Keithley 2000 pass self test and no value displayed ...

[Overspeed]

Hello

I have a 2000 in good shape and the PCB is perfect no burn no corrosion ..

I power it on . have a bip pass self test ( full display + rev A1 / A2 )

And after it display mV with nothing as value , when I try to switch to current or resistance  but again no zero or value displayed nothing and no other other function that work only one time and after the keyboard is stuck

Does someone know what is the failure / problem

Thanks in advance

Regards
OS

[ApertureScience]

I encountered this issue with only blank lines appearing on the screen. For me the reference circuit was not working, because the TF-245 resistor network had failed. With no reference, or at least wildly out of spec, the adc did not respond to the processor, thus no digits. Check the optocouplers for communication.

[BennoG]

the 2000 has a full self test. First press the shift key and then press the test key.
Choose full test.
Half way you will be asked to short all the pins.
and later on the high and current input.
Tell us the error numbers you get.

Benno

[Overspeed]

Benno

I have run the self test

I have fault on 100.2 200.2 201 201.1 202 300 300.1 301 301.2 302 303 303.2 403 403.2
with the 4 wire connected fault on 500 500 .1
with the Hi input connected fault 600 600.1 600.2 601 601.2

and the last message FAIL 100.1

Regards
OS

[gamalot]

Is it possible that it is in external trigger mode? I don’t remember if the K2000 can be set to restore to the last state when it is powered on.

Check if there is a "TRIG" sign in the lower left corner of the display.

[Overspeed]

Hello

no I have no sign on ext trigger on the display

Regards
OS

[Overspeed]

Hello

Following Keithley manual 100.1 is ADC fail , sound logical is ADC is no in order all other faults fall in cascade

Now the question is what is the root cause of the 100.1 ?

I have check the resistance value of my tf-245 not wonderfull

1 to 16 = 970
2 to 15 = 180K !!!!


Regards
OS

[voltsandjolts]

Maybe:

https://www.eevblog.com/forum/repair/need-help-repair-keithley-2000/msg1376921/#msg1376921

[Overspeed]

Hello

Following the link provided


Offline f14Topic starter
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Re: Need help repair Keithley 2000
« Reply #13 on: December 17, 2017, 03:34:19 am »
Say ThanksReplyQuote
New update. After remove  U133 (DG444DY) but i dont have this ic. So i replace by ADG412 (i know nothing change if add this ic  )from 34405a board. And self test 100.x and 200.x is pass. So i think problem is there.
now i order new dg444dy for replace
« Last Edit: December 17, 2017, 03:36:50 am by f14 »

DG444 is 2 USD IC so not a big deal to change it I will order some

Regards
OS