Sunday, 19 February 2012

Drying out - repairing a pocket pod

Over Christmas my Pocket Pod died. I'd been visiting my parents and noticed this when packing up to leave. Some of my things, including pod were sitting in a mysterious liquid and I wasn't very surprised to see that when I plugged it in it didn't turn on.

My first thought was that this slightly brown stuff had come from the pod and that the batteries had leaked. However, opening it up the batteries were fine and there was only the tiniest trace of dry brown powder next to the battery compartment. I was briefly hopeful it was okay, but of course it didn't turn on. This was the start of January and I packed it up planning do something about it later. Over a month passes.
I briefly wondered whether a capacitor inside had burst, but this was irrelevant as Line6's warranty for the pod lasts an astonishing 90 days. In any case Line6 service centre never replied to an email asking whether they could accept these for repair (to be fair to them, this isn't like asking if they can repair a valve amp head, but reply to your customers' emails guys). There was only one option left.
  

Cracking the pod
Opening the Pod up is fairly straightforward; remove the four screws and gently prise apart. All the electronics are mounted in the top half-shell, the only connection to the bottom are the wires to the battery compartment. Or, in my case, one of the wires to the battery compartment. And a whole lot of rust-like hard foam. You can see an extra fragment next to the group of four capacitors: this has broken off from around the screw-post.
So, what's happened is apparently that a tiny amount of water has gotten in and happened to do so via the terminals in the battery compartment. These have happily electrolysed and as a result one of the battery connections has essentially dissolved. Messy, but potentially no other damage has been done provided the battery connection can be fixed. But first...
It seems likely now that the original liquid was tea. Coincidentally this is also essential fuel for any electronics project. Just try not to drop it on anything else.
Cleaning up
A bit of cleaning seems appropriate. Mostly done with a paintbrush and dry, though since this stuff was quite stubborn I did wet the brush to try and clean of the last of it. Isopropyl alcohol is probably better if any is available, but I console myself that everything covered in brown has already been wet and unlikely to get any worse. Made sure it was dry before going any further though.
Putting the Rock back
So, at this point I have a problem. The terminal that the positive lead should be connected to is gone. Or, more accurately, was transmuted into the brown mess I've just removed. Looking at the above picture you can see the negative (black) wire is soldered to a tab coming out of the back of the battery compartment, the corresponding tab for the red wire is missing.

A fine Allen key makes a handy lever for removing the remaining part of the battery tab...
...and reveals a very fine hole through which it plugs.

My plan A was to put a wire through and re-solder at both ends. This isn't going to work. The ideal repair would be to have another of these battery tabs to hand, but of course I don't. I have a brief play with tinning some multi-core wire flat to pass through, but soldering it on the other end is tricky. However I do have a few of these:

If life was easy then this spade crimp would fit through that hole and there would be room on the other side to crimp it on the red wire. Of course neither is true. The spade is both too thick and too wide and the crimp section much too long. Fortunately:
  1. I have some pretty heavy cutting pliers.
  2. If you look closely there is a line down the middle of the spade indicating it has been folded to get that thickness.




And with one more trim to straighten it out we have something that will fit. At this stage all that's left is to solder it onto the battery wire and put the battery terminal back over it (both to press it into place and because the stud is needed to make contact with the batteries, bending the improvised tab in place would be more tricky).

Before putting the terminal back on
The last bit of the old tab had to be removed when putting the new one on.
With everything in place, I plug it back in and hope...
So, that's one less distraction from actually playing more guitar.

4 comments:

  1. Thanks, it was a birthday present, so I'd have felt a bit guilty if I'd managed to destroy it within six months.

    Liked your series on drawing trees, difficult because we think we know what they look like and are usually wrong. The observation about the need for shading to show volume is a good one.

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