Sebastian Harnisch
Electronics Blog
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Technics SU-VX 700: Teardown & Service
The Technics SU-VX 700 is an integrated audio amplifier from the early nineties. It delivers 2x 90W into 8 Ohms and is specified with a THD of 0.007% (20Hz .. 20kHz, rated power). In my opinion it is one of the better Technics amplifiers. Whereas the sound of an amp is always subjective to a…
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Agilent 66309D: Repair
A few days ago I got my hands on a faulty Agilent 66309D Mobile Communication DC Source. To be honest, I don’t think I need it, but it was pretty cheap and I was looking for something to either repair or potentially salvage the case of. The Mobile Communication DC Source is a specialized power…
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Logitech M310: Mouse Button Repair
For some time it became more and more difficult to get a click out of the mouse wheel switch of my old Logitech M310 mouse – inconvenient in programs like KiCAD. I also have a newer and “better” M705 mouse, however, using this one seemed to increase fatigue compared with the old M310. The mouse…
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HP Instrument feet
Many older HP/Agilent instrument share a similar feet design. There are at least two different types though: One with a metal part to prop up the instrument and one without it that can be used on all four corners. The feet can be detached from the instrument, e. g. for use in 19″ racks. This…
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Agilent 34401A: Repair
The other day I noticed an issue with one of my Agilent 34401A’s: I measured a constant DC voltage and after a few minutes the measured value would start dropping and become unstable. Then I got curious and checked the two-wire resistance mode. Same story, maybe worse. A word of caution: High voltages found inside…
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HP 5328B Universal Counter: Mini Repair
The HP 5328 series counters are a range of 0 to 100 MHz Universal counter from the 70’s. While fairly similar on the outside, internally the updated B model differs from the A model significantly. The HP 5328B’s build quality impresses still today – even for the front panel they didn’t use plastic back then.…
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Fluke 175: Repair
I recently scored two Fluke 175 multimeters that were sold on ebay as a set waiting for repair. According to the seller, the first multimeter was fully functional except for the beeper. The second meter had a strange error rendering it unusable, but came with a working beeper. The sellers suggestion then was to transfer…