Does a component-level flying probe exist - Page 1
Forum section: electronics / testgear

author: matviy
author_rank: Newbie
timestamp: September 17, 2019, 01:03:09 am
content: I'm working on finding defects in RMA'd PCB boards. I have the schematics and board views for all boards, and I also have "gold" versions of all the PCB boards.To speed up the process, I would like to have a flying probe that can probe each side of individual components already on the board on (like resistors/capacitors) and measure the resistance to ground. I could do this on the gold boards to find the expected resistance values, save them, and then do it on defective boards to try to narrow down the failing area. This would help speed up my process immensely.Does such a machine exist? I know flying probes exist, but afaik they test pre-defined test points that are made large enough for them, not individual components. I need to probe every component on these boards.

author: tautech
author_rank: Super Contributor
timestamp: September 17, 2019, 01:35:08 am
content: Welcome to the forum.To check ground continuity for both pads in a passive I'd use the cheap SMD tweezers with both tips into one terminal of a DMM and the other DMM lead on circuit ground.Any DMM with an audible Continuity test could be used for this.eBay example:https://www.ebay.com/itm/SMD-Test-Clip-Meter-Probe-Multimeter-Tweezer-for-Resistor-Multimeter-Capacitor/401805580037?hash=item5d8d7a9705:g:klMAAOSwuZ9cRaO-I find SMD Smart tweezers incredibly useful for checking components as it's a one handed operation.There are a couple of good quality brands available that guys that do SMD stuff all recommend.https://www.lcrresearch.com/pro1/http://www.smarttweezers.com/

author: Fire Doger
author_rank: Regular Contributor
timestamp: September 17, 2019, 05:32:56 am
content: Quote from: tautech on September 17, 2019, 01:35:08 amHe is looking for "Flying probe". Good luck testing 2k connections with smd tweezers in exact order and compare them with spreadsheet....

author: nctnico
author_rank: Super Contributor
timestamp: September 17, 2019, 12:13:49 pm
content: Quote from: matviy on September 17, 2019, 01:03:09 amI think this is the wrong approach. From my experience failures often have a limited number of causes. I'd sort the boards based on the type of defect first. If you find the problem on one board, you can do the same repair on all the other boards with the same symptoms. This way you can probably fix 80% to 90% of all the boards quickly. Also do some math on what kind of production failure rate you are looking at. If the failure rate is below 1% it is probably more sensible to just scrap the boards.Testing all components is pretty much useless. Unless components are under a lot of thermal or mechanical stress they are very unlikely to fail.If you have random defects then you are likely dealing with a problem in the production process (most likely soldering or temperature too high). Reflowing the entire board could be a solution if the solder joints are bad but the root cause needs to be fixed as well.

author: ogden
author_rank: Super Contributor
timestamp: September 17, 2019, 12:26:26 pm
content: Quote from: nctnico on September 17, 2019, 12:13:49 pmActually looking for flying probe just to test failed boards does not make any sense. If volume of failed boards is so huge that you need automated testing, then why don't you use same automated testing which you supposedly are using in the manufacturing process? If you manufacture boards w/o flying probe tester then you don't need it to fix them.