OPMI-1 LED Conversion
I was lucky enough to get an old Zeiss OPMI-1 surginal microscope, with very high quality optics. Surgical microscopes differ from conventional ones in that they leave plenty of room between the subject and the microscope to work with hands and tools, which makes them ideal to work in electronics. This particular one worked great […]
HP 8753ES LED Backlight
The 8753ES VNA is a wonderful instrument, but it has many years on its back, and you may find yourself with a barely readable screen due to poor backlight. I have a dedicated article on converting to LED backlight the Sharp LCD module that Agilent used in the 8753ES (Sharp LQ084V1DG21). But in this one, […]
IC-R8500 Low Sensitivity
I was happy with the IC-R8500 until one day I used a splitter to connect another receiver along this one to the same antenna at the same time, and I found it was performing a worse than the other. Moderate signals were readable on both but I could hear clear voices on the other than […]
HP 70004A Repair
I bought this cheap 70004A color display as faulty. I was happy to find it actually worked… or so it did for a few months. One day, it refused to turn on. I could see the power LED flash briefly upon turn-on and then… silence (pretty easy to tell with your eyes closed if this […]
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 […]
IC7100 Dual-head Switch
I needed to operate a single transceiver from two different locations, using two controllers. Having to disconnect the cables was not an option and a simple “Y” would (most probably) damage something. I thought I could build an automatic switch that could change the connection from one controller to the other automatically. With the schematics, […]
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 […]
In-Wall USB Outlet
USB Outlet The kitchen worktop is the ideal place for placing the mobile devices for charging during the night. But we were tired of having to use three diferent chargers, usig three AC outlets, and moving them from the drawer to the wall everyday. I found multi-port USB chargers but I thought, why not having […]
Luxman A383 DAC Upgrade
This old amplifier sounds awesome but I got tired of depending on soundcards or external DAC for the HTPC. A very annoying issue was the loud POP! sound from the IQ7 speakers every time the HTPC went to or came out from sleep. Not wanting any more channels than left+right, I did not want to […]