This week's test gear repair short story:
Scraped up a Keithley 199 System DMM (without the scanner board) for $50 plus shipping. Not in great shape, but still...
![](https://www.dropbox.com/s/69u2wbme7mg7ted/k199-mess.jpg?dl=1)
"does not power on" ...spin the wheel, roll the dice!
![](https://www.dropbox.com/s/nz9n0qo84ks4jq4/k199-nopow.jpg?dl=1)
Looks nice and clean inside. No obvious destruction.
![](https://www.dropbox.com/s/92k2yv26lcty5wp/k199-inspect.jpg?dl=1)
But turning it over....
![](https://www.dropbox.com/s/hb56cbxl0apft1g/k199-faults.jpg?dl=1)
Looks promising! In a bad, yet good way.
Fix fix...
![](https://www.dropbox.com/s/ik9xobirtlpwgjd/k199-fix.jpg?dl=1)
And a bit of recapping here and there. All of the small electrolytics were reading 5-10 Ohms at a range of frequencies. Dry. The big ones were all ok.
Quick check that things are going to plan...
![](https://www.dropbox.com/s/20cd0kgyf5jjntn/k199-test.jpg?dl=1)
A good clean and reassembly next. Some basic tests for ohms, volts.
![](https://www.dropbox.com/s/uqnyp39uhs2hb65/k199-ok.jpg?dl=1)
Overall, worth the small amount of cost and trouble. And more fun than the other things I had to do today.
A few notes:
The board and pads were damaged by overheating pins, caused by dry solder joints. These pins were badly oxidized and would not take solder. Using flux wasn't enough - I had to grind the sides of the exposed pin. The board in this unit is also very easily damaged by heat and I found acetone quickly strips the green coating from the board so only ISO is safely usable. This all took longer than it really should have and wasn't as tidy as I would have liked. I'll need to look into better ways of recovering oxidized/corroded/burned pins as it has become a bit of a theme in recent repairs. I have been dealing with a Tek 7613 PSU with similar problems on the solder joints of some header pins.