N0ZGO Fights Lightning- and WINS!

Zach, N0ZGO, our roving Dallas/Houston JSCARC ham, kindly gave us permission to upload this on our website after posted on the w5rrr.groups.io reflector.  As a keen practictioner of hands-on radio repairs, this one was particularly impressive for several reasons:

1. Induced lightning damage is usually catastrophic since today’s radios have so many sensitive components within the guts. No matter how well designed radios are, there’s no protections that can preclude the huge forces of an EM pulse into the radio, which finds ways into the radio thru the data lines, antenna ports, power lines, or even switching lines. I usually avoid working on lightning damaged radios, but Zach pulled off a very uncommon accomplishment (and the wee bit of luck that it wasn’t worse). 
2. Skills and a steady hand to work on today’s surface mounted components is still an rare artform.  As you can see in the following photos, Zach really has fine technique doing rework with the SMT device.  Not many foks (like me) have these skills.
3. Lastly, there’s the excitement of hunting down a root cause failure which is terribly fun and rewarding.  Just reading his short story invokes lots of adrenaline to successful find a culprit and bring a dead carcass back to life.  Usually the average ham would relegate this damaged radio to the trashcan.  Zach, you saved another radio life- way to go!

Here’s Zach’s post:

As an indication of how long ago I made my last satellite contact, I just realized that the lightning strike a year or so ago had taken out the RS-232 port on my FT-847.

Armed with schematics, I was able to narrow the failure down to either or both of two chips: Q1130 (MAX232CWE) or Q1107 (BU4053BCF). Unfortunately, both chips are located on the back-side of the AF-CTRL board and required the removal of that board.

Since I had a ST-branded replacement for Q1130 handy, I tried this first. Better — I was getting more than zero volts on the RS-232 TX pin from the rig, but the logic level at R1421, which is the RX input for the rig’s CPU, was only going from 0V to ~1V.

It turns out that Q1107 was also partially fried. Replacing this chip brought the CAT control functionality back to my rig. Huzzah!

 

I then made a contact via RS-44 with KE8RJU this morning. My satellite operating skills need a bit more rust knocked off of them, however. 🙂

See you on the birds!

— Zach
N0ZGO