Monthly Archives: March 2013

Fluke 23-III DMM Repair

Posted on March 24, 2013 by modemhead

The first two generations of the popular 70-series Fluke handheld DMMs included the 21 and 23 models, which were the same as the 75 and 77 respectively, except their cases were safety yellow instead of the usual dark gray.  The … Continue reading →

Posted in Repair | Tagged , , , | 12 Comments

Beckman Industrial HD140 Multimeter

Posted on March 16, 2013 by modemhead

The HD140 digital multimeter from Beckman Industrial is another in the “heavy-duty” series, very similar to the HD110 in a previous article.  Unlike the HD110 however, this is a 20,000-count 4½ digit model with RMS-responding AC capability. Unfortunately I can … Continue reading →

Posted in Repair, Teardown | Tagged , | 16 Comments

HP 3468A Battery Replacement

Posted on March 7, 2013 by modemhead

The HP 3468A multimeter repaired in the last post uses something called “closed-case” or software calibration.  Instead of making physical adjustments to controls inside, calibration involves applying known reference levels and having the meter store calibration constants.  These are essentially … Continue reading →

Posted in How-To, Repair | Tagged , | 23 Comments