[Johnson] Solid State Power Supply in a Ranger

[Freeberg, Scott (STP)]

I agree with Jerry and others.  I highly recommend replacing the 18K resistor.  It is probably going bad, and if it does, it can take out alot of stuff.  I speak from personal experience.

My Valiant did that.  It uses the same VFO as the Ranger.  It all started out with mystery symptoms.  Every once in a while the fuse would blow.  I couldn't find anything, everything seemed ok, so reluctantly I replaced the fuse.  A few weeks later it did the same thing, resulting in the same fuse replacement.  Sometime later the fuse blew again, I still couldn't find the culprit so I, and I only admit this to make sure you don't do it, put in a slightly higher rated fuse.....  Well the next time it blew, the OA2 was fried, the 6AU6 VFO tube was fried, the LV tube was fried.....  It was only then that I heard about the 18K resistor problem.  Yes it was the 18K resistor and I'm sure my higher rated fuse just accelerated the failure.  I removed the resistor and measured 150 ohms.  

You don't have to move the resistor out of the VFO compartment if you don't want to.  Its strictly a personal thing. Moving it out will result in less heat in the VFO compartment.  I put in a 4 or 5 watt 18K resistor and moved it directly under the VFO compartment.  There is a grommet conveniently located in the VFO compartment, and I used that to pass the two wires out of the VFO compartment and to the 18K resistor.  

Some people I've talked to have had the 18K burnout problem, and some people haven't had any problem.  So its strictly your decision to check it out.  I'm a pretty conservative guy when it comes to changing things out, preferring originality where ever possible.  I'd check this one out.    

73, Scott WA9WFA
http://www.qsl.net/wa9wfa