I am attempting my first re-capping job on a 1948 Philco 48-200 radio.
I have come across what I think is a melted capacitor (brown tubular item in center of photo). However, (and I am new so I am not sure), I cannot find this on my schematic of the radio, and I do not know what the capactance is for this item. it attaches at pin 6 to the 50L6GT tube and pin 5 of the 14A7 tube. it is in parellel with a resistor but being such a newbie, I don't know what it's resistance is.
If someone could help me out with this, I would appreciate it.
Thank you.
Just added new phot of underside of mystery capacitor.
(This post was last modified: 03-05-2012, 08:08 AM by winkydink.)
(03-05-2012, 07:24 AM)winkydink Wrote: I am attempting my first re-capping job on a 1948 Philco 48-200 radio.
I have come across what I think is a melted capacitor (brown tubular item in center of photo). However, (and I am new so I am not sure), I cannot find this on my schematic of the radio, and I do not know what the capactance is for this item. it attaches at pin 6 to the 50L6GT tube and pin 5 of the 14A7 tube. it is in parellel with a resistor but being such a newbie, I don't know what it's resistance is.
If someone could help me out with this, I would appreciate it.
Thank you.
Just added new phot of underside of mystery capacitor.
Hi,
The cap. is C202, 220pf, in parallel with the 470K resistor. Pin 6 of the 50L6 is a B- tie point on the tube socket and not an active tube pin. Just use a standard 630V cap. and you'll be fine. Be sure to check all other components. John
(03-05-2012, 07:24 AM)winkydink Wrote: I am attempting my first re-capping job on a 1948 Philco 48-200 radio.
I have come across what I think is a melted capacitor (brown tubular item in center of photo). However, (and I am new so I am not sure), I cannot find this on my schematic of the radio, and I do not know what the capactance is for this item. it attaches at pin 6 to the 50L6GT tube and pin 5 of the 14A7 tube. it is in parellel with a resistor but being such a newbie, I don't know what it's resistance is.
If someone could help me out with this, I would appreciate it.
Thank you.
Just added new phot of underside of mystery capacitor.
Hi,
The cap. is C202, 220pf, in parallel with the 470K resistor. Pin 6 of the 50L6 is a B- tie point on the tube socket and not an active tube pin. Just use a standard 630V cap. and you'll be fine. Be sure to check all other components. John
Thanks, That is exactly what my father-in-law told me too. I guess I will need to pick one of these up at Radio Shack.
(03-05-2012, 11:33 AM)John R Wrote: Hi,
The cap. is C202, 220pf, in parallel with the 470K resistor. Pin 6 of the 50L6 is a B- tie point on the tube socket and not an active tube pin. Just use a standard 630V cap. and you'll be fine. Be sure to check all other components. John
Thanks, That is exactly what my father-in-law told me too. I guess I will need to pick one of these up at Radio Shack.
Well I tried Radio Shack but they only had 100 pf capacitors. I just received a big order of capacitors and resistors from "Just Radios" but did not order this type of cap. Any suggestions from anyone where I can buy just 1 of these caps and not have to pay alot for shipping.
Also a link to the proper capacitor on the vendors page would also be appreciated. I have looked at Antique Electronic supply's web site but could only find ceramic caps at 220 pf, no tubular.
(03-05-2012, 07:24 AM)winkydink Wrote: I am attempting my first re-capping job on a 1948 Philco 48-200 radio.
I have come across what I think is a melted capacitor (brown tubular item in center of photo). However, (and I am new so I am not sure), I cannot find this on my schematic of the radio, and I do not know what the capactance is for this item. it attaches at pin 6 to the 50L6GT tube and pin 5 of the 14A7 tube. it is in parellel with a resistor but being such a newbie, I don't know what it's resistance is.
If someone could help me out with this, I would appreciate it.
Thank you.
Just added new phot of underside of mystery capacitor.
Hi,
The cap. is C202, 220pf, in parallel with the 470K resistor. Pin 6 of the 50L6 is a B- tie point on the tube socket and not an active tube pin. Just use a standard 630V cap. and you'll be fine. Be sure to check all other components. John
Hi, agree with John except the resistor in your set R203 reads 430K (yellow=4, orange=3, yellow=4 [43 plus 4 zeros]) not the 470K that the schematic calls for.
I'm not sure if those dogbone ceramic capacitors are still manufactured, but as Codefox said, you can use a ceramic disc cap to replace it. Two 100 pF ceramics in parallel should work fine.
Several suppliers of capacitors are listed in the Resources pages of my website. You may not find the exact same type (in this case, "dogbone" ceramics), but you can almost always find a substitute.
Hi, agree with John except the resistor in your set R203 reads 430K (yellow=4, orange=3, yellow=4 [43 plus 4 zeros]) not the 470K that the schematic calls for.
I believe that the resistor is 470K. The second band is violet, I think. If you look at the resistor above the capacitor, you will see that it clearly has an orange band. Going by that, I think the resistor below the capacitor is Yellow, violet, yellow.
Steve, I'm referring to the resistor which is between the two caps. It clearly has yellow orange yellow which is 430K. The schematic calls for 470K, yellow violet yellow. I don't see a yellow violet yellow cap in the picture. PL
(03-07-2012, 11:53 AM)planigan Wrote: Steve, I'm referring to the resistor which is between the two caps. It clearly has yellow orange yellow which is 430K. The schematic calls for 470K, yellow violet yellow. I don't see a yellow violet yellow cap in the picture. PL
Im just saying, the second band doesn't look very orange compared to the orange on the resistor just above it.
The resistor that is in parallel with the dogbone ceramic 220 pF capacitor is 470K (yellow - violet - yellow).
Look closely. That is a very light violet...almost dark pink...but definitely violet. I've seen old 470K resistors with very light violet bands like this before.
Now if you look above the 220 pF dogbone cap, there is a resistor with an orange band and a silver band; can't make out the other bands. The orange is definitely a different color than the light violet of the 470K resistor.
430K isn't a standard value, and wasn't back then, either...
Gentleman, I bow to the numbers. My eyes must be growing weaker that I cant see that as violet. The schematic calls for it to be violet and as pointed out 430K would be a wild duck number. PL
Here is another questions for those out in radio land.
It seems to me that in many cases, the radio I am working on, and the schematic don't agree.
(A) For example the schematic may say that a capacitor attaches to pin 2 but on the radio it is pin 3.
(B) The schematic says that the electrolytic caps should be 20 25 30, but the cap in the radio is 10 20 30.
I know in some case for (A) one of the leads may attach to B- so it may be that there are many options for this, and in (B) case, the radio has been repaired so they may have substituted.
My question is, when I encounter a difference between the radio and the schematic which should I use. I don't have enough or ANY real electronic experience to make an educated guess about differences in pin numbers. My gut tells me, to put it back together the way the radio is presently wired.
Any thoughts ?
(This post was last modified: 03-08-2012, 10:58 AM by winkydink.)