Author Topic: $20 LCR ESR Transistor checker project  (Read 1495960 times)

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Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #5025 on: August 18, 2018, 03:47:16 am »
It is feature of work of k-firmware in the cycle mode.For the test of "small" capacities at first on test pins 1-3 in the mode of a cycle we measure any capacity above 25pf, then without pressing the Test button we connect on the same pins "small" value capacitor from 1pf. :)

Thanks for the explanation! I've missed that feature.
 

Offline Discotech

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Re: $20 LCR ESR Transistor checker project
« Reply #5026 on: August 18, 2018, 06:55:22 am »
I've found another solution of putting in a higher rated cap it can detect, removing it so cap value resets to 0 then place small cap and it will show value
Seems strange it can detect value but only if test is already active ?
It is feature of work of k-firmware in the cycle mode.For the test of "small" capacities at first on test pins 1-3 in the mode of a cycle we measure any capacity above 25pf, then without pressing the Test button we connect on the same pins "small" value capacitor from 1pf. :)

On further messing around I've found if you go through the menu and specifically choose to measure capacitor it allows small value caps to be tested without using a higher value

Seems strange that you can't just put in cap, then turn on the tester to test automatically and instead have to go through menu first to do it for low values, I'm not sure I'd call it a feature as it feels more a hindrance  :-//
 

Offline indman

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Re: $20 LCR ESR Transistor checker project
« Reply #5027 on: August 18, 2018, 05:29:38 pm »
Did you attentively read a manual from Karl-Heinz?He has explained everything concerning measurements of small capacitors in the automatic mode! :)
"23.Capacitors with value below 25pF are usually not detectet, but can be measured together with
a parallel diode or a parallel capacitor with at least 25pF. In this case you must subtract the
capacity value of the parallel connected part. For processors with at least 32K flash memory
the tester changeover to a special capacity meter function, if a capacitor with more than 25pF
is once measured at TP1 and TP3. In this capacitor meter mode you can measure capacitors
below 25pF at TP1 and TP3 directly."
"In the same way the tester changes to a capacity
meter function, if a capacitor is detected at TP1 and TP3. This operation mode is indicated
with a [C] at the right side of the first display line. With this capacity meter function capacity
values are shown down to 1pF. Only for the automatic start you need a capacitor with more
than 25pF. Both special modes can be finished by a key press. The tester will then continue
with the normal tester function."

For menu function "Capacitor meter 1-3":
"Capacitor meter with the 1-3 symbol the tester changes to a capacitor meter function at TP1
and TP3. This operation mode will be marked with a [C] at the right side of the first display
line. With this operation mode capacitors from 1pF up to 100mF can be measured. In this
operation mode the measurement is repeated without key press. With a key press the tester
finish this operation mode and returns to the menu. In the same way as with resistors, the
tester changes automatically to the capacitor meter function, if a capacitor between TP1 and
TP3 is measured with the normal tester function. After a automatically start of the capacitor
meter function the tester returns with a key press to the normal tester function."

« Last Edit: August 18, 2018, 05:42:26 pm by indman »
 

Offline nakcho

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Re: $20 LCR ESR Transistor checker project
« Reply #5028 on: August 20, 2018, 06:04:19 am »

good morning I have a problem that more than 6 months ago I can not

fix it hehe I have no experience with programming ... I tell you my little problem ... buy a transistor tester M328KIT   https://www.ebay.com/itm/GM328-Transistor-Tester-Diode-Cap-ESR-Volt-Freq-Meter-PWM-Signal-Generator-DIY/152443029396?epid=577875436&hash=item237e500794:g:l3wAAOSw4A5YqU1i   
the original firmware version was 1.12K the problem is that I stopped working ... from one day to another did not want turn on only white screen and off ... well here comes my next step .. eh recorded again the firmware that I downloaded from this web and the problem persists on white screen with some firmware and others take to appear something like that is slow. and lately I found a firmware version 1.12k and 1.13k 1.33m turns on as fast as I should and starts asking me to make the short circuit with the 3 points 1 - 2 - 3 I do it ... but it does not do anything ... it keeps showing me the short-circuit message ... after a few minutes (1 to 2 mi nutos) keeps doing a test I guess ... until you get to ask me to put a capacitor of 100NF I guess that ... because it shows that on the screen ... when putting the capacitor ... it stays there branded and there it does not come out ... that same problem happens to me with 3 or 4 firmware that seems to work fine but in the end it remains if the rest of the effect shows white screen or it takes too long to show something on the screen ... can someone help me to put the firmware again to this version (I have not modified anything the device is as I buy it ... I'm only interested in uploading the firmware again and it works as before ..) please .... I need a little help

