Author Topic: TC1 lcr-meter transistor-tester fix (Read 138767 times)

madires · « **Reply #125 on:** August 26, 2021, 09:36:22 am »

You could buy a new TC-1 and add a switch for the LiPo. If you're looking for alternatives check out the AY-AT clones, e.g. GM328A, and the Hiland M644. And if you program one of the two OSHW firmwares you'll get even more features. BTW, there are two mods for the TC-1 to make it compatible with the OSHW firmwares. The hardware mod also reduces the quiescent current to a few µA.

Feliciano · « **Reply #126 on:** August 27, 2021, 01:10:47 pm »

If you easily find the spare parts you can try to fix the one you have, following the tips on the previous 5 pages (in most cases to replace the protection diodes ZD1 and/or ZD2 if you forgot to discharge a capacitor, as well as some caps that tend to leak or go short because the close to 40V on the Vz section of this device). If you end replacing the MCU, remember to reprogram or replace U4 with the alternative circuit (two transistors plus some resistors and diodes) before attempting to flash m-firmware or k-firmware.

Or because these ttesters are inexpensive, you can buy the one that better suits your particular needs. Here, the main models at a glance: https://github.com/madires/Transistortester-Warehouse/blob/master/Documentation/English/Clone-Comparison-Chart.pdf

Felipe Lacerda · « **Reply #127 on:** October 17, 2021, 02:02:37 am »

Quote from: Feliciano on August 27, 2021, 01:10:47 pm

you can buy the one that better suits your particular needs. Here, the main models at a glance: https://github.com/madires/Transistortester-Warehouse/blob/master/Documentation/English/Clone-Comparison-Chart.pdf

TC1 needs the mod to accept opensource firmware... does T7-H need it too? what is the best choice?
According to the table are the models that support upgrade to the 644.

*I want to buy a new one, but I haven't found any on Aliexpress already with the 644.

F1RVC · « **Reply #128 on:** November 20, 2021, 10:36:32 pm »

Hi, does somebody already had on a TC1 (M-tester V2.12k) a Zener value displayed always (with no component connected) at the startup?. All other functions look to be ok, if I put other kind of component , it is ok, but with no component it detect a zener and with a zener the measure is bad.
I checked 37v (approx) is here, the zener voltage is going to PA4 thru a divider by 10, Should have 3,7v here but input look to be pulled down by PA4 and the low voltage is displayed like a zener voltage. Also the Ref voltage 2.5V (TL431) is also pulled down to 0V on PA3 by the 324PA, if I isolate PA3 the ref voltage rise up to 2,5V. If I isolate the PA4 , it also diplay a zener voltage at startup with 0V value !
I do not tremember having done a bad measure with non discharged component , TC1 did it by itself one day at the bootup.

Before trying to change the ATMEGA with a new one and flash it with the original TC1 firmware provided on this thread, maybe I missed something more easy to fix this TC1?
Any advice or clue will be apreciated.
If I start in this way , I will probaly tweak it with alternative k firmware and hardware U4 mod later (but before I would like to fix it ) ...

madires · « **Reply #129 on:** November 21, 2021, 12:59:15 pm »

PA3 and PA4 should be in HiZ mode. If both suddenly short the input to ground then they most likely let the magic smoke out.

F1RVC · « **Reply #130 on:** November 21, 2021, 05:13:00 pm »

That is my first thought too, but what is the link between both of them? If a problem would have been occured on PA4 (static or capacitor discharge, etc...) why PA3 is down too ?

madires · « **Reply #131 on:** November 21, 2021, 05:36:15 pm »

I can only speculate. An over-voltage could also damage neighboring IO cells on the MCU die.

distefanom · « **Reply #132 on:** December 17, 2021, 09:04:07 am »

I would ask anyone who has the circuit made using a couple of transistors, to replace U4 so allowing me to use the free firmware kindly available here.
Since I don't have kikad on my PC, I would like if anybody could make me a screenshot of the complete circuit (I don't need the PCB layout) so I could replicate it on a bareboard.
Thanks to anybody who can help.
Mario

madires · « **Reply #133 on:** December 17, 2021, 11:41:28 am »

Please see https://github.com/madires/Transistortester-Warehouse/blob/master/Hardware/TC1-Mod.pdf!

chris2u · « **Reply #134 on:** January 29, 2022, 03:44:20 pm »

I just bought a TC1 recently....Generally all seems good....Although the micro USB connector was too far recessed for the cable to reach properly!....And don't expect the PCB to sit right down on it's supports..Probably due to the display being mounted too far off the circuit board, or maybe the supports are in the wrong place..

The zener test voltage is 23.1V (Not over 30v as other units are) and am wondering if this is normal for this model ??
This unit does not have the largish high voltage transformer but has 2 small inductors in the power supply section.

