53132A counter has INTERP:FAIL (intermittent)

[dl1640]

on self-test or when normal run the 53132A reports INTERP:FAIL, sometimes but not always.

according to the service manual the faulty ASSY will be A1 motherboard or A4 power supply.
power supply is fine and i returned the unit to local Keysight service center after a few days it came with a repair quote to repalce the A1 motherboard

i do not want to replace the board not economic because i rarely use this unit these years and it should not been thru over-stressed or excessive input. maybe humidity?

i hope someone has same experience and knows how to put it back on the track

[gab_au]

Hi,
a few questions first: 1) It's not clear to me from your description, does the fail occur from cold - initial turn on or after it warms up and you manually do a self test from the menu, or both?; and 2) When it fails what happens - does it not count frequency or does it not count interval or both?

If it doesn't count or do interval then I'd check the +/- 7.9V rails in the trigger circuit. If it counts but doesn't do interval then I'd be looking around the ADC/DAC in the interpolation section, I don't believe they're used in the count mode. As you indicate it is intermittent then perhaps it may be a dry joint on one of those IC or maybe tin whiskers around those IC (assuming it's lead free solder).  My tin whisker remedy, and general FOD mitigation, is either an esd brush, or a soft toothbrush, while using a esd wrist strap.

Perhaps others more familiar with the 53132a workings may offer some different advice to get you started?

[dl1640]

thanks for your suggestions.
will try to find more when the phenomenon reoccurs, might be time consuming.

[DaJMasta]

These sort of intermittent failures certainly can be, basically, you want to find a way where you can replicate the failure so you can actually start measuring things and trying to find the cause.  Rather than just having your scope probing things every time you power it up, I'd open it up and start wiggling cables and such - mechanical failures are a pretty common intermittent failure, so a cold solder joint, an oxidized connector, or a damaged cable can sometimes be the culprit - which while it's hard to find, it's often an easy fix.

Good luck!