my English is terrible ... I hope you understand me something
 

Offline Willem52

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Re: $20 LCR ESR Transistor checker project
« Reply #5029 on: August 20, 2018, 06:56:54 pm »
Did you already replace the cpu?
If not, I would replace it for a new one and program it.
 

Offline nakcho

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Re: $20 LCR ESR Transistor checker project
« Reply #5030 on: August 20, 2018, 11:52:32 pm »
Did you already replace the cpu?
If not, I would replace it for a new one and program it.

good morning ... if I actually change it because the original wine when I recorded it so many times I changed the fuse I was blocked ... well now I bought 2 more cpu for tests and the same happens with both .. in the original also the same thing happened to me ... record the cpu with this file http://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/?action=dlattach;attach=445891 1.13 that they simulated the proteus and it starts everything well in its time ... the only thing is that it does not detect anything .. when wanting to program something ... and if I do selft test it does not detect the short circuit ... ... which would have to install and configuration of the fuse ... although I'm already ... tested with this line with all the firmware .. please can someone give me a hand I'm only interested in recovering the tester
avrdude -c usbasp -p m328p -B 0.5 -e -U flash:w:"TransistorTesterhex":a -U eeprom:w:"TransistorTester.eep":a -U lfuse:w:0xF7:m -U hfuse:w:0xD9:m -U efuse:w:0x04:m
 
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Offline indman

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Re: $20 LCR ESR Transistor checker project
« Reply #5031 on: August 21, 2018, 02:03:35 am »
nakcho,сan you make small video how the tester works with an firmware 1.13k and how you do calibration? Then it will be simpler to us to solve this problem.
 

Offline nakcho

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Re: $20 LCR ESR Transistor checker project
« Reply #5032 on: August 21, 2018, 01:28:56 pm »
nakcho,сan you make small video how the tester works with an firmware 1.13k and how you do calibration? Then it will be simpler to us to solve this problem.
good indman ... I've made a video from the start of the tester to the 100nf capacitor check. as to start does not detect any component ... then perform the calibration that asks me to make a short circuit ... in the three points 1-2-3 ... since a few minutes goes to the next step that the truth is not what does it do but it throws some data to me ... then it asks me to put a capacitor of 100NF that when putting it the truth that it does not do anything it remains enough time ... and it returns to be restarted but without any successful message ... and we continue without recognizing no data
I tested firmware 1.13 that was simulated in proteus ... is the best start ... if you delay as it did in its previous version 1.12k but with its problems of recognizing the components
here I attach the link from where I pulled version 1.13k that I do not know if it would be ok ... well ... I hope you can give me a little hand ... I thank you
here the link 1.13k
http://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/4825/
here a demonstration video

 

