0.00011 mf caps in bakelite blocks
Posts: 177
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: 15,837
Threads: 554
Joined: Oct 2011
City: Jackson, NJ
Inside backelites these are not mica.
Even if they are safe they have likely drifted, they are typically replaced.
(This post was last modified: 12-09-2014, 05:56 PM by morzh.)
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: 177
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: 15,837
Threads: 554
Joined: Oct 2011
City: Jackson, NJ
Oh...it's just a bunch of wires, glass an metal....nothing a man with a scredriver couldn't take on.
(This post was last modified: 01-20-2015, 11:25 PM by morzh.)
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
|
New Philco Repair Bench
|
Morzh is correct. The repair bench on our website is an archived image of chuck’s original site. He no longer provides s...klondike98 — 05:32 PM |
Made mistake & did not label connection
|
Excellent information. It is all starting to come together now and your explanation really helped since I noticed that ...georgetownjohn — 04:39 PM |
Made mistake & did not label connection
|
Hi John,
I don't have this radio, but I can supply some info:
Based on your pic, pins 7,8 and 1 are used together, go...MrFixr55 — 02:02 PM |
New Philco Repair Bench
|
As far as I know, the Repairbench does not work, and has not been working in a while.
Chuck (we had that campaign looki...morzh — 01:33 PM |
Radio city products 664 schematic request
|
Need a schematic or manual for the 664. The 663 may be similar.daveone23 — 12:38 PM |
New Philco Repair Bench
|
Thanks Gary.dconant — 12:16 PM |
New Philco Repair Bench
|
I tried accessing the site through our library and got the same response. It's reported to our tech gurus. GaryGarySP — 11:50 AM |
New Philco Repair Bench
|
I am sure this is the archive, and not the Chuck's site.morzh — 09:50 PM |
Made mistake & did not label connection
|
It's not like we are good friends with that wire and can tell it from other ptetty identical looking wires.
Why'n't you...morzh — 09:49 PM |
Made mistake & did not label connection
|
I'm not sure why that wire wasn't covered in the video. I'm pretty sure the 6A8 won't work until that pin is grounded. Y...RodB — 09:47 PM |
Who's Online
|
There are currently 4329 online users. [Complete List] » 2 Member(s) | 4327 Guest(s)
|
|
|
|