Attached is a photo of the PCB.

madires · « **Reply #135 on:** January 29, 2022, 04:14:00 pm »

Your TC1 seems to be another variation with two separate boost converters. To verify the output voltage for the Zener test you could reverse engineer the boost converter (IC and feedback voltage divider).

chris2u · « **Reply #136 on:** January 30, 2022, 07:09:15 am »

Looking at the first set of specs from AliExpress, it mentions 20V for zener....Then later specs show 30V..So yes, like a covid 19 variant ...Needs another booster!.

https://www.aliexpress.com/item/4001208715581.html?spm=a2g0o.detail.1000023.1.67d0549fikoqen

indman · « **Reply #137 on:** January 30, 2022, 08:57:32 am »

Quote from: chris2u on January 29, 2022, 03:44:20 pm

The zener test voltage is 23.1V (Not over 30v as other units are) and am wondering if this is normal for this model ?

Yes, this is normal, because as a DC-DC converter chip is used SDB628, which can adjust the output voltage range to a maximum of 28V! Exactly the same chip is used to produce a 7-9V input voltage for a 7805 stabilizer.

Felipe Lacerda · « **Reply #138 on:** February 01, 2022, 04:49:15 pm »

Quote from: chris2u on January 30, 2022, 07:09:15 am

Looking at the first set of specs from AliExpress, it mentions 20V for zener....Then later specs show 30V..So yes, like a covid 19 variant ...Needs another booster!.

https://www.aliexpress.com/item/4001208715581.html?spm=a2g0o.detail.1000023.1.67d0549fikoqen

TC-T7-H is the best version available? Is this seller reliable?

chris2u · « **Reply #139 on:** February 02, 2022, 05:41:32 am »

What I think would be nice is if you could change the colors allocated to the three inputs.
This way I could have (1) Red, (2) Black, (3) Green, which was the color of the supplied leads and test hooks.
It's would be a lot easier to identify what lead is what and what is base, collector and emitter and so on if things are the same colors throughout.

ATM I'm having to order purple test clips from China as there are not too many around locally.
Maybe some firmware genius could come up with a solution..

madires · « **Reply #140 on:** February 02, 2022, 02:38:25 pm »

The m-firmware supports color coded probes/test pins and you can set whatever colors you like.

joseff701 · « **Reply #141 on:** February 14, 2022, 04:03:59 pm »

Hi, I tried a capacitor and after the tester did not turn on anymore, I removed the zener diodes DZ1 and DZ2, now it turns on but does not work, on 1 and 2 it says there are 1.46v. if anyone can help me understand what broke.

madires · « **Reply #142 on:** February 14, 2022, 05:56:36 pm »

Toasted MCU IO pins, grilled by a charged cap. Can be fixed by replacing the MCU (and programming a firmware).

bob91343 · « **Reply #143 on:** February 17, 2022, 05:59:53 am »

My TC-1 consistently is fooled by a capacitor I have. This capacitor tests fine on my two bridges but when it comes to the TC-1 it doesn't know what to make of it. It will say unknown or give a completely incorrect value. Other capacitors from the same batch test fine.

distefanom · « **Reply #144 on:** March 04, 2022, 11:53:44 am »

Hi Madires!
After a looooong time, the micro finally arrived from china, on my workbench.
I can now program the uP with the kind free firmware available around here.
BUT, before doing it, I need now ask:
With the free firmware, do I need to replace the U4 with the two-transistor circuit?
When I program the IC, which fuse map do I need to use, so I could (theoretically) reprogram it ?
I mean that I could -after programming the uP- reprogram it as many times needed to test different FW releases?
I'm afraid that, with the wrong fuse map, after the first programing it will lock out itself, and I need to buy another uP.

Please let me know
Thanks
Mario

madires · « **Reply #145 on:** March 04, 2022, 01:15:14 pm »

To make the TC1/T7 compatible with the reference design you can replace U4 with the two-transistor circuit or reprogram U4 (https://github.com/atar-axis/tc1-u4). For the fuse bits simply run "make fuses" after editing the Makefile (both OSHW firmwares).

distefanom · « **Reply #146 on:** March 09, 2022, 07:04:46 pm »

Hi, Madires
If I don't want to do the MAKEFILE, since I Have eXtreme Burner only in my PC,
(see the attached image)
Do you know what values I should put in the Fusemap, so the uP can be reprogrammed anytime?
Please let me know
ciao
Mario

madires · « **Reply #147 on:** March 09, 2022, 07:37:45 pm »

For ATmega324 and 16 MHz quartz crystal:
- hfuse 0xd9
- efuse 0xfc
- lfuse 0xf7

distefanom · « **Reply #148 on:** March 09, 2022, 09:27:23 pm »

Thanks, Madires !!!

I'm missing "Lock fuse" and "calibration"
Leaving them as FF and blank is enough?

madires · « **Reply #149 on:** March 09, 2022, 09:56:38 pm »

Yep, simply ignore those two.


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Author Topic: TC1 lcr-meter transistor-tester fix (Read 138767 times)

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