$20 LCR ESR Transistor checker project

[madires]

You'll find the latest version at https://github.com/svn2github/transistortester/blob/master/Doku/trunk/pdftex/english/ttester.pdf.

[Andbro]

Thanks 👍

[MikeLud]

I just finished building an AY-AT with all of the below upgrades. Which firmware should I use K or M? It came with 1.12k.

If you get an AY-AT Clone, the following is a list of hardware corrections to order if you would like to optimize it's operation on M-Firmware. If you normally order parts from Mouser or Digikey all information and links are provided. (No Supplier Affiliation/No Financial Affiliate Program Links) This is simply a resource to make the information easier for the next person to find.
AY-AT Clone - The Proper Mods
1.) 0.1% Probing Resistors
2.) 20mhz Crystal
3.) Correct LDO Vreg
4.) Correct Vref

Manufacturers Part Number=MPN
Mouser Part Number=MoPN
Digikey Part Number=DkPN

(3×)470k Resistors
TE Connectivity
MPN: H8470KBZA
Metal Film Resistors - Through Hole H8 470K 0.1% 100PPM
MoPN: 279-H8470KBZA
$0.97each (8/2017)
$2.91 (×3)
DkPN: PTF475KCCT-ND (not stocked)
Dk Alt:
475k 0.1% 1/8W
Vishay Dale
MPN: PTF56475K00BYEB
DkPN: PTF475KCCT-ND
$1.64each (8/2017)

(3×)680ohm Resistors
TE Connectivity
MPN: H8680RBYA
Metal Film Resistors - Through Hole H8 680R 0.1% 15PPM
MoPN: 279-H8680RBYA
$1.14each (8/2017)
$3.42 (×3)
DkPN: H8680RBYA-ND(not stocked)
Dk Alt:
681ohm 0.1% 1/4W
Note: listed as discontinued by digikey (w/available stock 8/2017)
TT Electronics/Welwyn
MPN: RC55Y-681RBI
DkPN: 985-1036-1-ND
$1.70each (8/2017)

20mhz Crystal
CTS
MPN: ATS20A
Crystals 20MHz 20pF 30ppm -20C 70C
MoPN: 774-ATS20A
$0.36 (8/2017)
DkPN: CTX1106-ND
$0.36 (8/2017)

Spare ATmega328
Microchip
MPN: ATMEGA328-PU
8-bit Microcontrollers - MCU AVR 32K FLSH 1K EE2K SRAM-20MHz IND
MoPN: 556-ATMEGA328-PU
$1.95each (8/2017)
DkPN: ATMEGA328-PU-ND
$1.96each (8/2017)

2.5 Volt 0.1% Precision Reference
Texas Instruments
MPN: LM4040AIZ-2.5/NOPB
Voltage References Prec MicroPwr Shunt Vtg Ref
MoPN: 926-LM4040AIZ25NOPB
$1.72 (8/2017)
DkPN: LM4040AIZ-2.5/NOPB-ND
$1.73 (8/2017)

5v LDO Voltage Regulator
Microchip
MPN: MCP1702-5002E/TO
LDO Voltage Regulators LDO w/ Low Quiescent
MoPN: 579-MCP1702-5002E/TO
$0.52each (8/2017)
DkPN: MCP1702-5002E/TO-ND
$0.49each (8/2017)

Total
Mouser: $10.88 (8/2017)
(+USA Econ Shipping@$4.99)
Digikey: $14.56 (8/2017)
(+ Shipping I'm too lazy to look this up)

Mouser USA Part Links Consolidated:
470k Resistors
680ohm Resistors
20mhz Crystal
ATmega328
LM4040 Vref
MCP1702 LDO Vreg

[timelessbeing]

Whichever one you like better. Grab a spare mcu on eBay to make it easier to swap back and forth.

[Andbro]

Hi,

What is the difference to use a 20Mhz 20pf and a 16 MHz 20pf?

Thanks

[madires]

Sorry, but I don't understand your question. Could you please rephrase it?