Offline indman

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Re: $20 LCR ESR Transistor checker project
« Reply #5033 on: August 21, 2018, 06:09:26 pm »
Ok! I have several versions of the solution of this problem:
1. Use the original version of an firmware 1.13k Rev.798 Karl-Heinz which I have attached below.
2. If you have a reliable multimeter(DMM), then define precisely what voltage of Vcc  stabilizer 7550 exit? I see on video what on the display is shown 5.13v. If it correctly, it exceeds that level which is necessary for normal work of a tester. It is necessary to achieve that voltage of Vcc was close to value 5.00v. Perhaps, it will be necessary to replace 7550 with other better voltage stabilizer(MCP1702,LP2950)!
3. Accurately remove 2 elements - protective assembly of SRV-05 and a supressor of P6KE(6V8) which I have marked on a photo in the yellow color.
4. Repeat the procedure of calibration after implementation of points 1-3. I remind you that at emergence on the display of the inscription "T4 Isolation probes", it is necessary to remove short circuit of test contacts. :)
« Last Edit: August 21, 2018, 06:22:13 pm by indman »
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #5034 on: August 22, 2018, 03:17:24 am »
The TC1 story continues. After replacing the MLCC filter caps for the Zener test voltage with a low-ESR electrolytic (higher voltage and no DC bias derating) I had still issues with the power supply. While checking voltages and other components  I've noticed that D2 (rectifier diode for the Zener test voltage) gets hot also as the MLCCs did. My guess is that D2 has a too low reverse voltage rating causing current to flow back into the flyback transfomer. So I've replaced the diode with another Schottky with a higher reverse voltage and now everything seems to work fine. Also the battery current draw dropped about 50-70mA. Don't we love cheap dodgy parts? >:D
 
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Offline indman

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Re: $20 LCR ESR Transistor checker project
« Reply #5035 on: August 22, 2018, 04:16:58 am »
Madires, at the owner of 2 identical LCR-TC1 one of device strong leakage of the accumulator was observed, charging lasted not for long, the analysis and check  have revealed breakdown of one of C2-C4 capacitors - there was resistance on the "ground" slightly more than 1 kOmh! From + 5v the serviceable tester consumes current from 24,6mA to 44mA.

I would like to return to a problem of C11-C12 and to explain what it is desirable to apply high-quality capacitors with penetrative voltage not less than 100v to. Below I will attach the photo of impulses which are developed by a chip of U5 with a frequency about 1 MHz for food of primary winding of the pulse transformer.
 Impulses voltage in this chain reach values from -17,6v to 65,6v, and their amplitude depends on accumulator voltage, the charge is higher, the amplitude is higher.
« Last Edit: August 22, 2018, 06:00:36 pm by indman »
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #5036 on: August 22, 2018, 04:36:02 am »
Yep, a filter cap rated for 100V makes sense. After replacing the dodgy parts the Zener test voltage is nearly 50V DC without load (just the the voltage divider for measuring the voltage).
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #5037 on: August 24, 2018, 01:58:40 am »
Since my TC1 works fine now I've measured the total standby current for the tester including the alternative power control circuitry (compatible with k/m firmware). It's 5µA. User zappenduster noted 15µA standby current for the original design with U4 (http://www.eevblog.com/forum/testgear/tc1-lcr-meter-transistor-tester-fix/msg1622248/#msg1622248). Not too shabby :)
 

Offline seanspotatobusiness

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Re: $20 LCR ESR Transistor checker project
« Reply #5038 on: August 29, 2018, 11:49:09 pm »
I'm not sure whether I want to use a (AY-AT) tester with an 8 MHz or 16 MHz crystal. Would one of these things form a tight connection while allowing the crystal to be changed? I'm afraid that the crystal would be too loose because it's not sprung like a DIP socket:



Is the only advantage to double the resolution of capacitance measurements? I'm not really interested in using a colour-screen. I was planning on buying a separate ATMEGA328 so I could experiment with the custom firmwares but easily go back to the original configuration when I inevitably fail.
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #5039 on: August 30, 2018, 12:23:05 am »
I'd try the non-precision type socket terminal with the fork contact or a non-precision IC socket. The higher MCU clock frequency will improve any time based measurement (not just the capacitance) and also allows higher frequencies for PWM and square wave (and frequency counter).
 
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Offline seanspotatobusiness

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Re: $20 LCR ESR Transistor checker project
« Reply #5040 on: August 30, 2018, 12:35:23 am »
Thanks but I'm not sure what you mean. Could you possibly post a Google image search of the kind of thing you're talking about? I need a socket that I can put into the space which the crystal is meant to go in.

