$20 LCR ESR Transistor checker project

[Feliciano]

Thanks for the reply indman.

So do you think it's a Vishay (formerly General Semiconductor)?

[indman]

The original manufacturer is Vishay and what is installed on your board is made in China!

[Feliciano]

Exactly! that's why I was asking whether the real maker can be guessed from the not-so-alike logo (to look for a better-matching datasheet and/or an improved aftermarket part, TVS vs Zener, etc.).

[elepo]

Hello guys. I have the LCR-T4 with stock firmware version 2.07

I would really like the in-circuit ESR measuring function so I want to update the firmware.
I know the m firmwares are for compiling yourself and k firmwares are precompiled.
I intend to use the mega328_T3_T4_st7565 k-firmware. But in the subfolder I also see a Makefile.

I know how to program an ATmega chip using avrdude with .hex files but the Makefile is confusing.
Do I have to use the Makefile?
Or is it sufficient to upload the .hex and .eep files to the chip using avrdude itself?

[madires]

You just need to program the .hex and .eep file. The Makefile is meant for compiling the firmware yourself if you want to (comes with the correct settings for the specific tester model).

[elepo]

You just need to program the .hex and .eep file. The Makefile is meant for compiling the firmware yourself if you want to (comes with the correct settings for the specific tester model).

Thank you.
I flashed it and I see a nice new firmware now with the additional functions available. 

A few questions tho:
1- It takes a bit longer to start up and to make measurements, is that normal?
2- It doesn't turn off automatically anymore, it appears that it is constantly making measurement. Do I have to do something to turn it off? Also is it okay to swap the element in it while it's still showing the previous element measurements?
3- I didn't touch the fuses. Do I have to change them? They read as follows:

Code: [Select]

avrdude: safemode: lfuse reads as FF
avrdude: safemode: hfuse reads as D7
avrdude: safemode: efuse reads as F9


[madires]

If it's just a bit longer it should be fine since the OSHW firmware usually checks more things than any modified one. Please see Karl-Heinz' excellent documentation for usage details (https://github.com/kubi48/TransistorTester-documentation). When the output of the current DUT is done you can swap the DUT. The fuse bits seem to be ok (though, lfuse should be 0xf7 for a quartz crystal).

[elepo]

If it's just a bit longer it should be fine since the OSHW firmware usually checks more things than any modified one. Please see Karl-Heinz' excellent documentation for usage details (https://github.com/kubi48/TransistorTester-documentation). When the output of the current DUT is done you can swap the DUT. The fuse bits seem to be ok (though, lfuse should be 0xf7 for a quartz crystal).

I read that but I'm still confused by the tester's behavior:

When I put the component in pins 1&2 :
- Battery voltage is not shown at the bottom of the result
- An indication letter (like [R]) is not shown at the top right of the screen
- After making a measurement, the tester turns off automatically after ~25 seconds
- After making a measurement, if I press the button a new measurement will be performed
- After making a measurement, a new measurement is possible by replacing the component and pressing the button once
- When I put in a capacitor a single measurement result is shown (result is not constantly updated)

However when I put the component in pins 1&3 or 2&3:
- Battery voltage is always shown at the bottom of the result
- An indication letter (like [R]) is shown at the top right of the screen
- After making a measurement, the tester does not turn off automatically
- After making a measurement, if I press the button once nothing happens. If I press the button again the tester turns off.
- After making a measurement, a new measurement is not possible as pressing the button has above behavior. Also putting a new part causes bugous behavior because the tester is not expecting a new part.
- When I put in a capacitor the results are constantly updated, I can tell because the ESR value keeps changing roughly every second.

I don't know if this is intended behavior or if I made a mistake somewhere.

[Feliciano]

Just in case: it's not the same to start your ctester with a long press of the button or a short press of it. In one case it can "stay on", and the other it could "auto power off". Anyways you can check that part on the makefile (k-firmware) or the config file (m-firmware).

[Enlargee79]

Hello all.

This is a gargantuan thread; I've skimmed through quite a few pages but I can't find any n00b friendly summaries or recommendations.

I would like a component tester for simple DIY/hobby/basic repair use cases, and I don't need any Dave style super high-level features. Simple component identifiaction and basic functionality testing would be more than enough for my needs.

Since these things have evolved quite a bit since ~2013 (or even earlier), does anyone have a recommendation for simply getting started, or a general overview of features? I've seen GM328/Mega328's and the original LCR-T4 style that Dave reviewed in a video, but I'm not sure which of these to get or whether something else would be more appropraiate.

