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 […]
DIY HP-MSIB Cable
HP-MSIB cables, original or third-party, are now difficult to find and frequently for more money than the equipment to which they will be connected. It seems HP used special controlled-impedance cables for their originals, but it turns that for reasonable-length runs, simple 50-pin twisted pair SCSI cable works just fine. This is how I built […]
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. […]
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 […]
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 […]
TEK 5000 modules in TM5000 frame
After getting a cheap PS5010 in good shape from eBay, I needed to make it work on my TM500 mainframe. Since TM500 modules can be used on TM5000 mainframes, I thought the reverse should be also possible. I found some references on the web and newsgroups, but no details on how to do it. Here […]