Thread: Capacitor failed to discharged

Hi David,

there seems to be a custom discharge message, because this error is related to power supply disconnection.

could be that you have some large caps , and there is something 'custom' during the power off routine to discharge these caps.

if you search for dps in the tetsplan, that should give more clues as to what is happening ,

my guess would be that there are large caps , C72 etc.. and they are not having enough time to be discharged

Hi David,

let me explain what is going on.

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

Hi David,

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

cps

sps 4,18.00,1.00;optimize | wait 400m
rps 4, V, A|print tab(10);chr$(27)&"&v3S"&"PS3:+18.0V",V,A
print
print tab(10);chr$(27)&"&v3S"&"=====>> c72, c73, c74"
print| wait 100m

test"analog/18v" | print tab(10);"analog/18v";dutfailed

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

hope this works

Hi David, you can use dps 4, or dps

dps statement disconnects all power supplies, dpos 'x' will disconnect a specific supply

seeing as you only have ps4 active, dps 4 will be enough

if you are still having problem, then too much current is still an issue and you need to look deeper into reasons why there is current flowing

you an try to switch the voltage off after the analog tests to give more time for capacitor charge to die down - so try this >>>

test"analog/18v" | print tab(10);"analog/18v";dutfailed
sps 4,0.00,1.00;optimize | wait 400m !switch ps4 to zero volts
dps 4 | wait 100m

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

thanks, Jon

Hi David,

this type of problem can have a few causes, you have to see what else is reported - could be related to temperature, or occur when doing a certain task,

i suggest you run a full diagnostics and if you get any failures, analyse the dgn.log file

which region are you in ? do you have contact info for agilent support?

Hi David,

then all i can recommend is that you change both MPU (assume is a 2 module system ?)

also check that the testhead LAN section is ok, power supply to hub is OK

thanks