Author Topic: EEVblog #576 - Advantest R6142 Current Voltage Generator  (Read 40705 times)

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Offline max666

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Re: EEVblog #576 - Advantest R6142 Current Voltage Generator
« Reply #50 on: September 16, 2017, 08:29:56 pm »
Have we had a teardown of this lovely piece of test equipment yet?  Have I missed it?

Bump!
Please do a teardown of this beauty, Dave. I think you've teased us long enough.
 

Offline fiddleback

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Re: EEVblog #576 - Advantest R6142 Current Voltage Generator
« Reply #51 on: September 21, 2019, 04:42:49 am »
I recently purchased an Advantest R6142, and, having played with it a bit, would like to share what I’ve found.

First of all, the R6142 is, despite appearances, a complete redesign of the older Takada/Advantest TR6142. The board layouts have completely changed, the TR6142 twiddle pots have been replaced with software calibration, and even the reference voltage has been changed. This isn’t to say that the TR6142 documentation is useless. It provided complete schematics and a very detailed theory of operation, both of which the newer R6142 documentation omit. I suspect that there are enough similarities that older “TR” documentation can provide insight into how the newer R6142 works.

(BTW, one lonely pot DOES remain in the R6142 – I think it’s the equivalent of the TR’s R80, which provides linearity correction “by correcting the time constant errors caused by the turn-on and turn-off resistances” of the transistors used to implement the voltage-generating duty cycle. I haven’t had the guts to play with this, since I really don’t know how to measure its effects, and the manual doesn’t provide a procedure.)

I heard it is possible to hack R6142 into a R6144 by shorting JP1, JP2 and JP11.

Thanks for the tip, baoshi! It is indeed true – all you need to do is wave your soldering iron over the R6142, and it will magically turn into an R6144!! (Well, the front panel labels won’t change, but functionally, it literally BECOMES a 6144, and even identifies itself as such while powering on!)

Initially curious about this ‘upgrade’, I noticed that there were two characteristics of the two models that lent credence to the rumor – 1) the parts lists for both units were (so far as I could tell) absolutely identical, and 2) the specifications (accuracy, tempco, etc) for the two units are absolutely identical. The only difference is that the R6144 extends the voltage range from 16 to 32 volts, and extends the current range from 120ma to 160ma. These differences seem hardly sufficient to justify a completely different model and design, especially given the identical performance.

The R6142 comes with U shaped jumpers installed for JP1, JP2, and JP11. But they are cut! So I’m guessing that all of the units are built and originally tested as R6144’s, but then downgraded to R6142’s by cutting the jumpers. (If I remember correctly, one of them was on the digital board – probably something that the CPU can read to determine personality, and the others were near voltage sources – possibly to raise the upper limit of operating voltages/currents.) Here are the jumper locations (in Japanese). http://bbs.38hot.net/thread-15339-1-1.html

In playing with the R6142 (prior to its promotion to 6144), I came across a peculiarity that’s worth knowing about.

The front panel allows simple manual stepping by a fixed amount (1mv in this case) by pressing the appropriate up-arrow key. It also allows for an automated sweep, simply by pressing and holding the same key. While trying this single stepping, the unit generally behaved as expected – press the button once, and the output increased by 1mv. But every once in a while, it curiously jumped by 2mv. Having noticed this, I set up a sweep, and recorded the voltages output.

The charts below show the results over about the first 1000 1mv steps (0n 10 volt range). The first chart shows that, overall the output appears very linear, as expected. The second chart shows the deviation between the expected voltage and the actual output. Clearly, near 0V output, the output is low by about 3mv. But then the output deviation settles into a curious sawtooth pattern. Taking a look at the magnitude of each step (third chart) shows what’s going on. Each voltage step is about 1mv, as expected. But periodically (about every 126 steps) the step size jumps up to 2mv – just for a single step.


This ‘occasional double step’ behavior seems to occur on all voltage ranges. It is presumably due to some occasional ‘catch up’ being done in setting the digital duty-cycle that generates the reference voltage. I didn’t try it in current mode, but suspect it would behave similarly. Having uncovered this behavior, I just thought I'd share it...


