception is much better . Still trying to realign but cant get alignment signals to the radio. 

You have been tremendously helpful  to this newbie !




Users browsing this thread:
[-]
Recent Posts
Philco 610B oscillator wiring
Thanks Terry. After checking my notes I think I recorded about -10v at the 6A7 G4/control grid. The screen grid (G3 &...Tubester — 05:59 PM
The list of my radio & TV collection!
Magical chords of forgotten melodies, old nostalgic music on an old radio... Saturday night blues on the Mid-Waves on an...RadioSvit — 12:20 PM
Philco 42-345 Restoration/Repair
Thank you MrFixr55 the issue with this radio is that the internal coil antenna is missing and there was a wire in its pl...osanders0311 — 11:34 AM
Philco 610B oscillator wiring
Regarding the oscillator circuit which is comprised of the 6A7's cathode, control grid, and screen grid. These elements ...Radioroslyn — 10:33 AM
Philco 42-345 Restoration/Repair
Hi OSanders, First off, welcome to the Philco Phorum where Phine Phamily-Phriendly Pholks Phull of Philco Phacts and P...MrFixr55 — 08:41 AM
Philco 42-345 Restoration/Repair
Today I've been reading through the site trying to learn more about this radio. I also soldered the lose power cord cabl...osanders0311 — 08:24 PM
Philco 610B oscillator wiring
Thanks David! I do have that same later prodution model 610 schematic. I've also studied the Philco service bulletins fo...Tubester — 08:12 PM
Philco 610B oscillator wiring
Some info from Beitmans says late production. David   David — 06:06 PM
Restoring Philco 96
Oh wow! Just found this thread.  Brings me back to early days on this phorum.  I did a 96 back in 2017.  Thread here: ...rfeenstra — 06:05 PM
Philco 610B oscillator wiring
Thanks for the replies. It's not the really the hum that I am after. Just trying to understand why only the shortwave ba...Tubester — 04:01 PM

[-]
Who's Online
There are currently 2506 online users. [Complete List]
» 2 Member(s) | 2504 Guest(s)
AvatarAvatar

>