This week for the first time in over 25 years, I needed to work on the components inside an audio board. I was not prepared for the changes that I faced. I was worried about changes to the circuits on the motherboard but the changes in my vision and a slight shakiness in my hands that were birthday gifts from Mother Nature every year were the unexpected surprise.
My first challenge was just seeing what I was working on. Fortunately there was a pair of old reading glasses around that were strong enough to be used as a jeweler’s loop. Ahh – yes!! I could see well enough. I could even read the circuit diagrams.
I must admit that I dreaded what I was going to find when I disassembled the board. I just knew I was going to find one of those new fangled multi-layer circuit board that can’t be repaired without sophisticated tools. To my pleasant surprise I found an old fashioned two layer circuit board with some of the components surface mounted by a flow solder machine on one side. Halleluiah, the parts I needed to replace were installed using the old fashioned soldering iron method.
This is gonna be easy, I exclaimed as I warmed up my trusty soldering iron and tested my “solder sucker” against my thumb. I started with the two electrical connections on one end of the slide fader. I was gratified when a quick hit of the iron and a slurp of the solder sucker gave me a clean hole with the post of the connection sitting clean in the middle of free space.
Alas, pride goes before a fall. I soon discovered that the years have left my hands a little shakier than back in the day where I could easily thread a needle. Another issue was holding the circuit board steady. I didn’t have a vice suitable for holding the circuit board steady while I worked on it. But some improvisation with jugs of cleaning solution yielded adequate results.
There were only two connections on that side of the fader, but there were four on the other side; two for ground and two for the fader arm. Try as I might, I could not get those clear of solder. So it was time for me to butcher the bad component to remove it. I cut the four connections as far away from the board as possible and was ready to lift the damaged slider away from the board.
“Not so fast!” fate exclaimed. This is too easy. The slider component was stuck firmly to the board and was not going to move anywhere. It was then I realized that the fader was firmly attached to the board with three non current bearing solder joints. It had not even occurred to me that this might have been done. But sure enough, there they were, laughing at me as if to say “gotcha!”
A quick soldering iron and solder sucker attack followed. But I could not prevail against a solder joint that had flowed through the hole and spread out on the other side of the circuit board. I did not want to bring out my bigger iron for fear of damaging the surface mounted components nearby. So I removed the parts inside the component in order to get to the posts directly with the soldering iron.
It was at this point where fate started cackling like the Emperor Palpatine in the Star Wars movies. It seems that today’s solder has a higher tin composition than what I was used to. This gives the solder joint higher corrosion resistances, but raises the melting point. Those remaining posts and connections gave me the good fight but in the end they surrendered and left me with clean holes and no damaged components.
Oh – and they also left me with some minor burns on my fingers. It seems that after a multi decade span of time during which I used my soldering equipment a number of times that can be counted on the fingers of one hand, I had lost the muscle memory awareness that the tip of that tool in my hand was hot enough to melt metal.
Finally the slider was removed and the circuit board cleaned with alcohol and a soft cloth. Now the board sits on my work bench waiting for the replacement parts. I am doing the radio shows that originate from my home studio with my backup board. That is a bit of a challenge because the backup board was not designed for radio and lacks a few broadcast enhancements such as on/off and channel selector switches and tally and studio monitor muting.
Tomorrow morning it will be nice to be in the WUSC-FM studios with a fully functional broadcast audio console. At this point in my life I have discovered that it is easier to rock the oldies than it is to change sliders. Oh MY!
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