1976 Clock

[Dave WM]

decided to tackle a clock I have has a spare, it was not working, uses a hybrid of electronic and mechanical. Replaced the two 10uf caps, left the .22 electro (I do not have one that value handy).

You have to be very very careful about the wire on the pad that is shared by one of the caps and the coil. Anyway the good news is it working fine, the caps were completely open (when testing with a Simpson 260 VOM). I made a video should be up soon will post when done.

[Dave WM]

the part 2 and 3 are also out there showing the working clock.

 

[S30Driver]

Nice job Dave.  I have a few z clocks I might take a look at one day.

Like your quality Simpson vom, I used the same meter years ago at work to set up AGC circuits in cable tv RF amplifiers.

[Dave WM]

yea the Simpson is my go to meter. I also have a nice HP VTVM that I use for HF stuff or where loading is an issue. The HP uses a vacuum tube in the prob for RF probing.

Get yourself some small 10uf radials and the .22 if you are going in there. I kinda started to run out of room with the 35v ones I had on hand, 16v would have fit a lot better.

[monkeyman]

It's a nice feeling when you manage to get something working!

220nF polyester capacitors should be easy to find to replace the 0.22uF electrolytic. I would certainly do that while you have the clock apart. 

And as far as the transistor goes, it might be ok, but I wouldn't trust it. It's a basic npn silicon transistor. I have fixed a few of these clocks now, and I have seen the transistor fail.

 

[wheee!]

Nicely done!

[german240]

I did a similar thing.. transplanted the internals of an old VDO clock (quarz) into the '71 Z clock. It's almost a straight fit! 

 

Edited January 10, 2017 by german240

[hr369]

Very nice conversion. Which car does that VDO come from?

[Dave WM]

On ‎1‎/‎9‎/‎2017 at 7:47 PM, monkeyman said:

It's a nice feeling when you manage to get something working!

220nF polyester capacitors should be easy to find to replace the 0.22uF electrolytic. I would certainly do that while you have the clock apart. 

And as far as the transistor goes, it might be ok, but I wouldn't trust it. It's a basic npn silicon transistor. I have fixed a few of these clocks now, and I have seen the transistor fail.

 

already back together, I like to do things is stages, so far so good, keeping time to the minute over several days. I would replace at least the cap if I was going to put it into service. for now its just a spare.

[zclocks]

Dave,

You got real lucky with just a cap that was bad. In my experience the tran goes bad all the time and the two coils do drift to the point that they are not usable. Nice wording on UBER careful when soldering around the coil wires, that can't be stressed enough. They are about 35 gauge and easily to overheat. I haven't seen a Simpson 260 for years and loved the one I had when I was in the service.

Good job!!

Ron

[Dave WM]

if you like the Simpson I bet you would love the HP410 VTVM.

 

[Dave WM]

That HP has a regulated power supply and is SUPER accurate on the voltage scales, once its been calibrated anyway.