1938 Buick Clock Repair

[LAS VEGAS DAVE]

We drive our car almost every day. Usually only about ten or twenty miles but at least three times a week. This last two weeks were not typical as usually there are no problems. In the beginning of the first week the clock quit once again. In the middle of the next week the radio quit. At the end of the last week the front passenger brake started to grab very hard. I have many 38 clocks and have never had any problems getting the clock mechanism  itself to work. Usually just cleaning and oiling are all that is needed. I can't say the same about the electro magnet winding part of the clocks. The points are old and have arced so many times the original coating is gone and the coils are old and they go bad. Out of four clocks all have worked for me for a limited time and then fail. Usually filing the points get it working again for a while or resoldering a wire that seems to let go on the coil whenever the coil gets hot. I found a source for a limited supply of new coils and points and am having the clocks restored. The first one just came back to me and is working great. The radio has worked for a year but now something in it causes the fuse to blow as soon as the power wire is hooked up, the radio can be OFF and the power wire is still a direct short. I took it out and thought it would be an easy fix but not so. I finally gave up and sent the radio out for a complete restoration, they say about six or eight weeks turn around. I sent two of them so that I will have a spare. I pulled the front drum on the passenger side this morning and it seems the shoes are the original ones. Wheel bearing grease has finally got on the drum and caused it to become sticky and make the shoe not release correctly. I had the same thing happen on the rear when I first got the car but I only replaced the rear shoes on both wheels at that time. I ordered the shoes for the front and should have the brake problem fixed this next week. In the scheme of things these are not big problems, more annoying than anything else. In any event the new paint is holding up well, the engine is running perfect, the overdrive is trouble free and we love our old Buick.

[Daves1940Buick56S]

Dave

As to the clock, I had the same issue with mine - fried contact points. I too tried several things to reconstitute a reliable contact surface but part of the problem is poor engineering by Borg in that the original clock had no good way of suppressing the destructive spark across the contacts as the contacts open and the electric field in the clock coil collapses. That and the folderol related to hooking up the clock after power has been removed caused me to rethink the issue.

 

The attached is what I came up with - a simple timer that winds the clock about every 30 seconds. I did have to make 1 small mod to the clock - I drilled a very small hole on the back and I disconnected one end of the clock coil and ran it outside thru the hole (mind the insulation). I built the circuit on a proto board and mounted it inside a 5"x7" box with wires leading out. Bottom line, it works real good and I never have to worry about disconnecting power, which is good as I have a disconnect switch.

 

Cheers, Dave

ClockTimer.pptx

[LAS VEGAS DAVE]

DAVE I would love to see what you built but I can't open it for some reason. Does it still need the stock coil to work? In my case the stock coils are also not working. I can mimic the points with jumpers but the coils still won't retract the winding arm. By the way I read that same folder and was confused. I just hook the clocks up with the fuse already in them and they seem to work for weeks or months before they fail.

 

Edited November 27, 2016 by LAS VEGAS DAVE
added a sentence (see edit history)

[MCHinson]

Here is his attachment converted to a pdf file so you should be able to open it...

 

 

ClockTimer.pdf

[LAS VEGAS DAVE]

Thanks Matt, it opened but I don't understand what I am looking at. It needs someone that can read these things to understand it. Doesn't the coil in the clock have to work in order for the mechanical arm to be raised in order to wind the clock. Does the device made replace the stock points but somehow make the stock winding arm still raise? Sorry to not be able to understand exactly what is happening here, I am better at mechanical stuff than electric stuff.

[Steve_bigD]

For the clock arcing contact issue simply place a 1N4003 diode or equivalent across the coil which clamps the inductive kickback when the contacts open.  The diode should have the anode connected to the ground side of the coil.

 

Steve D

[Larry Schramm]

Maybe this will help. 

 

The numbers below first number is the part number.  The timer is part number  U1-555.

 

 Sorry about being sideways.

 

clock091.pdf

Edited November 27, 2016 by Larry Schramm (see edit history)

[Daves1940Buick56S]

I guess I should weigh back in here.

 

First, Steve is correct. A diode will do exactly what he says and greatly reduce the self destruction of the contacts. Of course in the 30s and 40s diodes were not available in a small enough form to fit inside the clock, but this problem was well known in other mechanisms and they used a high resistance in place of the diode, usually a small wirewound resistor, to permit the kickback current to flow. Not as good as the diode we would use today but much better than nothing. This was why I was surprised when I originally disassembled the clock. For a few cents Borg could have saved us a lot of grief. For those clocks where the contacts are still serviceable, I highly recommend doing what Steve says - it will greatly extend their life.

 

However, in many cases (like mine), the contacts were fried beyond saving. I first tried just a relay outboard of the clock so the clock contacts would just carry the relay coil current which is much less, but in my case this didn't work either, just too much resistance in the point contacts.

 

So I decided to outboard all functions related to the contacts except the spring tensioning. Originally when the clock contacts closed, a high current went thru the clock coil and kicked back an armature that is connected to one of the contact arms. A spring attached to this armature puts force on a ratcheted gear which tensions the clock movement. As the balance wheel oscillates the gears rotate and turn the clock hands. The armature and contact arm rotates down as the spring detensions and eventually the contacts close, starting the cycle over again. On a properly working clock it will wind itself about every 30 to 45 seconds.

 

So to outboard the contact and timing functions, first I needed to isolate the clock coil electrically. The coil wires can be accessed once the clock back is removed. Once that was done I designed the circuit and tested it. Thanks Larry for expanding on what I did in the drawing, I tend to forget others aren't familiar with reading schematics, my bad. Anyhow, it is designed to pulse the relay about every 30 seconds. The 2.5M pot controls the time interval and the smaller 10k pot controls the winding pulse to make sure the contact arm is thrown back enough. I found that a pulse of about 1/2 of a second was good. The lamps are not required for operation but are good to have if you need to troubleshoot any issues. BTW, if the clock coil is shot this will not work.

