Author Topic: $20 LCR ESR Transistor checker project  (Read 3408351 times)

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Offline imidis

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Re: $20 LCR ESR Transistor checker project
« Reply #3150 on: January 18, 2017, 11:33:24 pm »
Thank you, will give that a shot!  :-+
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Offline casinada

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Re: $20 LCR ESR Transistor checker project
« Reply #3151 on: January 19, 2017, 07:05:47 am »
Is this a new Version?
It measures Temperature, Humidity and test infrared if you test the right sensor (modes 14, 15, 16 ??)
http://www.ebay.com/itm/Transistor-Tester-LCR-Diode-Capacitance-ESR-meter-PWM-Frequency-Signal-Generator-/172198005211?hash=item2817cd09db:g:aOsAAOSw2xRYPnuL

 :)
 

Offline bitseeker

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Re: $20 LCR ESR Transistor checker project
« Reply #3152 on: January 19, 2017, 07:17:05 am »
That looks like the AY-AT version. It's fully loaded.
TEA is the way. | TEA Time channel
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #3153 on: January 19, 2017, 01:15:05 pm »
News from the developer's bench. I've ordered a bunch of coils in the range of 4.7 up to 150mH to tackle the compensation for high value inductors. I'm also waiting for a few servos for testing the new servo checker. The alternative PWM generator with variable frequency and duty cycle for testers with rotary encoder is working fine. The display of MOSFETs includes R_DS and Vf of the body diode. The IR RC detector/decoder can handle a fixed IR receiver module (either probes or fixed). And some PCF8574 based LCD backpacks are on their way to me after a Duncan sent me his modifications for driving such a backpack. But this needs more work to support compatibility with other future extensions.
 
The following users thanked this post: sdttn, edavid, mauroh, hapless, bitseeker, indman

Offline imidis

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Re: $20 LCR ESR Transistor checker project
« Reply #3154 on: January 20, 2017, 01:28:02 am »
Just wanted to say thanks again stj, that works a treat! Went from 111% to 95.8%, world of difference!  :-+  :)
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Offline hapless

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Re: $20 LCR ESR Transistor checker project
« Reply #3155 on: January 20, 2017, 11:48:16 am »
Is this a new Version?
It measures Temperature, Humidity and test infrared if you test the right sensor (modes 14, 15, 16 ??)
http://www.ebay.com/itm/Transistor-Tester-LCR-Diode-Capacitance-ESR-meter-PWM-Frequency-Signal-Generator-/172198005211?hash=item2817cd09db:g:aOsAAOSw2xRYPnuL

 :)

Makes we wonder, what functionality did they remove to fit all that new code in?
 

Offline muxx

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Re: $20 LCR ESR Transistor checker project
« Reply #3156 on: January 20, 2017, 09:59:48 pm »
hi everyone

is anyone having problems with mis-detecting BJT as N-JFET? I put a BC548 in and it's detected as N-JFET with all parameters as zeroes.

I have a meter from "EZM Electronics Studio", supported by the mainline FW, with hardware very close to the original meter.
used to work OK, but with the upgrade to 1.12 there's this problem now.
LRC testing is OK. calibration performed.

thanks in advance.
 

Offline hapless

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Re: $20 LCR ESR Transistor checker project
« Reply #3157 on: January 20, 2017, 10:18:25 pm »
What revision? How many times has it happened and how many different transistors have you tried? It can happen during normal operation if
  • you hold the transistor by the leads or
  • the transistor is bad or
  • there's flux on the circuit board or
  • the power supply is low or unstable or noisy.
 

Offline muxx

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Re: $20 LCR ESR Transistor checker project
« Reply #3158 on: January 20, 2017, 11:39:41 pm »
> What revision?

1.12k
built from source
avr-gcc (GCC) 4.8.1
avr-libc 1.8.0+Atmel3.4.5-1

> you hold the transistor by the leads

use ZIF socket every time.

> there's flux on the circuit board

no, programmed AVR externally, no flux on PCB

> the power supply is low or unstable or noisy

tried two 9V 6LR61 batteries

> the transistor is bad

tried ~20 transistors (more than one specimen of some):

A952, 2N5401, C557, B772 - detected as BJT PNP.

MPS2222, C3421, TPT5609, BD139, 2SC460, 2SC1740 -- "N-JFET Id=0uA@Vg=0mV", then pin configuration.

this "Id=0uA@Vg=0mV" doesn't seem right either.

I think only NPN transistors are mis-detected.

all of the transistors I tried were previously correctly detected by the same meter, but different AVR and FW (stock from EZM).

here's the schematic:

https://www.mikrocontroller.net/topic/345717#3856301

thanks for your help.
 

Offline hapless

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Re: $20 LCR ESR Transistor checker project
« Reply #3159 on: January 21, 2017, 12:11:16 am »
Since you're saying that everything used to work well, it would make sense to me that the problem would be with the firmware. I haven't used that toolchain version in a long time. Download the latest revision (currently it's 708) of the firmware and compile it with toolchain version 3.5.4. We'll look for other possible causes if that doesn't fix it.
 

Offline muxx

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Re: $20 LCR ESR Transistor checker project
« Reply #3160 on: January 22, 2017, 11:29:43 pm »
hi

thanks for your help again.

