LQ084V1DG21 LED backlight
Facing a few instruments with a dim backlight in the LCD display, I decided it was time to get rid of the aged CCFLs and replace them with white LEDS. I discovered a few of the instruments I needed to upgrade (Lecroy WaveRunner oscilloscope, Rohde & Schwarz CMU200, Agilent 8753ES) used the same Sharp LQ084V1DG21 […]
New LCD for the HP 8904A
The HP 8904 is a nice instrument and I was lucky to get a cheap one and repair it. But as expected in instruments of this age, the EL backlight panel behind the display gets very dim and reading the screen gets difficult (actually, I wonder if this particular display had good contrast even when […]
Morion MV89A Oscillator Repair
While testing three Morion MV89A oscillators I got from eBay, I found that one of them had a weak output After carefully opening the case with a small propane torch, it did not take long to find the problem while tracing the output circuit. The very first component found, a capacitor, was blocking the signal. […]
iPod Nano 6th Generation Stuck Buttons
We bought a little nice red sixth-generation iPod Nano to my sister Elvira as a Christmas present. Two months later, the power button got stuck and it was no longer possible to turn it on or off. She discovered that plugging in to the USB cable would wake the iPod up so it could be […]
HP Sticky Buttons
Some of the 80’s HP/Agilent Test equipment uses this pushbutton switches (HP P/N 5060-9436), which may get quite hard to push, with a nasty feeling of being stuck and then released with a loud sound, like those clickers used to train dogs. I happen to have a few instruments with the same hard-to-press buttons, such […]
Yaesu FT857 Repair
I got a cheap, known-to-be-non-working, Yaesu FT857 that refused to turn on. There was no sing of life when pushing the power-on button, nothing. It did not take very long to find that the magic smoke inside two tiny parts was forced out to the outside world… Once found in the schematic, it was clear […]
HP 8904A Repairs
I got a supposed-to-be-working HP 8904A Synthesized AF generator which passed self tests and had no obvious problems, so I took the time neccesary to carefully clean it before doing further tests. After hooking it to the scope, surprise… Sample & Hold Amplifier Lower half of the output waveform was not as wide as the […]