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. […]
KORG Triton CF Upgrade
Tired of floppy and Jazz disks, I looked for a better storage solution to install in the Triton. I tried a Floppy-to-USB emulator and it worked well but the 1.44MB limit was still there. Although a bit more complex, using a SCSI>IDE adaptor and a IDE CF reader looked very well on paper. So I […]
Kenwood TM451 TCXO Upgrade
Being used in a mountain-top repeater, our TM451 transceivers suffered severe frequency shifts as the temperature varied. They are exposed to temperatures as low as -15C in winter and as high as 45C in summer, and the original crystal oscillator is too sensitive to this variations. We measured the repeater to be as high as […]
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 […]
Remote Relay Controller
I reprogrammed the PIC inside the LDG DTS-6R remote antenna switch to control a 8-relay PCB I got from eBay. I built a relay driver that talks to the remote controller via two-wire rs-232 serial interface. It has a programmable default status so the required relay states appear at power-up. DTS-6R Modification I got […]
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 […]
10Mhz GPSDO I (spanish)
Utilizando un receptor GPS con salida de 10KHZ es sencillo crear un PLL que nos permita “disciplinar” un oscilador de 10Mhz. Esta es una manera fácil y barata de disfrutar en casa de una señal patrón de gran precisión, impensable antes de la era GPS. La constante de tiempo del PLL nos permite jugar con […]
CW ID and Telemetry System
We wanted to be able to remotely monitor the operating conditions of the EA4YAF repeater and also provide CW ID. The idea was to transmit a short 1200bps packet with the telemetry information, just after the CW ID, every 10 minutes. This is how the system was designed an built. CW ID CW is generated […]
IF OUT for the TenTec Orion
My friend Angel, EA4CJI, wanted to use a LP-PAN panadapter with his Ten-Tec ORION, which does not have IF OUT port as it comes from the factory, and he asked me to do the modification. You should take a look at his guide if you are working on this modification. The connection to the IF […]
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 […]