ESR meter - self test

[Harry Bloomfield]

As a result of the earlier thread on ESR testers, I ordered one from HK which turned up yesterday. This one Ebay Item number: 171023267112

I must say I am quite impressed with its functions, except it keeps crashing - which requires its battery to be removed to reset it and its lack of any details or instructions.

I have accidently found it some built in diagnostics which has aroused my curiosity. If two of the test pins are shorted, then the test button is pressed, it carries out a series of seven diagnostic self tests in sequence - T1 through T7.

As said, I'm struggling to find any information on this unit at all particularly the T1 to T7 self tests - has anyone come across anything which might be of use please?

[Lee]

Have the same one, mine is ok, are you using a decent battery? ;) All I found was:

which suggests the original idea/design was from a guy called Karl-Heinz and there is a link to his web site...

Lee

[Harry Bloomfield]

I have tried an older good battery and a new cheapie with the same results. I'm just waiting for a NMi rechargeable to charge up. What I'm getting much of the time, is a row of blocks in the top line of the display and/or some odd character remnants again in the top line. It reports the battery as OK as it boots, but if it crashes it is difficult to get it operable again and it seems quite random.

[Lee]

On my one the display is removable, assuming yours is as well then it might be worth checking the the two caps near the voltage reg - as much to see if they are fitted ;) As I'm sure you've noticed there isn't exactly a lot to it apart from the micro! :)

Lee

[Bob Minchin]

I'd contact the selling and tell him it is FUBAR. Perhaps send them a photo or two for the locked up display. I've generally found far eastern vendors quite responsive in either sending refunds or replacements. The chances of sorting it out are slim even with lots of supporting info. Like Lee, I bought one of these and it is fine. It could be corruption of data between the processor and the display. I have a an Arduino project I'm working on where I write to the display certain non varying parts of the output (text) at boot up and then later add just the changing parts (results of calculations) Sometimes the text gets corrupted and that requires power cycling to clear it. Another thing worth checking is the clock oscillator. I can't recall if it is a crystal or ceramic resonator. Bob

[Harry Bloomfield]

Thanks Lee, I have managed to grab some good useful info from the links.

I have already emailed the seller and sent him links to photos of the problem, but they are claiming they cannot access the links (?)

[Harry Bloomfield]

There are two electrolytics close to (below) IC2, but there is a large area to the right which is unpopulated - some sort of voltage inverter area.

[Lee]

Same as mine. Clock or power is about all you can check, unless you have another display to check it with - and then you'd have to make sure it was wired to the same pinout... I'd be inclined to agree that the micro (or possibly the display) is fubar.

If you can't send it back then as an exercise in education, it might be worth removing the voltage reg and hooking up a bench supply but I doubt it would prove much.

Lee

[Adrian C]

Check their ESR, you'll need a meter. Ebay Item number: 171023267112 ?

:-p

[Theo Markettos]

To quote what I posted in the previous thread... get ready to use Google Translate:

There are two versions. The one with two banana/screw sockets:

uses a stc12le5a60s2 microcontroller, and: have some info about the algorithm if you translate from Chinese (though quite hard to follow)

Aha! This:

has an attachment with the schematic and the source code.

The one with three test points (Harry's):

More digging. Apparently the three-input type marked 'Booster edition Transistor L/C ESR tester' on the PCB are all knockoffs of a project by Markus Frejek based on an ATmega168. Another thread on them:

Karl-Heinz Kuebbeler has extended it (in German):

Theo

[Harry Bloomfield]

on 07/06/2013, Harry Bloomfield supposed :

Now all sorted - they have agreed to just post off a replacement. I have found it to be less inclined to crash when run from a rechargeable PP3, but it does still crash.

I have also managed to track down the design information, use instructions and etc.. The designer is suggesting there ought to be some caps as close as possible to the processor, but there are none on the PCB close to it at all, so I suspect the replacement, when it arrives will act similarly.

Odd that it will run for hours (on the rechargeable), then suddenly start to crash when it will be difficult to get it to work properly, but once it works again it will be fine for several more hours.