#2091

[@mikesradiorepair]

You forgot to show filling up the magic smoke reservoir. It can't possibly work correctly if the correct amount of magic smoke wasn't put back in. 🙂

[@IMSAIGuy]

I can't give away all my secrets!

[@karltest1314]

Happy New Year. Look ok Ali for "hollow desoldering needles" - stops you killing tracks on the larger loose fitting holes

[@TomSherwood-z5l]

I have to be satisfied with an LC-102 LC tester but it seems to exceed my needs for accuracy. I got a cal lab Genrad cap that is rated at 0,01 plus or minus 0,25% or 25 pf? and the Sencore reads all zeroes at the end. I once had a 100pf SM that I hand selected with a lab grade tester for being on the money but misplaced it.

[@pault6533]

Perhaps replace the burnt traces with fuses instead of bodge wires. What if this happens again?

[@orion310591RS]

What values of fuses you would put? There is a chance to trigger fuse when capacitor is charging for first time I think.

[@pault6533]

@ thin wires of similar cross section area to the PCB trace.

[@TomSherwood-z5l]

Yea what are the chances it will happen in his lifetime with new caps though? The Nichicon caps ought to last decades.

[@silverXnoise]

Today we learned: fuses are just wires.

[@MrBanzoid]

It's always the capacitors!

[@Mr.Leeroy]

I know you got that fairy tale Cali local store, but why not use global distributor like IDK mouser (their "4 Pin Aluminum Electrolytic Capacitors - Snap In" comes up un seach just fine). These ECaps are not rare at all, even sold on Ali as well.

[@IMSAIGuy]

I got these from Digikey. what is the part number, I must have missed it.

[@Mr.Leeroy]

@@IMSAIGuy on Digikey -try- "Lead spacing = 22.5mm" filter in ECap section. *_UPD:_* no, you missed it completely, there is Package-Case filter = "Radial Can Snap-In 4 Lead". Mouser has in stock: 382LX223M063N082 (40d80L beast) and ALC10C223ED035 40dx40L Kemet I'd go for (there is a typo, it's a 35VDC cap which probably got rebranded to 40V having same sizecode 'ED' in a newer version of ALC10 Series datasheet)

[@IMSAIGuy]

@@Mr.Leeroy ok, sure enough. I think i had the lead spacing to 10mm while doing the first searches and forgot I had that set when looking at the 4 pin versions.

[@TomSherwood-z5l]

I got a Q for you. Is it possible to fabricate a low C reference cap of accurate value with formulas? For instance say you have some thin glass of known thickness measured with a micrometer and known dielectric constant. Can you place metal plates on either side of exact dimensions and then use the calculations to determine the exact value? Same with an air wound inductor. Known exact wire size, versus dimensions, say close wound. As for resistor standards. Resistance wire with precise resistance per foot is available, so it should be possble to make a low resistance value pretty precisely? At least at a known room temperature?

[@IMSAIGuy]

Yes. There are equations. First order. The real world will introduce some small errors.

[@henrikstenlund5385]

Far more reliable are tantalum caps than electrolytics. However, they are not available in high values and become expensive at fairly high values. Solid electrolyte caps are also extremely reliable but lack high values too.

[@simontay4851]

Tantalum caps are not reliable. If they go short (and they do), they explode and set on fire. Not good.

[@analog_guy]

@@simontay4851 Military reliability guidelines specify a minimum resistance be used in series with tantalum capacitors to avoid sudden failures when initially charged at turn-on. One reference from RADC says 3 ohms per volt. I have seen other MIL references with guidelines based on capacitor value, if I remember correctly, but I no longer recall the specific documents.

[@henrikstenlund5385]

@@simontay4851 They are most reliable and run for decades without problem. Only if the voltage polarity becomes incorrect, it will destroy it. turning to flames is areal thing and everyone can test it. This means, the caps must be diode protected and fused

[@mikesradiorepair]

@@henrikstenlund5385 Tell that to the dozens of dead shorted dipped tantalum capacitors I replace every year. Some don't even exist anymore. Nothing but two leads sticking out of the PCB. The caps have exploded into a 100 pieces. At best I would say tantalum capacitors are ever so slightly more reliable than decent quality wet aluminum electrolytic capacitors.

[@henrikstenlund5385]

@@mikesradiorepair I have been in the business for decades. There is always a reason for a Tantalum to die. It may be that some pirate parts may be the culprits in your cases. Also the reasons I mentioned above. If the voltages are too close to the margins, they are in the risk. If you put a 15V cap to 16 V, it may break down. The margin must be much bigger, like a 25V or 35 V type. Bad design

[@felixcat4346]

You make the silliest videos