0029 Simple testers, Atlas DCA75 finds some fakes

Peter looks at a few testers then puts the Altlas DCS75 through its paces and identifies some fake Germanium Diodes
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[@TheFlutecart]

Thanks, I have one on the way. I'll be using it to match transistors and FET's, diode checking. I'm glad you focused on the JFET measurements and tracing, few testing devises give us much detail at all on JFET's.

[@MakeOrRepair]

Glad it helped.

[@treadmillrepair754]

I have one DCA 75 Pro, is an excellent component tester. Chinese component tester can't detect IGBT's DCA 75 Pro can measured without any problem.

[@MakeOrRepair]

I have it on the desk ready to go particularly for transistors and fets when doing repairs. It was caught out on some faulty transistors that worked at low current, but which failed at high current switching but has successfully found quite a few faulty components. I need to build one with bigger range I think- yet another project on the list

[@treadmillrepair754]

@@MakeOrRepair I have the B&k 520b also. This is a powerful transistor tester, but some times transistors fail at very high current or high temp and is imposible to catch with any transistor tester that I have. Best Regards.

[@rlgrlg-oh6cc]

Interesting video. Thanks for making it.

[@MakeOrRepair]

My pleasure!

[@y_x2]

The most expansive one does not tested the dual gate mosfet...

[@MakeOrRepair]

The voltage and current outputs of almost all bugdet testers are completley inadequate to properly test most MOSFETs except the tiny ones, they just dont test enough range. I've several faulty transistors that I eventually found and other than very expensive curve tracers none of the budget testers could find the fault.

[@ebones6957]

I would like a quick check of the 74 logic chips, like those used in my frequency counter. With the Tl866 tester: can you just plug the IC into the socket and get a go/ no go result, without hooking up to a computer?

[@MakeOrRepair]

No, requires a computer for everything!

[@karlfell3768]

There is a searchable cross reference list for most HP part numbers. I have a pdf I can send over for you if it would be useful.

[@MakeOrRepair]

Thanks for the offer, I do have it, In fact I've got a few from different sources including HP journal, just in case there are any parts on one not on another, I work on quite a bit of HP so it is really useful. Unfortunately I do still come across some parts not on the list - mainly FETs it seems - I harvest them from scrap devices where possible but really handy to test a few and then between the curve tracer data and the diagram/supply voltages etc I can normally work out a fairly good substitute. I just need a better curve tracer really - but given the price it is on the "one day I'll make one list" Pete

[@holgerk.4650]

faked or not faked that is the question - I just ordered a dca75 and hope that it is a genuine one. Thank you for sharing and have a good time

[@MakeOrRepair]

an increasingly common problem

[@juliusvalentinas]

Atlas DCA Pro error shows NO Component when connected to L7912CV If I try to connect 2 wires only on any pins it detects it as zener diode. no reply from manufactuer. Does detect LM317.

[@MakeOrRepair]

I don't linke the "No component" message, I have seen it several times for unsupported components as well as faulty components - I think a more specific error message would help. That is not surprising it is specified as providing test voltages up to 12V and 12mA, The manufacturers limit the voltages and current so it can be used as general purpose tester; with higher voltages there would have to be user intervention to limit the power to make sure that some devices under test are not destroyed. A voltage regulator like the 7912 would needs a voltage well above 12 V to operate correctly, since it proably has a marking on the case you really need to test it is working. For that you would need to move the supply voltage around the 15-20V region and apply some loading in order to measure that it regulates. It would be possible to identify how it characterises using lower voltages and perhaps identify it sort of, but with some possibility of error, but it certainly would not be a proper test of regulation. The LM317 of course can work at much lower voltages. as could say a 7805.

[@robertmckelvey3091]

I have a bunch of New Old stock Motorola transistors with color bands on them how do I look those up

[@MakeOrRepair]

Not aware of any reference. Colour bands were often used to indicate beta values, or just for specific customer designations etc, however vary from manufacturer to manufacturer and sometimes on a per custmer basis. Probably just as well to just characterise them with a simple tester. Unless anyone else has any ideas!

[@MakeOrRepair]

Actually there is this www.instructables.com/From-Resistors-to-ICs-Color-Codes/ but not sure it always hangs together

[@juliusvalentinas]

Does not detect vloss for capacitors either, all chinese do.

[@MakeOrRepair]

The supported component list for the DCA75 is for semiconductors only: Bipolar transistors (NPN/PNP inc Silicon/Germanium) Darlington transistors (NPN/PNP) Enhancement mode MOSFETs (N-Ch and P-Ch) Depletion mode MOSFETs (N-Ch and P-Ch) Junction FETs (N-Ch and P-Ch). Both symmetrical and asymmetrical types. Enhancement IGBTs (N-Ch and P-Ch). Diodes and diode networks (2 and 3 lead types). Zener diodes (up to about 9V). Voltage regulators (up to about 8V). LEDs and bi-colour LEDs (2 lead and 3 lead types). Low power sensitive Triavs and Thyristors (

[@juliusvalentinas]

@@MakeOrRepair I can only say that chinese meters had diagnosed a cap that had good esr and bad leakage, it did not work on PC PSU. If only ESR70 would be used then this problem would not be found despite cost of ESR70 is 80Eur and chinese meter 5Eur.

[@MakeOrRepair]

​The DCA75 is not specified for testing capacitors at all. My reason for geting the DCA75 was that I couldn't afford the proper gear for testing semiconductors but I hoped it might find some semiconductors faults that all the others were missing, and it has helped. Not 100% sure but I think I do make the point in the video that I use and do think the cheap meters are useful for many purposes. But they are a handy cheap tool, I also do think all the low voltage and low current testers are inherently limited and each has strengths and weaknesses.

[@juliusvalentinas]

@@MakeOrRepair The Chinese testers can test zenners 18v no problem up to 30V, this one as you said only 11V :( Very overpriced if you ask me.

[@treadmillrepair754]

@@juliusvalentinas Chinese meters can't test IGBT's, DCA75 Pro can do it without any problem. Plus the curve tracer. Peak Atlas products are much better in my opinión. I have some Chinese meters, but I prefer to use renowned brands for my indtruments. Best Regards.