[elepo]

Just in case: it's not the same to start your ctester with a long press of the button or a short press of it. In one case it can "stay on", and the other it could "auto power off". Anyways you can check that part on the makefile (k-firmware) or the config file (m-firmware).

I read that in the manual but it doesn't make any difference for me.
The only thing that makes a difference is if I insert the component in pins 1&2 or not.

[madires]

Since these things have evolved quite a bit since ~2013 (or even earlier), does anyone have a recommendation for simply getting started, or a general overview of features? I've seen GM328/Mega328's and the original LCR-T4 style that Dave reviewed in a video, but I'm not sure which of these to get or whether something else would be more appropraiate.

Please see https://github.com/madires/Transistortester-Warehouse/blob/master/Documentation/English/Clone-Comparison-Chart.pdf for a list of Transistortester clones.

[madires]

The only thing that makes a difference is if I insert the component in pins 1&2 or not.

The other pins trigger a special measurement mode. Please see chapter 1 'Features', item 30!

[elepo]

The only thing that makes a difference is if I insert the component in pins 1&2 or not.

The other pins trigger a special measurement mode. Please see chapter 1 'Features', item 30!

Ah that must be it!
Thank you very much for your help and for your work on the firmware.

[Enlargee79]

That is exactly what I was talking about. It would be great if the OP could add a link to this in the first post.

Thank you kindly.

[Tekjive]

Anyone know the difference between the LCR-T7 vs the T7-H?

@Enlargee79 I’ve narrowed my choice between these 2 as they have the most info per reading, are as accurate as you can get in this price range, etc. they are basically all the same when compared on that chart but the fact this model gives the RDS spec of mosfets is the selling point for me as I want to be able to group similar rated mosfets in same bank.

[madires]

R_DS is a feature supported by both OSHW firmwares. If your clone doesn't do R_DS simply flash one of the two OSHW firmwares. BTW, TC1, T7 and family come with an additional control MCU (kind of lock-in) which can be flashed with an alternative firmware or replaced with a simple two-transistor circuit to make it compatible with the reference design.

[elepo]

Does anyone know how the ring tester external circuit is supposed to be wired?
I see a "counter" and a "pulse in" pin and also another "counter" at the right and I'm not sure where I should connect these.

[madires]

It's explained in the m-firmware's README file. 'Counter Out' has to be connected to the ATmega's T0 pin and 'Pulse In' either to a dedicated pin or to probe #2. The same for 'Vcc' and 'Gnd'. And the 'Counter' flag is just a signal name for the schematic.

[Feliciano]

Anyone know the difference between the LCR-T7 vs the T7-H?

The Display & Controller. AFAIK T7 can be made compatible with OSHW (with the required mods madires told), whereas the T7-H isn't supported.

[elepo]

It's explained in the m-firmware's README file. 'Counter Out' has to be connected to the ATmega's T0 pin and 'Pulse In' either to a dedicated pin or to probe #2. The same for 'Vcc' and 'Gnd'. And the 'Counter' flag is just a signal name for the schematic.

Thank you!

[madires]

Anyone know the difference between the LCR-T7 vs the T7-H?

The Display & Controller. AFAIK T7 can be made compatible with OSHW (with the required mods madires told), whereas the T7-H isn't supported.

The T7-H seems to come with an S6D0117 compatible display which isn't supported yet. If someone sends me a sample T7-H I would try to write a driver for the m-firmware. However, the combination of a small display and a resolution of 128x128 pixels isn't very helpful, unless you're near-sighted or wearing reading glasses.

[elepo]

@madires are the config files used to compile the k-firmware available?
I flashed the mega328_T3_T4_st7565 k-firmware successfully.
I need the ring tester function and I have to use the m-firmware but I cannot get it working. When I press the button the LCD lights up but no text is shown. I desoldered it to make sure pin numbers are correct but it appears to have 10 pins! And there are only 5 pins in the config file.
I'm lost.

Is there perhaps a debug function where I can put an LED somewhere to at least confirm that the firmware is working?

[madires]

Have you tried the settings for the T3/T4 clones listed in the Clones file? There are two different pinouts for the display. For testing connect an LED to the probes, it should flicker while the component search runs.

[elepo]

Have you tried the settings for the T3/T4 clones listed in the Clones file? There are two different pinouts for the display.

Which file exactly? I have the clone comparison PDF and the models PDF but they don't have the pinouts.
It's very difficult to trace the pins because of the board layout and parts being SMD and vias not always being visible. But I'm sure PD4 is connected to my display which is not listed in ST7565R section of config_328.h

For testing connect an LED to the probes, it should flicker while the component search runs.

It does flicker so hopefully the firmware is working.