$20 LCR ESR Transistor checker project

[vinceroger]

thanks for the reply it just seemed a good price now i know why.

[vinceroger]

is the t7 any better?
https://www.ebay.co.uk/itm/UK-Universal-LCR-T7-ESR-Diode-Triode-Capacitance-Mos-Transistor-Tester-CASE/123288444717?hash=item1cb4905f2d%3Ag%3AdEsAAOSw8lhbZAU7&_sacat=0&_nkw=LCR+T7&_from=R40&rt=nc&_trksid=m570.l1313

[Azure]

is the t7 any better?

Others may have more info, but I think it is basically the same inside as the LCR TC1.

[madires]

Yep, it's the same PCB with a different display module (dual row pin header at the right).

EDIT:
Update on my TC1's power supply issue. The problem was caused by the MLCC filter caps of the Zener test voltage. They were partly leaky and at some temperature they became even more leaky causing Vcc dips. It seems that C11 & C12 should be replaced with 0805 X7R 4.7µF 50V types from a reputable vendor anyway (haven't seen 100V for this type).

[bitseeker]

Hmm, I wonder if those MLCC were fractured inside.

[indman]

It seems that C11 & C12 should be replaced with 0805 X7R 4.7µF 50V types from a reputable vendor anyway (haven't seen 100V for this type).

Madires, http://www.farnell.com/datasheets/608985.pdf   ?

[madires]

Digikey's parametric search lists 0805 4.7µF MLCCs just up to 50V. And because the boost converter runs at 1MHz I'd prefer MLCCs over low-ESR TH electrolytics which are available for much higher voltages.

[stj]

the originals may only be rated at 25v or less, they may have used the same series they would for general logic.

[texaspyro]

An 0805 50V 4.7uF cap will probably have around 0.1uF capacitance at 50V...

[LatropEmit]

Hey everyone
I need some help with my tester. I tried to update the firmware with the mega644_LCD2004 k-firmware, but now when I try to power on the tester the LCD came on showing nothing and when I release the rotary it power of instantly.
I tried to read and search here and I know I have seen the answer somewhere but I can't remember where..

So my tester is the new one mentioned a few post ahead the Hiland M644.
I attached pictures from the display and the platine itself maybe it is easier to help with this pictures.

First I tried to flash the precopiled hex and eep then I tried to recompile it from scratch and setting in the make file some options like the right Part-No ect.
But I don't know what I have to set for the LCD.
To be honest I even don't  know if it's the right firmware to flash.. XD

Then setting the right fuses it's a other thing...
I tried with L 0xFF, H 0xD9 and E 0xFC then i tried with L 0x62, H 0xD9 and E 0xFC

But like you see not working, so now I am here to ask help

Ah if it helps originally it was a 1.12k fw on it..

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[indman]

Digikey's parametric search lists 0805 4.7µF MLCCs just up to 50V. And because the boost converter runs at 1MHz I'd prefer MLCCs over low-ESR TH electrolytics which are available for much higher voltages.

AVX 4.7μF Multilayer Ceramic Capacitor MLCC 100V dc ±20% X7S Dielectric 1206 (3216M) SMD, Max. Temp. +125°C
I think that this model of the capacitor without problems will be suitable for replacement of C11-C12.
The place on the printed circuit board allows to make it.

Ah if it helps originally it was a 1.12k fw on it..

Did you try to read this original firmware (1.12k) or it is blocked for reading?
It is necessary to make the drawing of the schematic diagram in order that it is easier to understand as the display is connected to the ATMega644 processor!

[madires]

An 0805 50V 4.7uF cap will probably have around 0.1uF capacitance at 50V...

Yep, the DC bias derating. So it's a low-ESR electrolytic again.

[LatropEmit]

Yeah I had read the fw and I think I had it dumped properly but I got it overwritten afterwards... I thought I saved the fw in a secure place but in my rush I forgot do to so

Hmm... ok shame on me, when I let everything hooked up on my breadboard then i get this problem with the LCD shutting down after releasing ^^

If I try to power on the tester when everything is disconnected it powers on remains on but display is showing nothing..