 
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Offline taichi

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Re: EEVblog #576 - Advantest R6142 Current Voltage Generator
« Reply #52 on: October 20, 2019, 06:30:07 pm »
I bought a R6144 with Error05 lately. Inside was an exploded battery as the picture attached :'(
 I really recommend people to replace the battery.
I ordered a ER3V battery on AliExpress but it is going to take forever to arrive,  so I replaced it with yet another old salvaged red battery for now.
With some trace repair, and replacing a torn diode, the error is gone and seems working.
 

Offline lern01

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Re: EEVblog #576 - Advantest R6142 Current Voltage Generator
« Reply #53 on: February 23, 2024, 05:10:56 am »
I bought a R6144 with Error05 lately. Inside was an exploded battery as the picture attached :'(
 I really recommend people to replace the battery.
I ordered a ER3V battery on AliExpress but it is going to take forever to arrive,  so I replaced it with yet another old salvaged red battery for now.
With some trace repair, and replacing a torn diode, the error is gone and seems working.

I just purchased an R6142 with error code 04. The battery is normal. Water seems to have entered near the battery, as shown below. After cleaning, it is still the same. Three diodes are OK. Can you help? Thank you so much!
 

Offline HighVoltage

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Re: EEVblog #576 - Advantest R6142 Current Voltage Generator
« Reply #54 on: February 23, 2024, 10:26:54 am »
You need to start with the cleaning process and then see, if there is any damage to the PCB that needs to be fixed.
Replace broken components and go step by step.

Unfortunately we do not have schematics or service manual for this.
There are 3 kinds of people in this world, those who can count and those who can not.
 

Offline taichi

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Re: EEVblog #576 - Advantest R6142 Current Voltage Generator
« Reply #55 on: February 23, 2024, 11:37:35 am »
I had a similarly damaged unit a few years ago. After removing the battery and cleaning both side of the board with IPA, I found multiple corroded surface traces with multimeter. I soldered those damaged trace and it fixed the unit.
 

Offline taichi

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Re: EEVblog #576 - Advantest R6142 Current Voltage Generator
« Reply #56 on: February 23, 2024, 12:53:17 pm »
You need to take the board out and take a look at the back side of the board and the other board below. I'm almost certain that this is battery leakage, but not sure whether it's from the current battery or somebody replaced the battery without cleaning up the mess in the past.
 

Offline lern01

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Re: EEVblog #576 - Advantest R6142 Current Voltage Generator
« Reply #57 on: February 25, 2024, 04:20:57 am »
Thank you very much for the replies from several friends. The PCB board has been cleaned, and the relevant solder joints have been re-soldered. Check the nearby resistors, diodes and transistors, and there are no problems. When the power is not connected, measure U4 pin 1 and there is a voltage of 3.2V. According to the seller, it turned out to be normal, but after being left for a few months, this happened. According to the maintenance manual, Error Code 04 is related to U1 and U5, but no problem was found. At the same time, I followed the troubleshooting process and checked the waveforms and pins of the related IC when short-circuiting and disconnecting U11 pin1 and GND. Voltage changes are normal. Once again, I hope you can give me some advice, thank you very much!
« Last Edit: February 25, 2024, 09:33:32 am by lern01 »
 

Offline taichi

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Re: EEVblog #576 - Advantest R6142 Current Voltage Generator
« Reply #58 on: March 03, 2024, 12:42:45 am »
Have you tried resetting the calibration data? Procedure is written in operation manual. Turn the ext cal switch on the rear panel on, and power on, then press 0.
 I once had this problem and resolved by this procedure even though I forgot the exact error code.
 
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Offline lern01

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Re: EEVblog #576 - Advantest R6142 Current Voltage Generator
« Reply #59 on: March 09, 2024, 01:08:33 pm »
The internal firmware of U5 (AT59C11) is damaged. But don't know which programmer can be used to program it, I have TL866 II Plus programmer. Can I use AT93C06/46 instead?
« Last Edit: March 10, 2024, 09:28:41 am by lern01 »
 

Offline lern01

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Re: EEVblog #576 - Advantest R6142 Current Voltage Generator
« Reply #60 on: March 12, 2024, 03:42:28 am »
Have you tried resetting the calibration data? Procedure is written in operation manual. Turn the ext cal switch on the rear panel on, and power on, then press 0.
 I once had this problem and resolved by this procedure even though I forgot the exact error code.



Thank you very much for your advice, I reprogrammed the AT59C11 with Superpro 500P and it fixed the problem perfectly. thank you!
 


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