Also do you know whether this appears to be a usable AY-AT clone? https://www.aliexpress.com/item/Multifunctional-Tester-GM328-Transistor-Tester-Diode-Capacitance-ESR-Voltage-Frequency-Meter-PWM-Square-Wave-Signal-Generator/32815238753.html?spm=a2g0s.9042311.0.0.7dfe4c4d4D7a2i
I read in this thread that some people were laughing at a version with a 10K resistor near the rotary encoder and this one appears to have 10K resistors on either side of the rotary encoder. I don't know what those resistors are for or why 10K values are funny...
 

Offline Willem52

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Re: $20 LCR ESR Transistor checker project
« Reply #5041 on: August 30, 2018, 01:00:36 am »
If I remember correctly, they laughed because in that specific picture that 10 K resistor was loose.
 
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Offline madires

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Offline seanspotatobusiness

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Re: $20 LCR ESR Transistor checker project
« Reply #5043 on: August 30, 2018, 02:04:46 am »
Thanks very much. I already have some of the first kind; I didn't realise it has springy contacts.

Incidentally, I just made a feature request for the custom firmware: https://github.com/svn2github/transistortester/issues/2 - do you know whether it is a feasible request to have an LED tester function where you can specify the current you want to test at and then the tester tells you the forward voltage needed to pass that current? Normally, it's a bit of a hassle to determine this with two multimeters.
 

Offline timelessbeing

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Re: $20 LCR ESR Transistor checker project
« Reply #5044 on: August 30, 2018, 04:33:58 pm »
Would one of these things form a tight connection while allowing the crystal to be changed?



I use machined pin headers to socket crystals, and they work fine.
 
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Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #5045 on: August 30, 2018, 08:10:09 pm »
Incidentally, I just made a feature request for the custom firmware: https://github.com/svn2github/transistortester/issues/2 - do you know whether it is a feasible request to have an LED tester function where you can specify the current you want to test at and then the tester tells you the forward voltage needed to pass that current? Normally, it's a bit of a hassle to determine this with two multimeters.

The repo at github is just an automatic clone of the original one at mikrocontroller.net and isn't maintained by anyone. So please post suggestions to one of the forums (mikrocontroller.net or eevblog.com) or send an email.

The tester's circuit doesn't support a variable current adjustment. Therefore it isn't possible to implement the feature you've suggested. BTW, the standard diode check provides a current of about 7mA.
 
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Offline seanspotatobusiness

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Re: $20 LCR ESR Transistor checker project
« Reply #5046 on: August 31, 2018, 05:33:39 am »
Incidentally, I just made a feature request for the custom firmware: https://github.com/svn2github/transistortester/issues/2 - do you know whether it is a feasible request to have an LED tester function where you can specify the current you want to test at and then the tester tells you the forward voltage needed to pass that current? Normally, it's a bit of a hassle to determine this with two multimeters.

The repo at github is just an automatic clone of the original one at mikrocontroller.net and isn't maintained by anyone. So please post suggestions to one of the forums (mikrocontroller.net or eevblog.com) or send an email.

The tester's circuit doesn't support a variable current adjustment. Therefore it isn't possible to implement the feature you've suggested. BTW, the standard diode check provides a current of about 7mA.

Thanks. What if it just ramped up the voltage until the desired current was reached? Wouldn't that achieve the same thing? Is 7 mA the upper limit?
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #5047 on: August 31, 2018, 09:07:21 pm »
Nope, the tester uses two fixed resistor values (680\$\Omega\$ and 470k\$\Omega\$). Please see https://github.com/svn2github/transistortester/blob/master/Doku/trunk/pdftex/english/ttester.pdf for the circuit diagram.
 
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Offline MrData

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Re: $20 LCR ESR Transistor checker project
« Reply #5048 on: September 02, 2018, 12:26:24 am »
Hello, can you guys help me out to find wich firmware goes with this device?

Thanks in advance.
 

Offline timelessbeing

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Re: $20 LCR ESR Transistor checker project
« Reply #5049 on: September 02, 2018, 04:42:02 am »
I don't know but the PCB looks nice. Programming header too.
 


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