Monday, December 12, 2011

Hofner Colorama II restoration project (part 10) - repairing the electronics

Just like everything else on this vintage Hofner Colorama II, the electronics have been treated badly and need some attention. By “badly” I mean that they have been left in a damp or wet environment and the pots are scratchy or cut out completely. The output jack also needs to make better contact.

This can hopefully all be fixed with the help of some electrical contact cleaner, but first I’m going to remove all the parts from the pickguard. This isn’t strictly necessary, but since I’m restoring the whole guitar, and the pickguard also needs attention, this is the route I’m going to take.

Firstly, here’s the whole pickguard/electronics assembly. As mentioned in another post, the beauty of the Colorama is how the entire electronics circuit is attached to the pickguard and can be lifted out in one go:

Here's how it looks from behind:

The knobs are removed, revealing some rather disturbing evidence of damp. Check out that rust!

Rather that turn the whole pot by accident when I’m unscrewing the rusted nuts, I (carefully) grip the underside with some mole grips (vise-grips) and unscrew the nut with a socket wrench:

Once all four pots, the output jack and the pickups (these just push through without any screws to unscrew) are detached, some electrical contact cleaner is squirted into the gaps in the pots. I then move the pot shaft around (like turning the volume up and down repeatedly) a few times to help move the contact cleaner around. I also give the output jack a bit of a clean with the same cleaner:

Incidentally, vintage Hofners are quite hard to date, since the serial numbers are, well, a bit of a mess. You can often date them, however, by their pots. This one, for example, is stamped 250 372. "250" stands for the pot value (250K Ohms) and the "372" stands for the 37th week of 1962 (37=37th week, 2=1962). Remember that this is the date that the pots were made, so it may be a few months before they appear on a guitar. This particular Hofner Colorama II is most likely a 1963 model, so the pot codes would tend to verify this:

The Pickups are also in need of attention. The covers are bulging and the solder holding them to the bases has cracked.

Additionally, one of the pickups has a nasty dent on the top:

And the same pickup is missing one of the tabs that holds it under the pickguard:

The only thing holding the pickups together (apart from the solder) is the pole piece screws. Once removed, the pickup opens easily:

As you can see, these are single coil pickups. Hofner did make humbucking pickups in the same format, but these have “Super” written on the top, just under the diamond logo. I’m not aware of these ever appearing on Coloramas, however.

Here I'm using a small hammer to flatten out the dent on the top of the bridge pickup:

I don't want to go overboard here and I'm happy enough to stop at this point. I'm sure this will polish up nicely:

Both of the pickups were opened, the covers bent back to a non-bulging shape and soldered back on. Additionally, the bridge pickup had a new tab soldered on:

All of the nuts, washers, pointers, etc., were also cleaned with a wire brush:

A lot of elbow grease was required here, especially on the pointers, which all had very deep rust (uncleaned example shown here).

Before putting the electronics back on the pickguard (which, incidentally has been flattened and cleaned up, the details of which will be documented in a future blog post), I've put some metallic tape on the pickguard in order to reduce unwanted electrical interference/noise.

And here's everything back in place:

And the front:

Finally we add the replacement knobs (all sourced from 60s Hofners):


Reslosound said...

Great work your doing here! A nice job.

stu said...

Thanks, Reslosound. Much appreciated.

Les Crompton said...

Just cleaned electrics as you instructed appear to be okay now .Not installed on guitar yet.One bot is dated 228 another 223.strange!I mustcomplement you on your sterling work,you must have the patience of Job.I bought the guitar at auction last week for £120 but commision and couriertotal £189 so not bad really.Frets litte wear but all in all good.No volume pointers dont know if this is significant. Again congrats on your work.Regards Les

stu said...

Hey Les, thanks for your comment.

Those pot numbers do seem a wee bit weird. I wonder if they had the "2" at the beginning instead of at the end in 1962. I wouldn't worry about the pointers, They're not at all necessary.

I'd love to see pics of the guitar if you have a chance to take any (don't feel like you have to wait till it's all back together!)

stu said...

Oh wait, mine are from 1962 too. So maybe EARLIER in 1962 the "2" was at the beginning? Do you have a photo of the pots?