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

0.00011 mf caps in bakelite blocks
#1

I'm working on my model 116.  What is the concensus?  Are these 0.00011 mf capacitors replaced during restoration?  On one hand, that value suggests they're mica, which is usually left alone.  But on the other hand, why would these capacitors be potted in tar?  This suggests they are subject to degradation over time.
#2

Inside backelites these are not mica.
Even if they are safe they have likely drifted, they are typically replaced.
#3

I've always used dipped mica 110pF caps here; they are cheap and perfectly suitable for the purpose. I buy at least 20 at a time. These are the caps that look like dark caramel candy.

Pete AI2V
#4

From all of the Philcos that have crossed my bench...and they number in the hundreds, I never bothered to count them...out of those that have 110 pF caps in bakelite block shells, the majority were small paper caps. I have encountered a few that had mica caps encapsulated in the tar, though...but as I said, the majority were paper.

As Pete (AI2V) said, dipped micas are excellent replacements for these. And, yes, I replace them as a matter of course in the Philco sets that use them.

--
Ron Ramirez
Ferdinand IN
#5

[Image: http://www.talonix.com/images/caps4/39pfDSM.jpg]

Looks like this.  Some are larger or smaller, depending 
on the capacitance and working voltage.
#6

I just pulled 4 of those out of bakelite block shells last week and all 4 were paper. I used the dipped micas like in Chuck's photo.
#7

Another question, about the voltage rating on these caps; what were they originally? I would assume 500V micas would be fine?
#8

Yes 500 volt micas will be OK.
#9

Can you double check that? The bakelite block I'm restoring is pn 8035-DG. Philco Service Bulletin No. 289 suggests these capacitors have a working voltage of 1200v.
#10

The maximum voltage these are going to see in the 2nd Detector circuit will be so low as to not be consequential, really.

You can use 1200 VDC caps if you wish. H**l, you can use 12,000 volt caps if you want to. But Codefox is correct, 500 WVDC caps are fine. Even 300 WVDC micas are fine. I use the 500 WVDC micas all of the time to replace these and I haven't had a single failure yet...and I do not expect to since they will only be exposed to somewhere between 0 and 10 volts in this circuit.

--
Ron Ramirez
Ferdinand IN
#11

(12-09-2014, 05:19 PM)Kestas Wrote:  I'm working on my model 116.  What is the concensus?  Are these 0.00011 mf capacitors replaced during restoration?  On one hand, that value suggests they're mica, which is usually left alone.  But on the other hand, why would these capacitors be potted in tar?  This suggests they are subject to degradation over time.

Hi guys, I have run into the same bakelite block in my 38-2 as Kestas.Just a question would 0.0002 @ 630V be to much to use in place of the 0.00011? I have these on hand,but if I have to I will order the correct replacements.
Thanks 
#12

Quote:Just a question would 0.0002 @ 630V be to much to use in place of the 0.00011?
You should stay within a 10 to 20 percent tolerance.
#13

Just ordered up some 110pf caps so i should be good until I tackle THE BEAST my 38-116. After the 38-2, i
would hope things will be easier,still will be a challenge I know. Icon_thumbup but I'm up for it.
#14

Oh...it's just a bunch of wires, glass an metal....nothing a man with a scredriver couldn't take on.
#15

FIRE UP that soldering iron an lemme at it.Wait, I still have to finish the 38-2. Icon_biggrin




Users browsing this thread: 2 Guest(s)
[-]
Recent Posts
trying to identify this wire type
Thanks to all for the feedback. As Arran said, it is probably an older replacement and yes it has a grid cap so I will ...georgetownjohn — 09:32 PM
trying to identify this wire type
It's possible that the red wire, actually a grid cap lead, is a very old replacement, I can't remember seeing a pre 1939...Arran — 09:18 PM
Gilfillan Brothers Car Radio?
Hi everyone,  Special thanks to Joe Rossi for tracking down this obscure radio and thanks to others who took up the hun...Antipodal — 08:15 PM
trying to identify this wire type
Here's one source for your wire of many. Take care and BE HEALTHY! Gary P.S. Can't get the right color you need? I ...GarySP — 06:40 PM
trying to identify this wire type
...and modern wire of the appropriate gauges and insulation V-rating (300V minimum, usually shown right on the wire) is ...morzh — 05:47 PM
1930s Stromberg-Carlson Tombstone Radio need help identifying model number
I have a question about this radio, is there anyone that has access to this radio that has an intact unmolested speaker ...captainclock1988 — 04:28 PM
1930s Stromberg-Carlson Tombstone Radio need help identifying model number
Well what makes me confuse all of those companies is that all three of those companies (Setchell-Carlson, Stromberg-Carl...captainclock1988 — 04:21 PM
trying to identify this wire type
The red wire is rubber covered wire. The others are cotton braid over rubber often in colors or a tracer, also strand...Chas — 02:43 PM
trying to identify this wire type
Greetings Phorum members, Hope you can help me identify this type of wire in the photo I have attached.  I am not sure ...georgetownjohn — 01:53 PM
Philco 60 Squealing
All correct shields must be in place, all tubes correct no subs of any kind. Check any soldered, riveted ground conne...Chas — 01:24 PM

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

>