 

Almost all of the parts can be obtained at a Radio Shack if you have any near you or ordered from DigiKey. The whole thing fits in a 5x7 box which sits in the glove box. I tell you what, I will see if I can do a more formal writeup with photos like I did on the instruments and post it here.

 

One other thing, I found that the mechanical voltage reg put a bit too much trash on the 6V input and was causing false triggering, so I put a 100 uF capacitor on the 6V line that connects to Vcc of the IC. This fixed it but I haven't had a chance to update the schematic.

 

Cheers, Dave

 

 

 

 

 

Edited November 28, 2016 by Daves1940Buick56S (see edit history)

[DonMicheletti]

Steeve D, 

I like the diode idea, I'm  going to give it a try. Pretty simple fix.

My clock has been running just fine for a very long time, but I know the things can be troublesome. Hopefully adding the diode will put me ahead of the game.

 

Don

[LAS VEGAS DAVE]

Don, if you add the diode to yours PLEASE post a picture or two of it. I also want to do it but a picture is worth a thousand words. I want to be ahead of the game too! Thanks, Dave

[DonMicheletti]

Dave

Will do
 

[LAS VEGAS DAVE]

Cleaned the front brake drums and Installed new front brake shoes today. CAR DOESN'T PULL TO LEFT OR RIGHT AND STOPS GREAT.

[DonMicheletti]

Steve D,

 

I now have the diodes.  Not being electronically inclined, does the silver end go to the + side of the coil?

Boy - those are little!

 

Don

[kgreen]

I have a 60's era car with the same style of self-winding function.  As long as the battery has sufficient charge, the contacts will jump and wind the clock.  If the battery is low on charge, then the contacts will stay in contact and with a small current passing through them, become fried.  

 

Another repair option for the contacts is to cut small sections of RCA pins and solder one to each side of the point base.  The arc passes through the RCA pin sections which are able to handle the load.

 

The over riding tip here is to disconnect the car battery when storing the car for an extended length of time.

Quote

 

 

[Steve_bigD]

Don,

 

The silver band indicates the cathode of the diode so it would be connected to the + side of the coil and the unbanded end to the ground side of the coil.

 

Steve D

[DonMicheletti]

Thanks. Now I'll go to work.  A project for tomorrow.  I'll post photos

[LAS VEGAS DAVE]

Great, I will be looking forward to the photos. Where did you get the diodes? 

[DonMicheletti]

I got the diodes on Amazon. 5 for about $5.  I'll have extras

[DonMicheletti]

I installed the diode. Pretty easy jon (thanks to Steve D). It is a bit fiddly to get the soldering iron into the + terminal. fortunately I have an iron with a small tip.

Here are photos.

A couple of things to keep in mind. Be aware of the points miovement and there is a "pillar" you have to stay away from.

Here is the diode installation. The silver ring goes to the + terminal.

 

The second photo is with the magnet attached to the clockworks

The second photo is with the magnet attached to thye clockworks, note the "pillar" that must not touch the wire.

 

the clock has been running for a while and appers OK.

Sorry for the size of the photos

 

 

 

[LAS VEGAS DAVE]

THANKS DON, The pictures are great. I need to get one or two diodes from you if you have any to spare. I will be glad to pay you.  DAVE ARTHUR,  4141 PIERCE WAY,  LAS VEGAS,  NEVADA,  89110

 

When you say the wire must not touch the pillar do you mean the stock wire that is right next to the pillar that the diode solders to/

[DonMicheletti]

I'll send you one.

The stock wire near the pillar is insulated already. I meant the diode wire must clear the pillar. In the photo you also see an uninsulated wire just above the coil, but that is no where near the pillar.

Since the diode wire is so rigid, I'm not worried about it vibrating into the pillar.

 

The 2 clocks are still running!

The clock in the car has been running continuously since March this year. I was surprised at the pitting I saw already. The clock gains about 5 minutes a month - and that is good enough for me.

The photos are of my backup clock. I wanted to experiment on that first. Since it worked fine I added the diode to the clock in the car too.

Now I'll have to go back and treat the Roadmaster clock to the diode treatment too.

[LAS VEGAS DAVE]

DON THOSE ARE GREAT PICTURES AND I UNDER STAND NOW. THANKS AGAIN.

[kgreen]

This is great info.  Can the title to this thread be changed somehow to make future searches for this helpful tip easier to find?

[MCHinson]

On 12/2/2016 at 6:32 AM, sixseven said:

This is great info.  Can the title to this thread be changed somehow to make future searches for this helpful tip easier to find?

 

If it is OK with Dave, I could change the title to 1938 Buick Clock Repair or something similar.

 

 

[MCHinson]

13 hours ago, DonMicheletti said:

 

The clock in the car has been running continuously since March this year. I was surprised at the pitting I saw already. The clock gains about 5 minutes a month - and that is good enough for me.

The photos are of my backup clock. I wanted to experiment on that first. Since it worked fine I added the diode to the clock in the car too.

 

 

Don,

 

If you would like to write up and send me a technical tip article on this I would love to publish your article and photos in the Torque Tube II. 

[DonMicheletti]

OK, I'll write something up and send it.

[MCHinson]

Thanks. It looks good. It should be in the January/February Issue of the Torque Tube II.

[LAS VEGAS DAVE]

23 hours ago, MCHinson said:

 

If it is OK with Dave, I could change the title to 1938 Buick Clock Repair or something similar.

 

 

Go ahead and change it if you want, its fine with me.