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

Re-building backelite capacitors
#5

morzh Wrote:Today finished re-stuffing all the bakelites.

When I replaced the last one, number 8, the one with 250 Ohm resistor and 0.05uF cap, all started sounding quite a bit better.

The cap was giving me a weird reading - it would start with 0.06uF on on polarity, then, if re-polarized, would read 0.370uF and when put back to the first polarity, read 0.13uF. If disconnected from the meter and given time to discharge, it would fall back to 0.06uF.

I had two caps acting in this way out of five of them. I am not sure of the electrical mechanism behind it, and it is not important. Just interesting.

This is called leakage. Probably all of the caps you replaced were at least somewhat leaky. When the caps are as bad as the ones you have described above, you can actually measure the leakage on an analogue vtvm or vom on the highest ohms scale. On the paper caps that are not as bad, you will still be able to measure the leakage on a good cap checker, like a Sprague Tel-Ohmike and others.

Ed


Messages In This Thread
Re-building backelite capacitors - by morzh - 11-18-2011, 10:34 PM
Re: Re-building backelite capacitors - by Arran - 11-19-2011, 01:33 AM
Re: Re-building backelite capacitors - by morzh - 11-19-2011, 03:42 PM
Re: Re-building backelite capacitors - by morzh - 11-19-2011, 11:09 PM
Re: Re-building backelite capacitors - by etech - 11-20-2011, 11:44 AM
Re: Re-building backelite capacitors - by morzh - 11-20-2011, 08:17 PM



Users browsing this thread: 2 Guest(s)
[-]
Recent Posts
Philco 46-420 Code 121 Reception issues
Welcome Eric, I agree with Bob and far as the two main electrolytic filter capacitors did you change them yourself or w...radiorich — 11:43 PM
Philco 46-420 Code 121 Reception issues
You mentioned the Philco manual and going through the check points...just to be sure we're on the same page here's the m...klondike98 — 08:13 PM
Philco 42-1008 conversion kit
Interesting. I haven't seen that before.klondike98 — 07:02 PM
12' Philco
Yes I had looked for it on the web as well some time back and could not find it. I was glad to see it turned up in Ron'...klondike98 — 06:59 PM
Shadow Meter Bulb
Now if you had a set with a tuning light then the bulb type is important to the circuit, some sets used those prior to t...Arran — 04:58 PM
Shadow Meter Bulb
Ok. Thanks for the correction.RossH — 03:09 PM
Model 28L
For 28 you will probably need to buy a Hammond 125CSE. Or any of the series of the power you need, with SE suffix. Then ...morzh — 02:09 PM
37-60 revision 6
I am restoring a Philco 37-60 and it shows run 6 they removed the ground from G3 of the 6K7G and put the G3 to -2.5v for...bobbyd1200 — 01:01 PM
Shadow Meter Bulb
Mike is correct on the bulb connection, two separate circuits. I found that by rotating the bulb and sliding it forward ...RodB — 12:19 PM
Hickok AC51 tube tester
Cleaned ann contacts, switches and sockets, works great now.martinj — 11:32 AM

[-]
Who's Online
There are currently 6128 online users. [Complete List]
» 5 Member(s) | 6123 Guest(s)
AvatarAvatarAvatarAvatar
Avatar

>