[Andbro]

Hi,

With the model AY-AT, does I must replace the crystal by 16 MHz or 20 MHz?

Thanks

[madires]

Both firmwares (k & m) support 16 and 20 MHz. It's up to you.

[bitseeker]

In other words, you don't have to change the crystal. The tester will work fine the way it is. But, if you want to change it, you can.

[broadway]

Hello everyone again,

Following this tutorial, I made the board with some modifications.





http://i68.tinypic.com/rbytmg.jpg


Modified PDF here - http://drive.google.com/file/d/1eWQ1JPqDr-VY0eYVAq7BssBGCY0T0Xl-/view?usp=sharing

I'm facing some problems:

1) Intermittent power issue. Device refuses to switch on sometimes. Have to press ON button repeatedly to get it to switch on. Soldered a 100nf ceramic cap each on input/output of 7805 and issue has reduced but it still occurs. Sometimes device switches off while probing a component. No short on caps or resistor.

2) I'm looking to replace bulky 7805 with mt3608-5v5v. Firmware thinks battery is low and tries to switch off. What code should I change in which file? R11 and R12 are probing PS input on pin 28(PC5). Do I need to change values of these resistors?

3) Looking for a cheap lcd with 4-5 segment display and simple I2C connections or equivalent. How to proceed? Code change? Compatible displays supported by firmware?

4) Any firmware on github that supports the encoder? I tried a few but the encoder stops working.

[madires]

1) Intermittent power issue. Device refuses to switch on sometimes. Have to press ON button repeatedly to get it to switch on. Soldered a 100nf ceramic cap each on input/output of 7805 and issue has reduced but it still occurs. Sometimes device switches off while probing a component. No short on caps or resistor.

Typical issues with the power section are a PNP (Q7 in your case) with a low hFE or too small caps before and after the voltage regulator.

2) I'm looking to replace bulky 7805 with mt3608-5v5v. Firmware thinks battery is low and tries to switch off. What code should I change in which file? R11 and R12 are probing PS input on pin 28(PC5). Do I need to change values of these resistors?

Please use the latest firmware and adjust the power management settings config.h. 1.20m is quite old.

3) Looking for a cheap lcd with 4-5 segment display and simple I2C connections or equivalent. How to proceed? Code change? Compatible displays supported by firmware?

The current firmware supports several graphic LCDs (mostly SPI, a few I2C, monochrome and color). See
https://github.com/svn2github/transistortester/tree/master/Software/Markus for the m-firmware.

4) Any firmware on github that supports the encoder? I tried a few but the encoder stops working.

The rotary encoder needs to be enabled in config.h and the pins are set in config_328.h.

[broadway]

@madires

Thank you for the short and quick answer 

The aluminium caps I used were 10uf/25v which I referred from fig 2.1 in ttester.pdf file. I will try changing the bc328-40 with a bc557b

There are three types of of firmware in the /Markus folder - a) ComponentTester* 2) *classic* and 3) *trendy*; What do they mean?

[madires]

I've meant the firmware with the highest version number, i.e. ComponentTester-1.34m.tgz.

[broadway]

Defining 16x02 lcd in config_328.h file gave me this error 

[j395]

seems like some files are in different encodings (CP866 etc) - need to convert all to UTF8

[broadway]

Thank you

Converting bitmaps/font_HD44780_cyr.h and bitmaps/font_HD44780_int.h to UTF8 has solved it.

