$20 LCR ESR Transistor checker project

[stj]

drift wont be an issue if used indoors, it's not like your using it in snow one day and baking heat the next.
there is equipment that could apply to, such as multimeters - but not a component tester.

[timelessbeing]

You could be right. I actually don't know if you took it outside where there is a 20 deg difference, how much the measurements actually change.

But lower tolerance resistors also change more over time don't they? I suppose this would be mitigated by running the calibration every year.

[j395]

advice on sourcing these components, but had no luck

use 1K/1M multi-turn trimmers (like Bourns 3266/3296/3299), calibrate  with accurate ohmmeter

[CheckOne Two]

Hi all .. been using the m1.32 FW for a while now but just had the srv05-4 diode array give up on me (nothing to do with caps) ... I've been trying to find the spec of it to get a better quality replacement but it's obviously a really cheapo part and none of the aliexpress etc. ads have any spec on them. I'd rather replace with a better quality part than any more of these V05's.

I notice that a few of you are using a relay and it's also documented in the manual ... seems like a good idea to me ... can any of you who've been using a relay without problems for a while now recommend me a part number or suitable spec?

I took the opportunity to update to the 1.34 firmware but I have noticed that it doesn't ask for a capacitor anymore while self testing/calibrating ... (I've checked back over the files for compilation a couple of times now and also compared them to my last settings and can't see anything obviously out of place ... has anybody else noticed this or is it calibrating the same as it did before for the rest of you?

[timelessbeing]

I don't recommend buying a relay. The relay circuit will cost you more than a new 328P.
Salvaged parts are ideal, and almost any two pole relay can be made to work.
Obviously, a 5V coil will be easier to hook up. I would use something small so your battery lasts longer.

[madires]

Hi all .. been using the m1.32 FW for a while now but just had the srv05-4 diode array give up on me (nothing to do with caps) ... I've been trying to find the spec of it to get a better quality replacement but it's obviously a really cheapo part and none of the aliexpress etc. ads have any spec on them. I'd rather replace with a better quality part than any more of these V05's.

www.onsemi.com/pub/Collateral/SRV05-4-D.PDF, Littelfuse, Bourns ...

I notice that a few of you are using a relay and it's also documented in the manual ... seems like a good idea to me ... can any of you who've been using a relay without problems for a while now recommend me a part number or suitable spec?

I'm using Fujitsu FTR-B3 series (FTR-B3CA4.5Z) for testing. Anyhow, I prefer to simply discharge any cap before connecting it to the tester.

I took the opportunity to update to the 1.34 firmware but I have noticed that it doesn't ask for a capacitor anymore while self testing/calibrating ... (I've checked back over the files for compilation a couple of times now and also compared them to my last settings and can't see anything obviously out of place ... has anybody else noticed this or is it calibrating the same as it did before for the rest of you?

The m-firmware doesn't ask for a self-adjustment capacitor, but the k-firmware does. When running the m-firmware perform three checks of a film cap (100nF - 2.2µF) in a row before running the self-adjustment. It's explained in the README file. The hardware option for a fixed self-adjustment cap is also supported.

[CheckOne Two]

Thanks for the info both of you .. I'll see if I can find a scrap relay.

I'm usually pretty vigilant at discharging and normally use my LCR meter for caps but still have the odd brain fog moment once in a while and broken test equipment can be a real inconvenience so I always think any extra protection for test gear is a good idea for me.

That's good to know that the 1.34 FW doesn't ask for a ref cap ... I must be remembering way back to when I got the kit at first and it had 1.12  k-FW on it ... should be working fine then ... 

[MAntunes]

Hi guys!

When I was soldering my AY-AT kit I dropped the SRV05-4 chip and I can't find it.
Is this component really needed? Can the tester work without it until I get a replacement?

Also, where can I get the latest firmware (.hex file) for using with a 20MHz crystal? What is the difference between the K and M firmwares?

Thank you!

[madires]

The tester works also fine without the SRV05-4 (input protection). The m-firmware's README file explains the differences between both firmwares. IIRC, there is no ready-to-program version for 20MHz. So I'd recommend to compile it yourself.

[MAntunes]

The tester works also fine without the SRV05-4 (input protection). The m-firmware's README file explains the differences between both firmwares. IIRC, there is no ready-to-program version for 20MHz. So I'd recommend to compile it yourself.

