0.00011 mf caps in bakelite blocks
Posts: 178
Threads: 19
Joined: Feb 2014
City: The Motor City,Detroit MI
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.
Posts: 18,427
Threads: 622
Joined: Oct 2011
City: Jackson
State, Province, Country: NJ
Inside backelites these are not mica.
Even if they are safe they have likely drifted, they are typically replaced.
Posts: 201
Threads: 26
Joined: Dec 2005
City: Morris Plains, NJ
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
Posts: 13,776
Threads: 580
Joined: Sep 2005
City: Ferdinand
State, Province, Country: Indiana
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
Posts: 1,703
Threads: 55
Joined: Sep 2005
City: Evanston, IL
[Image: http://www.talonix.com/images/caps4/39pfDSM.jpg]
Looks like this. Some are larger or smaller, depending
on the capacitance and working voltage.
Posts: 344
Threads: 38
Joined: Jun 2011
City: Tustin
State, Province, Country: California
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.
Posts: 79
Threads: 13
Joined: Feb 2014
City: Bristol, RI
Another question, about the voltage rating on these caps; what were they originally? I would assume 500V micas would be fine?
Posts: 2,128
Threads: 18
Joined: Oct 2008
City: Merrick, Long Island, NY
Yes 500 volt micas will be OK.
Posts: 178
Threads: 19
Joined: Feb 2014
City: The Motor City,Detroit MI
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.
Posts: 13,776
Threads: 580
Joined: Sep 2005
City: Ferdinand
State, Province, Country: Indiana
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
Posts: 40
Threads: 6
Joined: Aug 2014
City: Lakewood, Ca 90713
(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
Posts: 736
Threads: 26
Joined: Jun 2013
City: Hayward, California
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.
Posts: 40
Threads: 6
Joined: Aug 2014
City: Lakewood, Ca 90713
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.  but I'm up for it.
Posts: 18,427
Threads: 622
Joined: Oct 2011
City: Jackson
State, Province, Country: NJ
Oh...it's just a bunch of wires, glass an metal....nothing a man with a scredriver couldn't take on.
Posts: 40
Threads: 6
Joined: Aug 2014
City: Lakewood, Ca 90713
FIRE UP that soldering iron an lemme at it.Wait, I still have to finish the 38-2.
Users browsing this thread: 1 Guest(s)
|
|
Recent Posts
|
|
Philco P45-6365 Universal Transformer Instruction Manual
|
| Can anyone guide me to where this may be found?GRG — 03:00 PM |
|
54C Complete Teardown/Rebuild
|
| I don't think that I have encountered a 12Z3 before, curious how it uses one of those but includes a #43, which is a 25 ...Arran — 02:17 PM |
|
HiFi (Chifi) tube amp build - but my own design.
|
| It's the other forum. I'm also in DIY, but mostly read there. Honestly, I kinda jumped into this without much thought to...TV MAN — 10:43 AM |
|
Philco 71 Code 125
|
| Hello,
I am in need of a schematic for this radio. Mine has the three separate circular tube shields and a shadow me...dconant — 08:06 AM |
|
Stromberg Carlson 1500 Squeal
|
| And life just keeps getting more complicated.dconant — 07:57 AM |
|
54C Complete Teardown/Rebuild
|
| Hello Roy,
here is this one
sincerely Richardradiorich — 12:45 AM |
|
54C Complete Teardown/Rebuild
|
| Richard,
Had grabbed it already but thank you just the same. I find myself wanting to find some way to block out the...glyphmon — 12:03 AM |
|
54C Complete Teardown/Rebuild
|
| Hello roy,
here is a link to the schematic .
Sincerely Richardradiorich — 11:54 PM |
|
54C Complete Teardown/Rebuild
|
| Richard,
The Silvertone 2014 also is a transformerless set, so I am incorporating a 1:1 600 ohm audio isolation transfo...glyphmon — 11:37 PM |
|
Preliminary work on wife's Silvertone 2014
|
| Did an alignment today which was interesting. IF alignment went great, almost all was already spot-on. Adjusting on th...glyphmon — 11:35 PM |
|
Who's Online
|
There are currently 1942 online users. [Complete List] » 2 Member(s) | 1940 Guest(s)
|
|
|
|

|