Clock problems

[PeterG]

I have a friend who has an 82 380 SL that needs a clock. Does anyone have a used clock /tach he could purchase? Someone also told me to get the speedo/tach cluster out, you have to drop the steering wheel column. Tell me this is not true.

PeterG

[ljmauricio]

Go to http://instrument.articles.mbz.org/renew/ . The article is applicable to 107's also. It will explain how to repair the clock using Radio Shack parts. Haven't done it myself but looks straightforward. I believe the steering wheel needs to be removed to get the instrument cluster out, but it's just one bolt. Simple enough.

[PeterG]

ljmauricio,
Thanks for the wealth of information.

PeterG

[Strife]

This just happened to me (maybe the higher temps recently got to it). These instructions:

http://instrument.articles.mbz.org/renew/

are very good, but a few extra notes:

1. Removing the solder from the grounding point is a little tricky, because it takes quite a bit of heat to melt it. This is because the brass and the entire rest of the back of the panel acts as a heat sink. A $4.00 Radio Shack soldering iron might work better here than my $100+ iron. It is also recommended to use a solder sucker on this point. A solder wick (another method of solder removal) will make additional demands for heat from your iron. As an act of desparation, you might consider cutting the brass at the thin tabs and then resoldering to it, but this woudn't be as mechanically stable and might someday vibrate loose - solder isn't very strong. Bottom line, get the solder sucker.

2. Don't forget the rubber behind the PCB. I don't think this is for insulation as much as it is for vibration protection.

3. Don't forget to check the hands when you put the pointers back on! That is, at X:00, the hour pointer should point right in the middle of an hour numeral. Silly mistake, but you don't want to install the whole thing just to find out that you screwed up (I almost did).

4. If you want to make certain that your clock will work when you are finished, you can take a 9 volt battery and connect the POSITIVE to the tab that sticks out from the back (where the connector to +12 clock power goes, twist a wire onto it), and the NEGATIVE to the grounding point that you had desoldered (tack a wire on to it). Do not reverse the polarity, this will probably destroy the clock. But a 9V battery will make it work and if your hearing is reasonably good you should be able to hear it. You can watch it for a while and see the gears move.

I have some extra clock mechanisms from various 1980 dashboards (which I had disassembled and refinished in burl). Other than going to a smaller crystal package and a slightly different plastic, I didn't see a difference between the mech I removed from a diesel and the 107's clock mech (the diesel one is actually now in my car). If anyone has a broken clock and can get to it but doesn't want to get involved in soldering the PCB, let me know, and I can probably exchange it at a reasonable price (but keep in mind that you still have to solder to disconnect and reconnect the grounding point).