SWR/PWR meter repair - hold your breath!

 So unfortunate I coincidentally dropped met precious Welz SP-15M SWR/Power meter. From the outside there was no real damage. But unfortunate the meter's pointer wouldn't move when applying power to it. I bought this meter in 2011 on a radio rally and it went with me at several portable occassions. It is a nice and accurate meter excellent for QRP and I don't want to lose it. So searching for a solution I arrived at the TRX lab youtube channel about the repair of a Diamond SX 600. At 4.05 minutes Peter shows a easy way to measure the mechanical voltmeter itself. So, I tried. Between the terminals my meter showed resistance. The meter is not stuck ( you find it on the internet as most common fault). But applying voltage on it with both the multimeter and a 1,5V battery the voltmeter still didn't show any movement. I also measured if the voltage pickup was correct when I was TXing and that showed that there was nothing wrong on that side. Not shure what to do now....I asked Peter and got the answer it could be a mechanical issue. Of course, there are not much electronics in a simple SWR/PWR meter. It consists of some coils, diodes, switches and a voltmeter. What else could it be?

After a good night sleep I was thinking that the fault could only be at the volt meter itself. For that I had to take it out of the housing. First of all I desoldered the wires and the capacitor that was soldered over both terminals, not the easiest job since wires were wrapped around the terminals. After some effort I got the bare meter in my hands and I could finally measure the meter again and.....it showed no resistance this time! To research the fault I had to take it apart. A very delicate job with my thick fingers. But as you can see on the photo I managed it.

Next thing was examine the actual inside for any damage with a magnifier since this is really something small. Luckely my phone has a excellent magnifier as well and I managed to picture the problem.

 Can you spot the problem? It is the small spring which is not connected to the terminal anymore. Remember this is very tiny. Personally I can only see it with a magnifier. To solder it you need a steady hand and hold your breath. At first I soldered it but the spring had moved in a wrong position. At a second attempt I got it right. A quick measurement with the multimeter showed resistance again and I saw the meter move as well. Now it was just a case of rebuild the thing and test it.

A quick test with my CB radio which previously showed that it has 3,5W out . After the repair nothing changed so I guess I don't have to calibrate the meter. Now I really need to be more carefull with my equipment. However it is a miracle this didn't happen before since portable use isn't always the best for this kind of meters. I might search for a digital alternative to bring with me in the field and keep this meter in my shack.