I started with flashing the pre-built binary from SVN (r710): the result is exactly the same as above.

then I did a bit of a binary search of revisions and discovered that r500 works, but r501 doesn't. again I tried the pre-built binaries (they work) and also rebuilt myself, using 3.4.5, and it also works. so the regression (for this particular board) seems to be caused by this commit:

Code: [Select]
------------------------------------------------------------------------
r501 | kubi48 | 2015-06-03 23:53:36 +0100 (Wed, 03 Jun 2015) | 1 line

LCD_INTERFACE_MODE auch bei Textdisplay

this is bizarre. is there a developers forum/IRC? I could probably investigate further if someone held my hand.
 

Offline hapless

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Re: $20 LCR ESR Transistor checker project
« Reply #3161 on: January 23, 2017, 12:01:08 am »
No problem, but I'm sorry you're still having issues. What you're describing is beyond strange. At this point I would try programming a different MCU with r710.

This is, more or less, the developers' forum. They both come here from time to time. Karl-Heinz is usually more active on the German forum at mikrocontroller.net. I'm not aware of a way to chat with either of them, but maybe you could try the email listed on the front page of the manual to set up an IRC session. This forum also allows us to send private messages, but there's no guarantee that they will see it if you decide to send one.
« Last Edit: January 23, 2017, 12:02:51 am by hapless »
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #3162 on: January 23, 2017, 11:14:57 am »
Actually both are quite responsive ;) I'm a little bit puzzled about the problem, since we would see a lot of reports about such an issue. A while ago an user had a strange problem too, and after trying different things it turned out that his version of the compiler caused the problem (the way it did some optimizations). A later version fixed that.
 

Offline TheOnlyDocc

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Re: $20 LCR ESR Transistor checker project
« Reply #3163 on: January 23, 2017, 01:18:00 pm »
Hello,
i have a question. I was assembling this kit
bild upload
until i got to the two marked Resistors. On the PCB it says 3K3 (3,3Kohm) but i can only find two  33,3Kohm resistors in my set. Is this ok or is 3,3Kohm the right value?
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #3164 on: January 23, 2017, 02:13:10 pm »
 

Offline TheOnlyDocc

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Re: $20 LCR ESR Transistor checker project
« Reply #3165 on: January 23, 2017, 03:06:48 pm »
So i downloaded and read the PDF´s but all i can find is that this resistors should be 3,3kohm and not 33,3kohm. If i am wrong please correct me!
 

Offline Willem52

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Re: $20 LCR ESR Transistor checker project
« Reply #3166 on: January 23, 2017, 04:00:09 pm »
The resistors should be like the printed circuit board labels marked.
 

Offline TheOnlyDocc

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Re: $20 LCR ESR Transistor checker project
« Reply #3167 on: January 23, 2017, 04:09:57 pm »
Dam! My order from Mouser is already on its way. And i do not have a 3,3kohm resistor here (only in SMD 0805 size). Mhhh have to check if i can get the two resistors at a lokal shop.
 

Offline edavid

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Re: $20 LCR ESR Transistor checker project
« Reply #3168 on: January 23, 2017, 04:27:57 pm »
Dam! My order from Mouser is already on its way. And i do not have a 3,3kohm resistor here (only in SMD 0805 size). Mhhh have to check if i can get the two resistors at a lokal shop.

Did you actually measure the resistors?  It's easy to misread the color code.
 

Offline hapless

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Re: $20 LCR ESR Transistor checker project
« Reply #3169 on: January 23, 2017, 06:12:04 pm »
Dam! My order from Mouser is already on its way. And i do not have a 3,3kohm resistor here (only in SMD 0805 size). Mhhh have to check if i can get the two resistors at a lokal shop.

So why not just use the SMD components instead? Solder it to one of the vias and extend the other end with a piece of lead clipped from a through-hole resistor. No wait, no need to go to the local store to buy overpriced parts.
 

Offline TheOnlyDocc

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Re: $20 LCR ESR Transistor checker project
« Reply #3170 on: January 23, 2017, 06:24:42 pm »
Bilder hochladen

If i can use the SMD resistors i will definitely use them. I thougt i can not use them because they are only 1/8W and the original resistors are 1/4W.
 

Offline edavid

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Re: $20 LCR ESR Transistor checker project
« Reply #3171 on: January 23, 2017, 06:29:27 pm »
If i can use the SMD resistors i will definitely use them. I thougt i can not use them because they are only 1/8W and the original resistors are 1/4W.

If you look at the schematic, you'll see that 1/8W is fine.  (If it wasn't, you could put 4 of them in series parallel to make a 1/2W resistor.)
 

Offline TheOnlyDocc

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Re: $20 LCR ESR Transistor checker project
« Reply #3172 on: January 23, 2017, 06:48:23 pm »
Perfect! And thanks! Will start my Iron right away  :-+
 

Offline bitseeker

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Re: $20 LCR ESR Transistor checker project
« Reply #3173 on: January 23, 2017, 08:23:11 pm »
Don't forget to measure the 33K resistors, if you haven't already. They could have been incorrectly marked, but the correct resistance.
TEA is the way. | TEA Time channel
 

Offline hapless

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Re: $20 LCR ESR Transistor checker project
« Reply #3174 on: January 23, 2017, 09:21:02 pm »
TheOnlyDocc posted a picture showing a resistance measurement of 33.29k \$\Omega\$. One big problem with posting pictures to forums is that not everyone is always able to view them.

Edit: Hm. This forum doesn't seem to like Greek letters.
 


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