With origins in what is today modern-day Iraq, the "evil eye" is a paranormal concept where the simple act of looking at something or someone causes a catastrophic event to happen. The look may be driven by greed, envy or simply being a nasty person. There is a long history surrounding the evil eye and it was so feared that merely telling a person that you were calling up the evil eye caused death in that person
As a kid I remember my maternal grandmother (from Calabria) often talked about the "malocchio". Warding off the evil eye had remedies such as throwing salt over your shoulder or spitting in the wind without getting spit on you. There was even a hand gesture using the 1st and 4th finger to ward off the spell. (Is that a predecessor to the Middle Finger?)
Project X VFO Transistor
Well, the malocchio hit the Project X transceiver project yesterday as it stopped receiving or transmitting. The problem was traced to the Local Oscillator (VFO) as right in the middle of listening to a QSO it drifted off into silence.
There is a weight of evidence it was the evil eye, perhaps inflicted by a blog reader who does not like my keeping details about the rig as a mystery. But it sure is not a coincidence that yesterday's posting was about the VFO and then mysteriously it stopped working.
I know it is the VFO as I injected an LO signal from my signal generator into the receiver mixer and Boom! She works which also revealed that the LO level as designed was a bit on the low side. Better receiver performance was found with a bit more juice to the Rx Mixer stage.
Keep in mind whoever did that... an evil eye right back at you.
I will get the VFO fixed, and the transistor used in that part of the circuit is shown in the photo as I have 3 spares. The 2N2672 is sub which I also have. But now we have the real problem.
When I worked for a living, I constantly dealt with DFMA, (designed for manufacturing and assembly). Most of the SSB rigs designed during this time had one focus... small, compact and low profile.
Many were intended for mobile use and if you had a YL in the car it was dangerous to try to tune the rig when the YL's knees were smack dab in the middle of the front panel. Quite obviously she might think you were performing an entirely different action if it were a big box. So, low profile was always good.
Rig designers of this era paid no attention to DFMA and essentially built the rig around critical assemblies. Thus, any maintenance required major disassembly to access that circuit. That is exactly the case with the Project X rig. I will likely have to remove the front panel and do extensive mechanical and electrical deinstallations just to get to the VFO board.
A friend in the early 1960's bought a Lotus Elan sports car. Imagine his surprise, that to change the oil you had to pull the engine. DFMA!
Them that know can make it go!
73's
Pete N6QW