| Electronics > Repair |
| Keithley 2002 repair help |
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| Zucca:
--- Quote from: Dr. Frank on July 19, 2017, 03:02:17 pm ---Suggestion: Never use ultrasonic bath on assembled PCB. This will probably kill many/most of the semiconductors. --- End quote --- Hi Doctor Frank, do you have any example of that? I fully agree with you for MEMS devices... After some googleing: https://electronics.stackexchange.com/questions/196373/components-to-avoid-using-on-an-ultrasonic-cleaner Interesting, did not know that... |
| MadTux:
I would at least be careful with older chips that have unsupported bond wires (the ones with a lid on it and an open air die). I don't know wether gold has an endurance limit, but aluminium doesn't have one, thereby aluminium foil is "eaten" by ultrasonic cleaners https://youtu.be/YR5PgwEDFzs?t=2m20s https://en.wikipedia.org/wiki/Fatigue_limit |
| nikonoid:
That is some fascinating information. I did not expect ultrasonic cleaner to be able to damage the board. Parts should be arriving today. I cannot wait to dig into this new project. Sent from my iPhone using Tapatalk |
| Samogon:
Zucca, From the link you provided --- Quote ---Ultrasonic cleaning is fairly commonly used for cleaning flux from PCBs during the production process. I think you're assuming the wrong reason for their use in your answer. --- End quote --- But k2002 is not where i will use it. And its pcb pretty big Crest ultra sonic cleaner of such size would cost ~$2k |
| nikonoid:
Picked up Keithley 2002 rejected from the calibration lab. They said that it would not hold DC Volts calibration. They gave me printout with DC Volts measurements they did using Fluke 5720 and on my my 10V standard I got the same reading give or take 0.5ppm. So I decided that my standard is not that bad. I did the spot DC calibration myself. The meter asked me for 2V and 20V inputs and also dead short calibration. The short calibration took a very long time. Maybe 20 minutes or so. I did it with fluke's 88X-Short that looks identical to Keithley 8610. When I plug it in value fluctuate between 20nV and 180nV. I hope that is normal. After that spot calibration unit is holding 2v, 20v, and 200v ranges very well (even after power down), so clearly EEPROM works. 200mV range is a bit off (by 10ppm or so) but this is only according to Keithley 2000, so I am not sure is that is an issue. What else could be a reason for meter failing to calibrate at the lab? Should I try comprehensive calibration myself before getting it back to the lab? Thanks. |
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