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

Micamold Capacitor Value and Type ???
#1

Can one of the knowledgeable members help me identify the type and value of a Micamold cap? Illustration of the cap follows. This item is from a Philco 41-290, first IF can (item 32 – p/n 32-3482). Cap is about 3/4" x 3/4" in size.






Note from site admin: Sorry, but the photos which were attached to this post are no longer available.
#2

Ok I'll take a stab at it. The top red dot = 2 (20%) Bottom dots = 300. 300pf@ 20%. If it's on the plate side of the coil go with a 500v job ( common).
Good Luck
Terry
#3

Thanks for your reply. If the bottom dots are the cap value, I think it should be 30 X 100 = 3000pf.
First digit (orange) =3, second digit (black) = 0, and multiplier (red) = 2 or 100. At 3000 pf, it is unclear to me if this is a encapsulated paper cap or a mica.

Any thoughts will be appreciated as the schematic does not detail the value or type for this cap.

Thanks
#4

According to this website, TFB, you are correct.

But I wonder about 3000 pF in that circuit?

Very interesting. The primary of that IF transformer is slug tuned, as are many 1940-42 Philco IFs, and it uses that mica cap in parallel with the primary winding.

Being a Micamold cap, it's hard to say if it really is mica or not. Some Micamold caps have a paper cap encapsulated in that package that looks like a mica cap. The Micamolds are beginning to fail at a rising rate, also.

I would replace it with a new mica cap or an NP0 ceramic to avoid drift while in operation.

--
Ron Ramirez
Ferdinand IN
#5

Don't know but .003 seems a bit large.
Terry
#6

I just happened to look at a schematic for a 41-295 (fairly similar unit) and it details this cap at 3000pf. I also thought this was somewhat large and was the reason I posted the inquiry. At 3000pf (.003mf), it's likely to be paper and I'll replace it while I have the IF can disassembled.

Thanks to all for you assistance.
#7

Good catch, TFB. Thank you for enlightening us.

--
Ron Ramirez
Ferdinand IN




Users browsing this thread:
[-]
Recent Posts
Philco 91 Speaker Replacement
The spider is glued on the cone and so is the voice coil. I think you can use a cotton swab dipped in acetone and carefu...RodB — 02:42 PM
Restoring Philco 37-604C
Yes I saw that. If I knew, I'd probably try to arrange for getting it myself. But I have just got one. Which does not m...morzh — 01:44 PM
Philco 38-2 Automatic Tuning
When you push the lever, you are supposed to rotate the disk to the desired station. Then the magnetic tuning will acqu...morzh — 01:42 PM
Philco 38-2 Automatic Tuning
I figure out the muting from another picture that helped. Now I need to know how the automatic tuning works. When I push...dconant — 12:11 PM
Philco 91 Speaker Replacement
How would I go about removing the spider from the cone?dconant — 12:04 PM
Philco 38-2 Automatic Tuning
Hello, I am having trouble getting my automatic tuning to stay unmuted. If I play with the tuning handle I can get it to...dconant — 10:51 AM
Does anyone make photofinish replacements?
Here’s the link to the DIY photofinish section of our site: klondike98 — 09:46 AM
Delco car radio Peko vibrator converstion issues
Hi Richard, Thx for posting the schematic.  As I remember as a kid, these were great performers for the time, likely...MrFixr55 — 08:56 AM
Delco car radio Peko vibrator converstion issues
hello mr Fixr, The Electro  Powersupply that I am powering the radio with has a huge choke plus a 10,000ufd electrolyti...radiorich — 10:58 PM
Delco car radio Peko vibrator converstion issues
How about putting a choke in the power supply? The big cap was likely an attempt to stabilize the DC. Kids who cre...MrFixr55 — 09:19 PM

[-]
Who's Online
There are currently 2842 online users. [Complete List]
» 1 Member(s) | 2841 Guest(s)
Avatar

>