| Electronics > Repair |
| DIY magnetic probe to find a short? |
| << < (4/4) |
| Dachpappe:
Some time ago I found another interesting approach for finding shorts. Louis Rossman describes it in one of his videos: - finding shorts by evaporation of IPA Also I suggest to check the electrolytic caps, especially on the power rail. I had a few ones shorted in old equipment. |
| GreggD:
Answer to Jerome about post (above) by Gregg (me) The schematic is in Orcad Capture V16.6. Been using Orcad for 35 years. A quickie pcb (very rough) just to prototype done in PADS PCB V9.5 Same ~35ish years. The invert/non-invert with synchronous detection is to reject magnetic objects. It works. I tracked a short to under a fpga on a linear motor position sensor board. Would benefit from putting the sensor on a X-Y scanner and scan the side of the board with no parts so as to avoid part height issues. Changes, I am sure I would change something, output to USB so when X-Y scanned you could make an image on a PC. It was posted that a short makes heat. Only if it is a poor short with some ohm(s). Gregg |
| perieanuo:
--- Quote from: systemloc on October 20, 2017, 06:06:03 pm ---Wow, thank you so much for all the really useful replies! Old don: i tried the freeze spray and i tried putting my hand on the board. I put 5amps at 5volts through it and i cant find it! I’m confused as heck at that result... --- End quote --- yep, i used sometimes in laptops motherboard over 10 amps, not a track burnt but the capacitor is found. my boss didn't understood why i asked for 20A psu, after seeing at least 70 euros per motherboard gathered he was bragging all over paris how his tech finds shorted caps. he was too cheap to buy a flir of course, so my last approach was this, and it works. usually 8A is enough, but like your case, 5A reveals nothing. i applied every time the voltage normally present in that node (most of them were in 19V and 5V lines) so without a flir you can definitely use this, it's tested. never got a pcb-shorting problem in laptop mobos, i see some shorted pcb's where i work now, in automotive br, ovidiu |
| Navigation |
| Message Index |
| Previous page |