Recently I met with one problem with capaitor discharge failure. Please refer attachment.
This failured was occured intermittently, while failure happened, after restart and reboot testhead,
capacitor can be discharged successfully at the end of the test and showed passed.
Please take note that there was no failure in autiadjust and full system diagnostics.
Did your guys have any idea how to solve above problem detected?
The discharge routine regards C72 C73 and C74 was shown as below
! Capacitor "c69 100n" is in parallel with:
! "c72 33.0u"
! "c73 33.0u"
! "c74 33.0u"
! Maximum capacitance = 119u; damage voltage = 1.834v
clear connect l to "PS3_3_GND"
connect g to "VPWR+"
discharge "CD17", entry 1.83, exit 0.05
And testplan regards dps was shown as below:
dps 1 |dps 2 |dps 3 | wait 300m
sps 4,18.00,1.00;optimize | wait 400m
rps 4, V, A|print tab(10);chr$(27)&"&v3S"&"PS3:+18.0V",V,A
print tab(10);chr$(27)&"&v3S"&"=====>> c72, c73, c74"
print| wait 100m
test"analog/18v" | print tab(10);"analog/18v";dutfailed
wait 100m | dps1 | dps 2 |dps 3 |dps 4 | wait 100m
unpowered | wait 100m
call Shorts (Failed_In_Shorts, Mode$ & ShortsMsg$)
Wait timing I have changed to 2 secs the result still the same. So what I guess not the wait time problem.
In the discharge file, this is not the source if the issue - the failure is from the sps, current supply section in the testplan.
This is a specific failure inside the testplan routine.
the routine is disconnecting the power supplies not used, and then uses supply 4 to set at 18 Volts - and then measures for this 18V in the 'analog/18V' - inside that test, will probably be the VPWR+ node.
so i would first find out exactly which part of the rotuine is causing the problem, is it at the first dps, or second dps after the tests.
i always use the pause and print statement , so add something like, print "debug cap1" | pause after the cps statment and then you can execute through each line by line, and then you should find the error line.
If it is the second dps, then you have issue with too much current being stored -
if it is the first dps, then did this tets work in the past and just stop owrking? then maybe you have a real defect, or something changed on the board to make this part fail
so it seems that it is the case that after the 18V test is finished, then trying to disconnect there is still current flowing.
I am also assume there is no hardware issue with the power supply - , if you ever like to check you can run diagnostics and do a specific test of the power supply in the 'support bay' section of diagnostics.
one other think to point out
this line here already disconnected power supplies 1 , 2 and 3 <<<<<dps 1 |dps 2 |dps 3 | wait 300m
and you are disconnecting again supplies 1, 2 and 3, there is no need to do this<<<< wait 100m | dps1 | dps 2 |dps 3 |dps 4 | wait 100m
I recommend you try to change
change from >>>>wait 100m | dps1 | dps 2 |dps 3 |dps 4 | wait 100m
Change to >>>>wait 100m | dps | wait 100m
of course just the text, not the >>>
if this still doesnt work then seems you have too much current flowing afer the test is completed and you will need to add a small resistor in the power supply line (maybe 10 ohms) and use a scope to measure how long it takes for current to die away, and change wait time accordingly - or use resistors and relay to help discharge the large capacitors on this net
Recently I have met one problem, "Critical testhead alarm" always pop out. It was belong to Unix controller version B3.80.
I have checked all the MPU don't have problem. Clamp shell power supply's fan not turning, after replaced a new one problem still there.
Hi David, this sounds like could be also caused by hardware failure - or over temperature issue
please check all blowers/fans are working on each module - also make sure the filetrs are clean, check the MPU fans are working OK (not stuck) and check fans on DUT power supply are OK
how hot is your factory ?
as this seems to be a problem with the test system, do you have a support representative you can contact within Agilent ? if you let me know your details, i can send contact information to you privately
I've run autoadjust all and full diagnostisc, besides marginal failure regards close relay test, DUT power supplies lead resistance and Mint pint failure,
result didn't show any failures related to testhead critical alarm. So I think should be no problem.
There was 1 factory that share many of testers, only this testers frequently appear testhead critical alarm, others testers don't have. Feedback from
their support team, they said they just run testing the PCB boards, after few hours, the symptoms like hang and "testhead critical alarm appear" simultaneously.
I'm region in Malaysian state of Johor. I already consult my representative engineer, his advise was checked all the cabling make don't have damaged.