Mr. C's Capacitance Tester?

As far as I know, Mr Carlson never released (on Patreon) a ”Capacitance Tester” as such. I can only assume that you probably meant to say ”capacitor leakage tester, and if that’s the case, you should look at videos 175, 182, and 185. These videos should have the needed construction PDFs, but they are only available by request. However, there are some other video numbers (I cannot remember now) you could or should watch (concerning this tester) in which MCL also released the construction of a power supply (however, optional), should you want to use 18650 (Li-Ion) battery cells. If not, interested, then you can make/use your own PSU.

Please note that the PCB and the circuit complexity level could be a little ”overwhelming for beginners”.

Or are you thinking of the Foil tester? I feel like any mixing console should either have electrolytics that don’t need special testing or caps that aren’t bad. What warrants a recap for it? If anything a good control cleaning would help the most.

I finally have the spare time to build one myself & have most the parts already… Just setting up the laminator. Trawling through & watching the videos there’s a fair bit going on but i am up for the challenge… I made the Mk1 version & its been useful even though that was few years ago but seems to have developed a fault so i think the newer better version is a good idea. If i can get the imgur image link thing going i will post a few photos…

@peteb2 Some pictures are always welcome and…who knows, might help others with ideas, etc :). Good luck with your build.

Thanks, @ovi4 – yes, that must be it as a leakage tester is far less common than a capacitance tester. The video references are much appreciated – good starting point.

Please note that the PCB and the circuit complexity level could be a little ”overwhelming for beginners”.

Considering I’ve been doing this stuff for 60+ years, I think I should be ok … unless I forget where I put my soldering irons :))

Thanks so much for the detailed reply! – H

@radtekman – thanks for the reply. Wasn’t thinking of the Foil Tester, but that in itself sounds very interesting.

Indeed – only the large Farad or Hi V electrolytics need to be tested and maybe replaced. This board hasn’t been powered up for at least 15 years and it’s 30 years old. I yanked the supply out to Variac ramp up its 120vac source and inline lightbulb test it as well.  I have had them blow up on me before. Smelly, messy business that. LOL. 

As far as the other caps go, there’s always a ton of bypass caps in these things, which can dry out. There were a bunch of caps in the 2000s that were junk.  This is a TASCAM board made in Japan, so it might have some of those, but I’ve not looked at the individual channels yet.  Tops, there will be a few dozen per channel. I will probably test just a couple – if they’re ok, the rest probably will be too. The PSU has only 5 big enough to look at.   The console runs +/- 5 vcd, +/-17 vdc, +48 vdc (phantom power), and 60 vdc <- for which circuit I have no idea. Schematic is unavailable, but do have PCB diagrams. 

Some of the older, tube-based mixers – which are still around – have a lovely, warm quality to them. Those boards, with their tube voltages, and old wax caps can be really gnarly cap-wise. When I worked on these in the past (many years ago), I would just yank all the higher voltage caps that were over 0.1mF and replace them all… easier than goofing around. (FYI – I’m a uni-trained sound engineer and used to design, build and test sound boards and light controllers for a while.)

But since this board is opamp and transistor based most of its caps, as mentioned, are just bypass. The ones in the filters [simple Low, Mid parametric, and High] are all low voltage and rarely need to be replaced.

thanks again for the thoughtful reply – much appreciated!

– H

@peteb2 – hey that’s cool — hope you can post how things go if you can. I will try to do the same … but I keep getting sidetracked with other “life” things … this is now a hobby for me. :))

cheers

– H

@howardp Yes I play with the sound side of things too as far as “live sound” things go. I have a small setup with an 8 channel mixer and the rest. A tube console sounds like fun, can’t say I have looked into those. Currently my collection is radios and scopes with other odds and ends. Being low voltage would make things much easier as long as the ESR is still good on the electrolytics. Let us know how it goes.