Reforming Old Electrolytic Capacitors

WEBVTT
Kind: captions
Language: en

00:00:24.450
hi and welcome back if you saw my last
00:00:29.220 00:00:29.230 video you know I was in the process of
00:00:32.040 00:00:32.050 selling my soul our capacitor tester I
00:00:34.320 00:00:34.330 did the comparison between it and the
00:00:36.180 00:00:36.190 two Heath kits and linked my eBay sales
00:00:41.939 00:00:41.949 thing to the video and within six hours
00:00:45.570 00:00:45.580 of putting it on eBay it was gone it
00:00:47.549 00:00:47.559 just disappeared
00:00:48.840 00:00:48.850 so that's sold and it sure is there's
00:00:52.200 00:00:52.210 ticks and new hampshire in the
00:00:53.549 00:00:53.559 springtime friend of mine calls me up
00:00:55.530 00:00:55.540 this morning and says do you have any
00:00:57.799 00:00:57.809 250 microfarad 304 well I sure do I have
00:01:05.790 00:01:05.800 a bunch of capacitors in my junk box and
00:01:08.370 00:01:08.380 this one here actually is a 250 plus 20
00:01:11.880 00:01:11.890 plus 20 at 350 working volts but it's
00:01:16.680 00:01:16.690 probably been in my junk box for some 30
00:01:19.440 00:01:19.450 odd years just sitting there doing
00:01:21.990 00:01:22.000 nothing and it's not wise to take these
00:01:25.139 00:01:25.149 capacitors and connect them to the full
00:01:28.260 00:01:28.270 working voltage right away
00:01:29.850 00:01:29.860 when the capacitor has been sitting that
00:01:31.680 00:01:31.690 long the electrolyte is usually settled
00:01:34.650 00:01:34.660 out and you want to reform these things
00:01:36.900 00:01:36.910 before you even try to put high voltage
00:01:38.969 00:01:38.979 on them my soul our capacitor tester
00:01:41.760 00:01:41.770 which is now gone did that very easily
00:01:44.070 00:01:44.080 you just cranked up the voltage and it
00:01:46.499 00:01:46.509 had a built-in milliamp meter now I
00:01:48.779 00:01:48.789 could have gone to the problems or the
00:01:50.580 00:01:50.590 trouble of taking my old triplet over
00:01:54.059 00:01:54.069 here and hooking that up in series with
00:01:56.490 00:01:56.500 my high voltage power supply up there
00:01:58.889 00:01:58.899 and running test leads and test clips
00:02:01.440 00:02:01.450 each and every place a little bit of
00:02:03.359 00:02:03.369 table but I decided that since the
00:02:06.660 00:02:06.670 solaiyur was gone I was going to put
00:02:08.999 00:02:09.009 something like this together and this is
00:02:11.550 00:02:11.560 just a BNC in for the DC a BNC out for
00:02:16.979 00:02:16.989 the capacitor and a 5 milliampere motor
00:02:20.420 00:02:20.430 motor yeah meter movement and I put a
00:02:24.360 00:02:24.370 homemade shunt across there so that
00:02:26.280 00:02:26.290 it'll handle 50 milli amperes as well
00:02:28.619 00:02:28.629 because you don't want to start out on 5
00:02:30.270 00:02:30.280 milliamps in case the capacitors shorted
00:02:32.580 00:02:32.590 or
00:02:33.160 00:02:33.170 from the get-go and again I could have
00:02:38.320 00:02:38.330 used just the standard triplet but this
00:02:40.150 00:02:40.160 makes it nice and neat and easy so I'm
00:02:42.490 00:02:42.500 back in business here and we'll take a
00:02:43.990 00:02:44.000 quick peek at once it's stated this
00:02:45.880 00:02:45.890 thing couldn't be more dead simple we've
00:02:49.090 00:02:49.100 got power in through the milliamp meter
00:02:51.790 00:02:51.800 and back out to the capacitor and when
00:02:54.640 00:02:54.650 we want the 50 milliampere scale we
00:02:57.490 00:02:57.500 should switch in this shunt this
00:02:59.680 00:02:59.690 homemade shunt and this is nothing but a
00:03:01.570 00:03:01.580 length of iron wire that I had laying
00:03:03.970 00:03:03.980 around that works out to about 1 ohm per
00:03:07.210 00:03:07.220 foot and I needed a point 6 ohm shunt
00:03:10.780 00:03:10.790 resistor to make this meter work at 50
00:03:13.870 00:03:13.880 milli amperes to do a times 10 on the
00:03:16.300 00:03:16.310 scale we won't bother going to the math
00:03:18.670 00:03:18.680 there's a hundred websites out there to
00:03:20.560 00:03:20.570 show you how to figure out the
00:03:22.090 00:03:22.100 resistance of your meter and no you
00:03:23.830 00:03:23.840 can't do it with an old meter you have
00:03:25.630 00:03:25.640 to do it with a couple of resistors and
00:03:27.610 00:03:27.620 measuring the current through it you can
