I've been in Amateur Radio since 1974, and still find new and interesting things to do. I like to build, restore, and operate on the air. This blog has been running for many years, so be sure to check out "Jump to Posts on Specific Topics" in the RH column to drill down and find lots of stuff. Visit www.WB4IUY.net for the lowdown at WB4IUY. Email me at wb4iuy@gmail.com if you have any questions.
This Cobra 2000 was brought to me as a parts rig, when a friend had another I rebuilt for him. I just couldn't bring myself to use it for parts, despite it having been hacked and also missing several things. Additionally, some previous owner was a heavy smoker and it was yellow, inside and out...
I would put it on the bench and work on it until I was tired of it, and put it aside. I finally finished it, and it is a pretty slick radio. Here's some pics, vids, and a little more info...
Cleaning started in the 3 pics above...
One of the front panel controls was busted...
An unstable hack on the 11mhz osc had to come out...
Wires clipped, here and there...
One of the headphone receptacles was jammed back inside, from its mounting location...
Freq counter / clock was non-functional...
Mosfet hack had to go. DC supply was hacked to 16vdc...
Front panel hacks removed and put back original...
Punch list...
Parts cut around the 11mhz master osc...
The 11mhz xtal was off freq, so a circuit was build with temperature stable parts and installed. No more drift...
Found more cut wires...
More cut wires, sheesh....
Hole repaired to reinstall the headphone jack...
Another hack / trimmer to be removed...
Mosfets removed, new bipolar transistors and support components reinstalled.
Freq counter / clock repaired and operational...
Taking shape!
Junk removed from the driver and final stages...
Ribbon cable and switches removed from previous pll mods...
Pllmods mapped and diode matrix designed for proper switching.
Busted ton control removed, PC mount tone pot installed and adjusted to mid-range. 6 position rotary switch installed in old tone control location. This cleanly controls the pll diode matrix.
Switch shaft to be shorted and original knob fitted...
Tone control now controls PLL mods.
Variable power installed and control fitted to rear apron.
Hole plugged with chrome bolt.
More cleaning completed.
Replaced blown power supply pass transistor and hacks removed.
Parts replaced around AM power control circuit...
This cap bumped from 1uf 50v to 22uf 50v for improved PEP in AM.
