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

37-690 Bass Choke Replacement
#1

While troubleshooting the no bass amplification issue, I think I found the culprit. The choke #104 is reading 164K ohms. My first thought is replace it with a 2K 5W resistor and increase the 1uf electrolytic, just like you would for a speaker, but that parallel 40K resistor threw me. How do I factor that in?


Attached Files Image(s)
   

RJ Dial
"Radiodial"
Mendocino, CA
#2

https://philcoradio.com/library/download...201942.pdf


This is the parts catalog.

32-7528 choke is 65H, 10mA, 2,250 Ohm inductance.
Find a suitable one.

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

Ah, now where to find one.
I've into this before on smaller sets, I now recall. Hammond makes one that is only rated 8MA, and this 37-690 has two stages of bass amplification, so 8ma may be pushing it.

RJ Dial
"Radiodial"
Mendocino, CA
#4

Yes, I just had to deal with that while repairing the 37-604 Philco. Exactly that value choke was gone. And the current was borderline.
So I used a smaller one with larger current, padding it with a resistor.
However, mine was the DC filter, whereas yours is an audio filter, so you need more precision.
Mine was 32-7569, which is same as yours (maybe different dims) - 65H, 10mA.

I used 154E, 2hich is 20H, 20mA.
There is also 30H 600 Ohm one, 157G. Two in series plus a 1k resistor. Those are small chokes too.

https://www.mouser.com/datasheet/2/177/1...736947.pdf
https://www.mouser.com/c/passive-compone...&m=Hammond

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.
#5

Yeah, I know, Mouser and Digikey don't have "big iron" components. For some reason Philco was messing with the 2250 ohms resistance of this common Philco choke by paralleling that 40K resistor. I wish I was smart enough to understand why. Seems to fine tuning it down to 2.1K?

RJ Dial
"Radiodial"
Mendocino, CA




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
The list of my radio & TV collection!
Peter; I can't say for certain but many North American made radios from that era, the late 1940s onward, had silver m...Arran — 02:06 AM
Philco 39-7C Restore
A little more work today. I got the first IF transformer back together after replacing the wiring going to the 78 tube ...klondike98 — 12:06 AM
Two small radios from France. Restoration and review.
And here they are, the French beauties ready: In summary, the suspicion that radio transmits the national cha...Vlad95 — 10:46 PM
Two small radios from France. Restoration and review.
One is ready for washing, the other for painting: ATTENTION Faint-hearted and heart patients, please d...Vlad95 — 10:36 PM
Two small radios from France. Restoration and review.
Range Switch Block: I thought that mica capacitors of this type died out in the 30s, but no, they just moved ...Vlad95 — 10:29 PM
Two small radios from France. Restoration and review.
Chassis bottom view: Again, like twins, especially in the range switch part. Front panels: And...Vlad95 — 10:25 PM
Two small radios from France. Restoration and review.
Chassis removed, front view: Chassis rear view: It will be enough for the first device to prescribe a bath. Bu...Vlad95 — 10:11 PM
Two small radios from France. Restoration and review.
France Peculiarities of national character. Excelsior-52 threw me off track. It was too far outside my established...Vlad95 — 10:06 PM
Philco 16b no shortwave reception
First let thank everyone who helped ID this radio a few weeks ago! I have replaced all the capacitors and was able to r...Ken D. — 08:07 PM
Philco model 38 code 121 not receiving signal.
Ah yes, the Philco "Green Death" strikes again, someone suspected that cellulose nitrate based insulation migh...Arran — 06:23 PM

[-]
Who's Online
There are currently no members online.

>