00:03:29.500 00:03:29.510 work out the resistance of the meter
00:03:31.210 00:03:31.220 from that you can work out the
00:03:33.280 00:03:33.290 resistance needed to make your times 10
00:03:35.320 00:03:35.330 shunt that the it's dead simple as a
00:03:37.569 00:03:37.579 hundred people have done it we won't
00:03:39.039 00:03:39.049 bother just wanted to show you how
00:03:40.900 00:03:40.910 stupid simple this was inside so what do
00:03:43.690 00:03:43.700 we do with this thing well we hook up a
00:03:45.580 00:03:45.590 BNC cable to the DC N and up here on our
00:03:51.270 00:03:51.280 Keith get high voltage supply we have a
00:03:54.160 00:03:54.170 BNC adapter over here we plug that in
00:03:58.300 00:03:58.310 I'm going to turn the voltage all the
00:04:00.490 00:04:00.500 way down to start with then we come back
00:04:05.620 00:04:05.630 down here and I've got a BNC cable it
00:04:12.640 00:04:12.650 plugs in on the capacitor side got a
00:04:17.740 00:04:17.750 couple of clips on the end of it wrong
00:04:22.090 00:04:22.100 capacitor now this one that's - and 250
00:04:27.520 00:04:27.530 volt 250 micro farad's there so I'm
00:04:30.010 00:04:30.020 going to clip this here we start on the
00:04:33.130 00:04:33.140 50 milli ampere scale just in case
00:04:35.320 00:04:35.330 everything goes to hell clip this on
00:04:40.060 00:04:40.070 here and I'm going to start slowly
00:04:43.450 00:04:43.460 turning the voltage up let's try to get
00:04:45.760 00:04:45.770 this in the shot
00:04:47.550 00:04:47.560 start bringing the voltage up see what
00:04:50.020 00:04:50.030 happens you can see the current starts
00:04:51.730 00:04:51.740 to rise and it's falling off pretty
00:04:53.410 00:04:53.420 quickly so this looks like a fairly
00:04:54.910 00:04:54.920 decent cap I'm going to flip over here
00:04:57.520 00:04:57.530 in the 5 milliampere scale and slowly
00:05:01.450 00:05:01.460 start working this thing up and you can
00:05:04.420 00:05:04.430 see that plots a little noisy up there
00:05:06.460 00:05:06.470 so I'm going to kick this back down but
00:05:09.610 00:05:09.620 it looks like we're staying down in the
00:05:12.520 00:05:12.530 1 milliampere range
00:05:14.730 00:05:14.740 there's a hundred 150 and it's dropping
00:05:19.510 00:05:19.520 off pretty quick it looks like this caps
00:05:21.340 00:05:21.350 in fairly good shape there's 200 it's
00:05:29.080 00:05:29.090 starting to fall a little bit slower now
00:05:31.480 00:05:31.490 at 250 and it's sitting right up around
00:05:33.820 00:05:33.830 5 milli amperes and you can see it's
00:05:38.410 00:05:38.420 falling off so the capacitor is doing
00:05:41.020 00:05:41.030 alright the current in it is fairly low
00:05:43.360 00:05:43.370 you want to keep it down to a couple of
00:05:45.670 00:05:45.680 milli amperes during this process you
00:05:48.010 00:05:48.020 don't stress the capacitor so I'm going
00:05:52.780 00:05:52.790 to let that sit right at that level for
00:05:54.880 00:05:54.890 a few minutes and now it's falling off
00:05:59.200 00:05:59.210 let's go back up here I'm going to bring
00:06:02.830 00:06:02.840 it up to 300 volts and again it's
00:06:07.870 00:06:07.880 falling off no it's jittering around a
00:06:10.180 00:06:10.190 little bit not settle down or under 5
00:06:13.870 00:06:13.880 milliamps I'll let that sit and lay our
00:06:17.380 00:06:17.390 cap has been reforming for about an hour
00:06:19.690 00:06:19.700 and I've been keeping an eye on it
00:06:22.660 00:06:22.670 occasionally sneaking the voltage up and
00:06:24.880 00:06:24.890 keeping it around 1 milliampere or less
00:06:28.270 00:06:28.280 not to stress the cap and now that we're
00:06:31.030 00:06:31.040 up to the working voltage of 350 we're
00:06:33.700 00:06:33.710 down to about a hundred micro amperes so
00:06:36.460 00:06:36.470 I think this capacitor is going to be ok
00:06:38.530 00:06:38.540 for his little science project he's
00:06:40.240 00:06:40.250 going to build the last step is going to
00:06:42.460 00:06:42.470 be disconnect the cap and thoroughly
00:06:45.190 00:06:45.200 discharge it and then I'll use my ESR
00:06:47.620 00:06:47.630 meter to see how good the cap really is
00:06:51.420 00:06:51.430 okay so we've discharged the cap and
00:06:54.280 00:06:54.290 we've let it sit here for a couple of
00:06:56.590 00:06:56.600 minutes with a shorting bar or shorting
