Non-Switching SIFT Project

Not wishing to come across as thick, but what is an SIFT?

@brian-wood It is a Patreon project that help you find the outside foil side of a capacitors.

@brian-wood A device that helps you identify the foil side (leg) of a non-polarised capacitor. It comes in 3 variants. One is just an electronic switcher device and needs to be used in conjunction with an oscilloscope (video 28) as well as on YouTube (in some form). The second variant is the so-called “non-switching” version which is another device (in fact an addon) that works in conjunction with variant 1 to eliminate the need to use an oscilloscope (See Video 47). The third variant is basically the previous 2 variants together in one single/compact unit that does pretty much the same thing but in a more convenient way (Again, no oscilloscope is needed here either). Details on Videos 48 and 49. the 3 variants are in fact a “natural progression” of 1 project ideea

@ovi4 Thank you, you too Larry. I should have known, I’ve watched all of Mt. C’s videos. But these where a while back. I must watch them again though. It was the Mnemonic that threw me.

@richlem

I’m working on the sift no switching now. Its giving me troubles. following the signal path the 3rd stage amp after that seems to lose the signal. I’ve replaced

the 4.7uf cap twice . also the 10000uf cap is acting like a dead short. take a long time to charge at 9v. going to try a 3000uf in place of my be 1000. not working yet.

I did build the original foil side tester. but I adjusted the size for dip packages I imported the circuit diagram into Inkscape increased the size 150%

came out good.

heres a links pics

https://imgur.com/o0wuSgh

@jpklitz It sounds as if you have a short path to GND somewhere. Try following the signal with an oscilloscope but leave the volume pot cursor lead up in the air (as in: do not solder any wire to it at all) and measure the final output level directly at the pot’s cursor (making sure the pot is on the maximum volume position) Tip: keep in mind that Tantalum caps are extremely “temperamental” when it comes to voltage polarity and maximum voltage applied to them. Re-check / retest your tantalum caps for short-circuit and make sure their voltage rating is “plenty” over the supply level. You’ll be surprised. Tantalum caps can short in an instant (no warning!) even in cases when you “mistakingly” apply the voltage source in reverse for a “mere” fraction of a second regardless of how powerful or weak (IE: a lame and tired 9V battery) the power supply might be! And… it goes without saying, re-check your third-stage transistor. It should be fairly easy to spot the problem. After all is a fairly basic 3-stage audio amp.

@ovi4 Agreed, I had a cap in a 465 scope that was good, next time I turned it on shorted with no warning. Couldn’t see anything until I removed it from circuit and the short went away. Still looks brand new.

Hello All. I am just putting the component list together and am hitting a roadblock for the LM3914V display driver chip. 
Every electronic store lists it as discontinued. They list some substitutes but their wiring does not look the same as the LM3914v.

Is there a proper substitute chip I am not seeing.

How did you successful builders overcome this.

73

Chris / VE3CV

Hi, there are still some new old stock (sometimes) on eBay and / or Amazon  but the alternative will be the LM3914  or its counterparts  such as LM3915N  but they are both in DIP  package (Thru hole style package) meaning a re-design of the PCB layout is needed but not hard to achieve at all (considering you are willing to spend the time to adapt it) As a matter of fact MCL himself  used an LM3915N (DIP) on one of the earlier variant of the: << Cap leakage tester>>  project (back in April 2018) and in the case of current project the SIFT tester it should work as well as it covers the exact same functionality (LED bar graph driver).

@ovi4 Thank you.