I attached another picture with the back site of the pcb. First thing that I notice is that LCD and SPI are sharing some pins...

Ok found out display is a JLX12864G-378 V2.0 
Now I have to find out how configuring the make file...



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[indman]

Ok found out display is a JLX12864G-378 V2.0
Now I have to find out how configuring the make file...

In the photo it isn't really well visible to what ports of the processor the display is connected! Can you make such table of connection of LCD to ATMega644 ports?
For example:
LCD (D6) - pin ATMega644?
LCD (D7) - pin ATMega644?
LCD (CS) - ?
LCD (RST) - pin ATMega644?
LCD (RS) -  pin ATMega644?

[LatropEmit]

Ok so I tried to trace back everything but i have some problems with VSS and CS they are connected to GND and maybe PA3...
I made a photos from the front and back site of the board. Then I overlapped both and tried to trace back..

So in sostans I have found

LCD        ATMEGA644

LEDA  -   VCC
VSS     -   GND (PA3)
VDD    -   VCC
RS      -    PB5
RST    -    RESET
CS      -    GND(PA3)
D7      -    PB7
D6     -     PB6

Like I said I have problems with VSS and CS but I attached the picture that I made with the trace lines. Black lines are on the backside of the pcb blue on the front hope I got I right ^^

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[Discotech]

How low can the GM328 version read caps ?

Trying to measure some 3pF ceramic caps and it doesn't recognise them 

[madires]

k-firmware: 25pF
m-firmware: 5pF

solution:
- take a cap with a known value, e.g. 33pF, and connect it in parallel with the cap to check
- subtract capacitance of known cap

The "Sampling ADC" of the k-firmware might also work.

[Discotech]

k-firmware: 25pF
m-firmware: 5pF

solution:
- take a cap with a known value, e.g. 33pF, and connect it in parallel with the cap to check
- subtract capacitance of known cap

The "Sampling ADC" of the k-firmware might also work.

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 ?

[indman]

LCD        ATMEGA644
LEDA  -   VCC
VSS     -   GND (PA3)
VDD    -   VCC
RS      -    PB5
RST    -    RESET
CS      -    GND(PA3)
D7      -    PB7
D6     -     PB6

The schematic of this clone almost completely corresponds to the schematic diagram from a manual of Karl-Heinz Kübbeler (March 8, 2018) on page 33 (figure 2.26) except for some details and the used display on ST7565.
Load a test firmware which I have collected. Everything has to work normally. I have checked this firmware in Proteus.
Fuse establish such LOW-F7, HIGH-D9, EXT-FC

[madires]

Actually that would be a bug. Hmm. There's another possibility. If the capacitance zero offset (determined during the self-adjustment) is larger than 25pF (k-firmware) it should also work. In this case the tester's own capacitance is large enough to work as a known cap in parallel.

[indman]

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.

[LatropEmit]

LCD        ATMEGA644
LEDA  -   VCC
VSS     -   GND (PA3)
VDD    -   VCC
RS      -    PB5
RST    -    RESET
CS      -    GND(PA3)
D7      -    PB7
D6     -     PB6

The schematic of this clone almost completely corresponds to the schematic diagram from a manual of Karl-Heinz Kübbeler (March 8, 2018) on page 33 (figure 2.26) except for some details and the used display on ST7565.
Load a test firmware which I have collected. Everything has to work normally. I have checked this firmware in Proteus.
Fuse establish such LOW-F7, HIGH-D9, EXT-FC

Soooo after checking the pins and re read the make file, and checked the config.h to see what pins are used, I realised that I have made a really big mistake....   
I didn't know what LCD controller to use in the make file..
Like I wrote it is a ST7565  so stupid me had in the make file WITH_LCD_ST7565 = 1306 AND NOT 1...
Therefore i compiled everything with the wrong settings...
Now after a quick test i got everything up and running... adjusting h-flip and now it's running without problems...

So in substance It works like a charme no extra fancy rewrite only setting everything right in the make file....

But thank you for taking the time to helping me

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[madires]

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.

[Discotech]

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 

[indman]

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."