Device has booted. But calibration mode is not working. Device shows component tester 1.34m on screen and it switches off 

Edit: Solved it. There is a lever in config that can enable/disable calibration via probe short method

btw, can anyone tell me what causes efuse to fail in the make fuses command

Code: [Select]

D:\component tester\ComponentTester-1.34m>make fuses
avrdude -c USBasp -B 10.0 -p m328p -P usb -U lfuse:w:0xf7:m -U hfuse:w:0xd9:m -U
 efuse:w:0xfc:m

avrdude: set SCK frequency to 93750 Hz
avrdude: warning: cannot set sck period. please check for usbasp firmware update
.
avrdude: AVR device initialized and ready to accept instructions

Reading | ################################################## | 100% 0.03s

avrdude: Device signature = 0x1e950f
avrdude: reading input file "0xf7"
avrdude: writing lfuse (1 bytes):

Writing | ################################################## | 100% 0.02s

avrdude: 1 bytes of lfuse written
avrdude: verifying lfuse memory against 0xf7:
avrdude: load data lfuse data from input file 0xf7:
avrdude: input file 0xf7 contains 1 bytes
avrdude: reading on-chip lfuse data:

Reading | ################################################## | 100% 0.02s

avrdude: verifying ...
avrdude: 1 bytes of lfuse verified
avrdude: reading input file "0xd9"
avrdude: writing hfuse (1 bytes):

Writing | ################################################## | 100% 0.02s

avrdude: 1 bytes of hfuse written
avrdude: verifying hfuse memory against 0xd9:
avrdude: load data hfuse data from input file 0xd9:
avrdude: input file 0xd9 contains 1 bytes
avrdude: reading on-chip hfuse data:

Reading | ################################################## | 100% 0.02s

avrdude: verifying ...
avrdude: 1 bytes of hfuse verified
avrdude: reading input file "0xfc"
avrdude: writing efuse (1 bytes):

Writing |                                                    | 0% 0.00s ***faile
d;
Writing | ################################################## | 100% 0.08s

avrdude: 1 bytes of efuse written
avrdude: verifying efuse memory against 0xfc:
avrdude: load data efuse data from input file 0xfc:
avrdude: input file 0xfc contains 1 bytes
avrdude: reading on-chip efuse data:

Reading | ################################################## | 100% 0.02s

avrdude: verifying ...
avrdude: verification error, first mismatch at byte 0x0000
         0xfc != 0x04
avrdude: verification error; content mismatch

avrdude: safemode: efuse changed! Was fc, and is now 4
Would you like this fuse to be changed back? [y/n] n
avrdude: safemode: Fuses OK

avrdude done.  Thank you.

make: *** [fuses] Error 1
Also, sometimes, when device is switched on with no component connected to probes, the display shows random values(T1-T2 130uF 60 ohm) and it keeps cycling with random values forever. What's going on?

[Andbro]

Hi,

If I change the voltage regulator 5v and the voltage reference 2.5v, does I must modify a value(s)  in in firmware? (exemple AY-T)

Thanks

[madires]

btw, can anyone tell me what causes efuse to fail in the make fuses command

Code: [Select]

avrdude: verification error, first mismatch at byte 0x0000
         0xfc != 0x04


Simply ignore that error. It's caused by an error in avrdude's standard configuration file.

Also, sometimes, when device is switched on with no component connected to probes, the display shows random values(T1-T2 130uF 60 ohm) and it keeps cycling with random values forever. What's going on?

Are you powering the tester with a SMPSU?

[madires]

If I change the voltage regulator 5v and the voltage reference 2.5v, does I must modify a value(s)  in in firmware? (exemple AY-T)

In most cases no changes are required. But you could check the voltage of the new reference and adjust the value in the firmware.

[Andbro]

Where I must change the new Vref value in firmware?

Thanks

[madires]

k-firmware: change value 2495 in Calibrate_UR.c
m-firmware: change UREF_25 in config.h

[broadway]

Are you powering the tester with a SMPSU?

Yes, a bench power supply

[madires]

Please try a linear power supply. SMPSUs can cause strange results (known issue).

[broadway]

Yes, powering it with 9v bat has solved it but my intermittent power issue has returned. I had replaced bc327-40 with bc557b because stores here dont keep bc557c and ordering from aliexp will take a month  will try stores in another city

Btw, there are two st7735 displays(besides the bare version) on aliexp. This and this

There is a  chip on one I don't recognize. Do you know?

[indman]

There is a  chip on one I don't recognize. Do you know?

74HC245 - 8-bit transceiver with 3-state outputs