00:06:59.800 00:06:59.810 jumper
00:07:00.490 00:07:00.500 and the reason I've done that is you'll
00:07:03.100 00:07:03.110 find these capacitors if you discharge
00:07:05.290 00:07:05.300 them with a resistor or even a
00:07:06.670 00:07:06.680 screwdriver and you come back a couple
00:07:08.740 00:07:08.750 minutes later you'll get another spark
00:07:10.420 00:07:10.430 out of them you come back a few minutes
00:07:11.860 00:07:11.870 after that you'll get another spark out
00:07:13.540 00:07:13.550 of them it's a known effect with big
00:07:15.670 00:07:15.680 electrolytic that they will rebuild some
00:07:18.160 00:07:18.170 of the charge and that's why you see
00:07:20.380 00:07:20.390 these great big oil filled high-voltage
00:07:22.300 00:07:22.310 capacitors they always have a shorting
00:07:25.030 00:07:25.040 wire across them because if they've been
00:07:27.970 00:07:27.980 charged and yet they're disconnected
00:07:30.250 00:07:30.260 they can build up a good portion of that
00:07:32.710 00:07:32.720 charge again it won't have as big a
00:07:34.750 00:07:34.760 current hit but they can build up to
00:07:37.510 00:07:37.520 many thousands of volts and some of
00:07:39.820 00:07:39.830 those big capacitors so you discharge
00:07:42.940 00:07:42.950 them for a period of time to make sure
00:07:44.500 00:07:44.510 it's down and I'll turn on my little
00:07:46.690 00:07:46.700 Chinese esra meter here got this guy off
00:07:50.350 00:07:50.360 eBay and it works extremely well you can
00:07:53.800 00:07:53.810 test the equivalent series resistors
00:07:56.220 00:07:56.230 resistance of a capacitor in circuit
00:07:58.630 00:07:58.640 with this because it uses an extremely
00:08:01.540 00:08:01.550 low voltage that won't turn on the
00:08:04.180 00:08:04.190 transistors and diodes in the circuit
00:08:06.010 00:08:06.020 and it's zeroed so I'm going to
00:08:08.860 00:08:08.870 disconnect my short and I'm expecting
00:08:11.770 00:08:11.780 about less than a tenth of an ohm there
00:08:14.710 00:08:14.720 should be less than a tenth of an ohm
00:08:16.210 00:08:16.220 here for this sized capacitor if it's
00:08:19.420 00:08:19.430 any good and it's very good that's point
00:08:24.219 00:08:24.229 zero six now our brand-new modern
00:08:26.469 00:08:26.479 capacitor can you see that in the point
00:08:29.890 00:08:29.900 zero 6 ohms a brand-new modern capacitor
00:08:33.790 00:08:33.800 might get down to point zero four or
00:08:36.130 00:08:36.140 point zero three ohms but for something
00:08:39.010 00:08:39.020 this age that's been sitting in the junk
00:08:40.959 00:08:40.969 box forever that's a pretty decent cap
00:08:43.980 00:08:43.990 so now that we've reformed the
00:08:46.870 00:08:46.880 electrolytic capacitor will hand this
00:08:49.450 00:08:49.460 off to my buddy for his science project
00:08:51.100 00:08:51.110 maybe I had to charge it up and hand it
00:08:53.230 00:08:53.240 off no I won't do that
00:08:54.550 00:08:54.560 and he'll be able to build his project
00:08:57.190 00:08:57.200 and he'll be a happy camper so I'm going
00:08:59.290 00:08:59.300 to give him a call and for now that's it
00:09:01.420 00:09:01.430 we'll see you again okay okay okay I
00:09:03.880 00:09:03.890 heard all of you out there yelling and
00:09:06.220 00:09:06.230 hollering at me why didn't you put a
00:09:08.710 00:09:08.720 discharge function on it so I did now we
00:09:12.880 00:09:12.890 have operate
00:09:14.450 00:09:14.460 and discharge so I won't have to
00:09:16.700 00:09:16.710 disconnect the capacitor to discharge it
00:09:18.889 00:09:18.899 all I have to do is flip the switch that
00:09:22.090 00:09:22.100 is a double pole double throw two amps
00:09:26.630 00:09:26.640 switch with both contacts or both poles
00:09:30.139 00:09:30.149 parallel so that it's four amps worth
00:09:32.750 00:09:32.760 going through a 5,000 ohm resistor and
00:09:36.280 00:09:36.290 since my power supply will only produce
00:09:38.810 00:09:38.820 about 400 volts that's about 80 million
00:09:41.540 00:09:41.550 peers without a handle left with ease so
00:09:44.620 00:09:44.630 there you have it now we have an operate
00:09:47.449 00:09:47.459 discharge switch as well as the current
00:09:49.519 00:09:49.529 switch that wills that's it this is
00:09:52.160 00:09:52.170 really the end this time take care bye
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