$20 LCR ESR Transistor checker project

[stj]

that sounds very cheap till you realise you dont actually need the other 99!! 

[texaspyro]

that sounds very cheap till you realise you dont actually need the other 99!! 

I've used over half of them.   I once spent a day doing tests on each one to find a "really good" one.  Total waste of time... they were all  surprisingly good and practically identical in what I was testing for. 

Decent crystals for 5 cents a whack... no way!  Next thing you will tell me is I can get rather nice GPS modules with an antenna for $7 a pop... oops, been there, done that.

[progrock]

Thanks for the links... but I bough all the parts needed to upgrade the aliexpress model to the "improved" version off arrow.com today... the Crystal was under 50 cents anyway... and everything is coming with free overnight shipping (not to mention arrow is insane with their packaging, so each part will be in it's own separate static bag, nicely labeled, etc).  Bought enough to build 2 of these, plus a few spare parts just in case.  Of course I still have to wait for the board(s) to get shipped from China... but oh well.

Sadly, I need to test a handful of MOSFETs on an arduino based spot welder I have that is failing... seems like this board would be perfect for that... but I believe its not too hard to accomplish with my fluke multimeter... just a few step process for each mosfet if I'm not mistaken.  But definitely glad to find this device to make things a little easier in the future.

[stj]

something i noticed with intermittent or slightly questionable mosfets is you often find the reverse-diode has vanished / failed open-circuit.

[progrock]

I'll have to check that out... I know they are pretty good mosfets (well, tried and true at least)... legit (not a chinese copy) IRF1404.  Just gotta desolder a couple of layers of PCBs to get to them, and figure out the correct way to test with my Fluke 15B+... never tested any FETs with it before (actually, last time I tested a FET was nearly 10 years ago in a college electronics lab... and I've done my best to forget pretty much everything I learned at school, all I have is a piece of paper saying I have a CoE degree at this point)... it appears to have the mode I need to test, tho it's one of only 2 modes that don't have a direct mode (as in you spin the dial to select Ohms, then it appears to have 2 optional modes from there, one being what I believe is the mode needed to test a mosfet).

Def glad I'll have one of these guys next time I need to do this (hopefully).

[perieanuo]

something i noticed with intermittent or slightly questionable mosfets is you often find the reverse-diode has vanished / failed open-circuit.

For a real mosfet the diode dies first generating a short. Anyway good practice is putting external diode for power applications like inverters where the returning energy anyway is not "eated" by the internal diode.

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[stj]

well i noticed the problem when repairing low current backlight invertors in lcd tv's & monitors.

often when a fet shorts, you find the diodes are failing or gone in the remaining parts - so i used to change them as a set.

[progrock]

Thanks, great advice, and may have saved me from another headache.

[perieanuo]

well i noticed the problem when repairing low current backlight invertors in lcd tv's & monitors.

often when a fet shorts, you find the diodes are failing or gone in the remaining parts - so i used to change them as a set.

Never noticed thanks for pointing out!

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[madires]

I've started to write drivers for ILI9163 (SPI) and SSD1306 (SPI & I2C), and ordered a few displays. Hopefully the ILI9163s are not ST7735s, since they are quite similar. Many display descriptions are unclear about what you get.

[marklein]

Are all the various AY-AT boards interchangeable, or are there layout/circuit/values differences? In other words could I take the ATMega from one board and swap it with the ATMega a different board and expect them to work? THX

I have one dead tester and one good one, and the ATMega from the dead unit doesn't display anything in the known good board, but they are different vendors and revisions so... 

[stj]

they should be the same if they both say "AY-AT" on them.
either way, you cant damage anything by swapping controllers around - the critical pins are fixed. (power, crystal etc.)

[stevelup]

The primary variations are the display type and the pins used for connecting the display. If they are both using the same display type, and the display is connected in the same way, the processors should be interchangeable.

[beanflying]

Love this epic thread 

Love my evilbay tester. Crammed it into an old 2.5" Sata drive case I had. To save losing SMD components in the case I used a garden tap washer glued to the board which is a neat fit to the top of the case. Some cheap and nasty clips fitted to a header go in the Sata pouch in the toolbag.

Currently it has an 8-20V Linear regulator and a Deans Mini plug fitted to the end. So fairly much any external DC supplies to power it. I might fit up an internal LiPo/Charger etc but cells are to fat

[perieanuo]

Love this epic thread 

Love my evilbay tester. Crammed it into an old 2.5" Sata drive case I had. To save losing SMD components in the case I used a garden tap washer glued to the board which is a neat fit to the top of the case. Some cheap and nasty clips fitted to a header go in the Sata pouch in the toolbag.

Currently it has an 8-20V Linear regulator and a Deans Mini plug fitted to the end. So fairly much any external DC supplies to power it. I might fit up an internal LiPo/Charger etc but cells are to fat

For God's sake put black screws

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[beanflying]

Picky Picky Picky 

3mmx8mm "black" countersunk screws in country Australia don't grow on trees. Only the dropbears do

[perieanuo]

Picky Picky Picky 

3mmx8mm "black" countersunk screws in country Australia don't grow on trees. Only the dropbears do

Sorry the French people I'm working taught me it have to be nice, if it works that's secondary.
Anyway, paint the dam.ed screws.
Kidding, again

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[bitseeker]

Love my evilbay tester. Crammed it into an old 2.5" Sata drive case I had.

That's a good idea. Add it to the $20 transistor tester enclosure thread, too.

[stj]

enclosures are for "users", engineers dont need enclosures. 

[bitseeker]

LOL. Yeah, the lab is the enclosure.

[nakcho]

ood collaborators of the forum ... I have a compontens tester on the board says 2578AY-AT I miss the firmware is the white screen a while and nothing happens ... uh .. tried to burn a firmware but none successful does not show me nothing ... I do not know what is wrong ... one of the firmware I get 99 ::: 99 and then it turns off the only thing I want is to recover my tester can I get a link with the correct firmware? I am using Extreme Burn 1.4 ... I do not know if it will be fine but what I do is put the memory to erase and load the new Hex ... nose if I had to configure something else in the program ... please can you help me. .. as I said the only thing I want is to recover my tester ... from now thank you very much

[Willem52]

If flashing new firmware, do not forget to set the FUSES correctly, please!


SVN firmware repository "mega328_color_kit" folder:
https://www.mikrocontroller.net/svnbrowser/transistortester/Software/trunk/mega328_color_kit/

I still use the SVN 700 compilation from STJ (attached).

[nakcho]

If flashing new firmware, do not forget to set the FUSES correctly, please!


SVN firmware repository "mega328_color_kit" folder:
https://www.mikrocontroller.net/svnbrowser/transistortester/Software/trunk/mega328_color_kit/

I still use the SVN 700 compilation from STJ (attached).

again ... excuse my gnorancia .... I'm in full fight with this ... I attached an image of the fuse settings please help me ... install the firmware and only the voltage appears ... and then it turn off I think it is due to lack of fuse settings --- you help me with the correct configuration of the fuse? the crystal is 8Mhz

[madires]

For ATmega328 with external 8MHz crystal:
Low Fuse: f7
High Fuse: d9
Extended Fuse: fc

[Per Hansson]

Parte baja Fusibiles = F7
Parte alta Fusibiles = D9
Fusibles extendidos = FC
Fusibles de Bloqueo = Do NOT select "escribir" on this one, it is used for write lock
Calibración = No idea what "calibration" this is for.

This should correspond to:
\-U lfuse:w:0xf7:m \-U hfuse:w:0xd9:m \-U efuse:0xfc:m

EDIT: madires was quicker to write than me