Repairing GTS clock

**Absinth** · 08-04-2011, 12:16 AM

I am looking forward to seeing if changing out the 3 resistors, 3 capacitors and transistor fix it. Did you get a new coil as well as these can be a problem if they are overheated or burnt out. I have all the bits, just haven't had the time to do it.

Only thing is, I swapped a working clocks PC board into a non working clock and it didn't fix it.... the PC board components may be on their way out but still run a slightly weaker clock mechanism.

The clock mechanisms seem to work fine so it has to be the electronic part that fails.

**HK1837** · 08-04-2011, 07:28 AM

Have a look here. There are also links at the bottom too.

http://holdenpaedia.oldholden.com/Clocks

**wbute** · 08-04-2011, 07:58 AM

Absinth, I did not get a coil and it looks as though it would be the most difficult bit on the board to replace, so that is a last resort at this stage. I replaced the two larger caps last night and will get back onto it when the rest of the bits arrive.

Replacing the board with one that works and still having no luck does not make me too confident, but lets hope.

Thanks for the links Byron, I reckon that a RAAF tech and me would be close to the same skill levels...... not

**wbute** · 17-04-2011, 07:58 AM

OK. Replaced the 3 Capacitors last night. Put it back together and wired it up to a uhf base station transfromer........ and the tuning fork now hums away but it wont drive the the gear for some reason. Will try a few more things and see how I go.

They are called a tuning fork mechanism. They were designed in the 40's by an English clock making company. JECO of Japan built them and they supplied Smiths with the same mechanism for their clocks.

The tuning fork vibrates when the coil is energised which then drives the clock. This is why the clock hums and is also why the clocks do not tick like a conventional clock.

So our true blue Holdens are running a Japanese clock and strangely it is the most unreliable gauge in the dash!

When you pull the adjusting knob it gives the mechanism a helping hand to start, so if you have had the battery out for a while its not a bad idea to give the clock a flick with the adjuster to get it started when you hook it back up.

**wbute** · 17-04-2011, 09:13 AM

Success!!!!!!

Clock two now goes after replacing the caps. Clock one needs further investigation.

**mauser** · 17-04-2011, 09:25 AM

haha well done.... but does it keep time?

Mauser

**wbute** · 17-04-2011, 09:37 AM

I will set it up and run it for a couple of days tonight. Might need a fiddle with the speed adjustment. fingers crossed I suppose.

**jennie285** · 17-04-2011, 09:52 AM

Originally Posted by wbute

Success!!!!!!

Clock two now goes after replacing the caps. Clock one needs further investigation.

Good stuff, I am wondering why ours doesn't hum, and will probably regret saying it didn't after sleeping in the van for 4 days while at Nats, and finding it does...Rodney had the dash out last weekend, and put a little lug on the clock to change the time as all that remained on it was the post which was difficult to get hold of to turn...and yes the way he started the clock back up was to tap it, and turn the hands around, it is still going thankfully.....

**wbute** · 17-04-2011, 11:57 AM

Originally Posted by jennie285

Good stuff, I am wondering why ours doesn't hum, and will probably regret saying it didn't after sleeping in the van for 4 days while at Nats, and finding it does...Rodney had the dash out last weekend, and put a little lug on the clock to change the time as all that remained on it was the post which was difficult to get hold of to turn...and yes the way he started the clock back up was to tap it, and turn the hands around, it is still going thankfully.....

I think some hum louder than others possibly because one of the diodes or capacitors is lightly touching the tuning fork. One of these ones was making a heap of noise and that was why.
The tuning fork makes a high pitched note just like a....... tuning fork! And you really have to put your ear up to the clock to hear it.

The clock in my WB hums like a champion though!

**Absinth** · 17-04-2011, 11:58 AM

Originally Posted by jennie 285

and yes the way he started the clock back up was to tap it, and turn the hands around, it is still going thankfully.....

To re-start the clock after dis-connecting the battery you do a James has said.... pull the adjuster knob out and then let it flick back, there is a bevelled collar on the other end of the shaft that spins the wheel and the tuning fork then takes over.

wb wrote:

OK. Replaced the 3 Capacitors last night. Put it back together and wired it up to a uhf base station transformer........ and the tuning fork now hums away but it wont drive the the gear for some reason. Will try a few more things and see how I go.

That was the problem I found when I changed the PC board from a working clock to a non-working one, the fork hummed but wouldn't keep the clock going..... the only thing I could see that would cause this was either a weak circuit from the old board or the tuning fork is not adjusted properly....

They are frustrating aren't they.... :Chin: