Need Help for Backup Calibration Data Keithley 2015

[letron77]

Hello everyone

I am trying to fix a 2015 Kiethley that is stuck.
Its display reads "No comm link"

Before any intervention I decide to save the firmware and files of setting
I have already read several post very interesting on this site

I bought a TLC866 II
It allowed me to back up ODD and EVEN firmware

By cons I do not know how to save the data "instrument setup and calibration constant" which is on the eeprom 24lc16b (U136)

on this page it is about the parametric data backup of a k-2001 by realizing a "DIY I2C dongle" to connect to the TLC866:

  https://www.eevblog.com/forum/testgear/restoration-glory-of-keithley-2001-dmm/msg384347/#msg384347

Can someone tell me how to realize it?
Is the procedure the same on a 2001 and 2015?
Should it desolder 24lc16B?

in advance thank you for your help

Alain

[MadTux]

Should be a similar procedure. I would avoid soldering, whenever possible (due to cleaning the board from flux).
It's important to dump calibration data before playing with different firmware versions, otherwise it will soon display "Error" on display. Happened to two broken K2015 that I repaired. K2015 is a pain to calibrate, because of all the features like AC current

[letron77]

thanks for these tips

But I just realized that the welded eeprom U136 (24LC16B) is very very small and does not allow to fix contact clamps on these pins.
It is much smaller than the eeprom X24C16P which is in the K-2001 and on which we can fix clamps!
Do you even have a solution to advise me in order to save the configuration information on this chip?

From Service manual :
Semi-permanent storage facilities include NVRAM U136. This IC stores such information as instrument setup and calibration constants. Data transmission from this device is done in a serial fashion.

[MadTux]

Perhaps such a clip?
https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2334524.m570.l1311.R1.TR11.TRC1.A0.H0.Xsoic8.TRS0&_nkw=soic+8+clip&_sacat=0&LH_TitleDesc=0&_osacat=0&_odkw=so+8

[letron77]

Thanks - I have just by one
I resumed contact when I would have received

[picburner]

You don't have the space to insert that big soic8 adapter, you have a big capacitor on the side.
To backup my k2010 eeprom I used three adapters like the ones in the picture.
You just have to connect gnd, sck and sda only and not connect the 5Vcc (pin8 eeprom) to the programmer!
You also need to keep the cpu reset to gnd and turn on the dmm (the programmer could never supply the 5Vcc to the whole digital part of the dmm!).

[letron77]

I understand when you talk about connections gnd, sck and sda

However, I do not understand when you say:

        "You also need to keep the cpu reset to gnd"
        (Should it short circuit some of the CPU's legs)

and what is "DMM"?

[picburner]

In practice you have to do the same thing as TiN did, as in the pic you linked in the first post, you have to make a connection between "Digital Ground" and "Reset". You have to find these references in your Keithley 2015 because in Keithley 2001 and Keithley 2010 they are in different places.
DMM = Digital Multi Meter (Your Keithley 2015...)

TP106 could be "Digital Ground" but you have to check if it is connected to pin4 of U136.

[letron77]

Ok for these clarifications
I'm going to look at DMM's SM to find the earth contacts
However I will have to wait for the delivery of the adapter to connect to the chip because no clips can connect to these pins

[picburner]

With the right grabber clips there is no problem to make the connection, look at my pics.
In the meantime I think I found the "Reset": it is near U167.
In fact U167 is a MAX809 (pin2 = /Reset).
Check that the resistor R334 (on the opposite side to U167) is connected to pin48 of cpu MC68306, if it is true this is the "Reset" to use.

[letron77]

it's very nice of you to have taken time to make these photos and explanations!

Can you give me the references of your grabber clips because mine are too big. I will buy the same tomorrow.

To verify this:
"Check that the resistor R334 (on the opposite side to U167) is connected to MC68306, if it is true this is the" Reset "to use."
Can I use a Ohm meter?

[letron77]

I used an ohm meter
That's what I already found as contact between the terminal of the resistor 334 and the legs of the MC68306 cpu.
Is it leg 48 that I indicated?

[picburner]

My grabber clips: EZ-HOOK XKM   Digi-Key code 461-1009-ND (but the Tektronix clips I showed you earlier are also good).

Yes, the pin 48 is the last marked one in your pic (and in my card also there are other pins connected together).
You must connect the reset to gnd so that, when you turn on the dmm, the cpu will not interfere with the TL866.

[picburner]

I forgot one important thing: check that 5Vcc is present at the U144 voltage regulator output, otherwise it is not possible to read the eeprom on board.
Since "No Comm Link" indicates a malfunction of the digital part of the dmm it is better to check that at least the power supply is present!

[letron77]

Ok, I am going to control the voltage of u144

However if I understand correctly I must connect the pin "reset" of R334 (which you have indicated on a previous photos) on the chassis of the device (the ground)

[letron77]

u144 power supply is présent (4.91 v)

[picburner]

However if I understand correctly I must connect the pin "reset" of R334 (which you have indicated on a previous photos) on the chassis of the device (the ground)

Yes and even the instrument chassis is fine as digital ground.

[letron77]

well taken note
I'll wait to receive my grabber clips I think at the end of the week and you recontacte when I did my tests again
thank you

[letron77]

Hello,

I received my grabber clips this morning
I connected as shown (see photos)
However I have an error message "Pin Dectect error"
(in principle this PIN is not connected!)

[picburner]

The TLC866 does the test to see if all the pins are connected correctly.
You need to disable this feature, in this case you don't need it.

[picburner]

I looked at the program menu but my programmer is an old TL866 (the previous model of yours) and this feature is not present.
So I can't tell you how to disable the pin check.

[letron77]

Hello Picburner

In the software I uncheck the otpion "Pin detect"
after I could perfectly read the eproom!
Thank you for your precious help 

I will be able to dismount it now.
Indeed, every time I turn it on it tells me "no comm link"
If you were in my place by what control would you start?

[picburner]

As I mentioned earlier "No Comm Link" is generated by the display/keyboard controller when it fails to communicate with the MC68306 CPU.
So it's in the area around this cpu that you have to look.
Check that Y101 (should be 16MHz) works, if you have an scope check if there are signals on the pins /CS of the eprom and sram.
On the TiN website (xdevs.com) you can find the Keithley 2000 schematics which, at least in the digital section, is very similar to your 2015.
If you can shot some pics of the instrument logic section and power supply so I can tell you if I see any anomalies.

[letron77]

The frequency of Y101 is 14.75 Mz (Only the connection at the top left, for the other 3 connections the frequency is at 0 Mz)
Can you give me the reference of the Eprom and Sram that I have to test?

[picburner]

yes, you're right the frequency of y101 is 14.75MHz so that's fine.
If you can shot a picture of your instrument pcb so I can tell you where to look for.
The pictures you've taken before are too localized and the others are hidden by the TLC866...
I don't have a Keithley 2015 but I have one 2001 and one 2010 so the my references are different.