Is the README you are talking about the one inside this folders? More particularly the 1.34m?
https://github.com/svn2github/transistortester/tree/master/Software/Markus

[madires]

Yes, each firmware tgz archive includes the README.

[Southerner]

Is there a repository for the current and past firmware versions?  Where is it?
Can newer or newest versions be flashed to older hardware versions?

I have 2 or 3 different GM328's.  I keep trying to find a case for one and even the vendors saying they have it end up sending me the current (new) version case which does not fit older versions.

Also my present stock of the GM328's seem to have one shortfall that I hate.  That is that they do not read capacitor values down to say 4pf.  In fact, one of them will not even read down to 22pf!

Thank you.

[timelessbeing]

Is there a repository for the current and past firmware versions?  Where is it?

The very first page of this topic.
https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/msg195143/#msg195143

Can newer or newest versions be flashed to older hardware versions?

Yes. Flashing erases everything so you're essentially starting with a blank chip.

they do not read capacitor values down to say 4pf.  In fact, one of them will not even read down to 22pf!

Did you calibrate your device? Measuring small cap values is very sensitive. Even the socket will affect your measurement, and probe leads will invalidate it completely.
https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/msg1269056/#msg1269056

You can try adding caps in parallel.
https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/msg1753007/#msg1753007

[tonewheel]

Hello all,
I have one of the LCR-T4 testers that looks identical to the one
Dave reviewed: Dave's review. I just want to check if this one is suitable for flashing with newer firmware. I have a USBTiny to do it with.
Thanks for any help.

[madires]

Yep, you can update the firmware. For the k-firmware use mega328_T3_T4_st7565 or mega328_T4_v2_st7565, and for the m-firmware see the Clones file.

[tonewheel]

Thanks very much. The only one I've come across is https://github.com/svn2github/transistortester/tree/master/Software/Markus. Latest seems to be 1.34m. Is that the 'm' version you mention? I haven't found any other yet.
Thanks again.

[madires]

That's right! It's the latest m-firmware. You'll find the k-firmware in the "trunk" directory.

[tonewheel]

Thank you. Can anyone confirm that the 6 holes next to the crystal are the SPI pins please? I've only just realized that they aren't marked. If they are, has anyone worked out which pin is which?
Thanks again.

[timelessbeing]

Why don't you just buzz it out? It's a beginner level electronics skill.

[tonewheel]

Of course, it didn't even cross my mind. I suppose I'm not a beginner yet, but I hope to be one day.
Cheers.

[JoeO]

Please come back here and post the results.
Thanks

[tonewheel]

Please come back here and post the results.
Thanks

Certainly. At the same angle as the picture I posted above (crystal on the right):
MISO     VCC
SCK       MOSI
RESET    GND

This is the same layout as the connector from the USBtiny, so maybe it's standard, I don't know.

Decided to read the data out of the chip first. Read fuses and EEPROM but got a problem with the flash. Posted avrdude image below. Seemed to be reading but said "flash is empty". I'm reluctant to try and flash it now. I want a backup before I do.

If anyone recognises what's going on there, please let me know.
Many thanks.

[Cliff Matthews]

Regardless of battery voltage, I'm starting to get a weird LCD character in some screens on my Hiland DIY M12864
Would re-flashing firmware fix this? or is this typically a fault of the LCD uC controller? - Thanks!

[madires]

This is the same layout as the connector from the USBtiny, so maybe it's standard, I don't know.

It's a standard 6-pin ISP.

Decided to read the data out of the chip first. Read fuses and EEPROM but got a problem with the flash. Posted avrdude image below. Seemed to be reading but said "flash is empty". I'm reluctant to try and flash it now. I want a backup before I do.

Despite the firmware being Open Source several clone vendors set the lock bits to prevent flash and EEPROM to be read. If you reset the fuse bits you'll have to program a new firmware anyway.

[madires]

Regardless of battery voltage, I'm starting to get a weird LCD character in some screens on my Hiland DIY M12864
Would re-flashing firmware fix this? or is this typically a fault of the LCD uC controller? - Thanks!

It seems to be the same bad character in all cases. Interesting! If reprogramming doesn't help it could be an issue with the LCD driver.