you can fix your 260Z clock

[monkeyman]

Hi everyone.

This is my first post. I just found this site a couple of days ago and am excited that we have a good Australian forum.

I hope to get some good help from the forums and so thought it might be appropriate to make a contribution first. I saw a post about replacements for the Z clocks, but if you have a 260Z and a bit of electronic knowledge, you can probably get yours working reliably again. I fixed mine (and a couple of others) a few years ago and it is still going strong. I did a nice write-up and posted it on the Classic Zcar Club website (my initial post had an error in it which I fixed a few months ago).

I will post it here so it can hopefully help some of you. (I had to reduce the resolution of the pics a little to fit the attachment requirement, but that has had little overall effect on the document.)

Enjoy.

3910_.pdf

[gav240z]

This is great, and very well detailed and explained. Thanks for taking the time to share with us. I'm sure I'll use it to fix my half working 240z clock .

[zedevan]

yeah looks good, but hopefully my clock will be replaced with a boost gauge so the fact its broken will no longer be an issue!

 

whats your user name on classiczcars?

[monkeyman]

This is great, and very well detailed and explained. Thanks for taking the time to share with us. I'm sure I'll use it to fix my half working 240z clock .

 

Unfortunately, I don't think my write-up will help your 240Z. From what I have seen, the 240Zs had different clocks, made by Jeco. These used a different mechanism internally (a motor actually). It might be possible to put a 260Z clock into the 240Z, but I don't think this would be as simple as just swapping them over. The 240Z clock I played with mounted into the dashboard differently, the mechanics don't match.

[monkeyman]

yeah looks good, but hopefully my clock will be replaced with a boost gauge so the fact its broken will no longer be an issue!

 

whats your user name on classiczcars?

 

I went by 'monkeyman' there aswell.

[gav240z]

Set this topic to sticky. Bumping it up again as a good tutorial on how to fix your 260z clock.

[Clockwork]

Brilliant! +1 to the 260z 

[Andrew_L26]

Hi All, I've just got my board out and I've decided to replace all components on the board as one resistor is giving an open circuit on my multimeter, I assume these resistors are 1/2 Watt each? I'm having trouble sourcing some new capacitors as I can only seem to find ones suited for 16V at the closest (these are rated for 10V) anyone got a good source for these. I think I'll go into jaycar when I get the chance and ask there.

Also I found this transistor online I assume it would be fine even though it has a slightly different code (CR828  R.59 rather then CR828 R.69)

 

One last thing, the issue with my clock was that when I put power to it (9V battery) the motor would just twitch and eventually stop moving, I could get it swinging if I toggled the power on and off. Not sure if anyone knows what that means

 

Thanks for your help with that schematic!

 

 

 

http://www.ebay.com.au/itm/10pcs-2SC828-R-C828-R-C828-100-Genuine-NEW-PANASONIC-TO-92-Transistors-/181183596668?hash=item2a2f62487c

[monkeyman]

You might not find an 850 ohm resistor too easily, but I would be very surprised if 820 ohm wouldn’t do fine. 1/2W each will be fine. Finding caps should be easy. The values used are pretty standard, and it doesn’t matter if you use 16V, 50V or 100V rated ones (though 100V+ electrolytics could get physically large). Use what you can get. Jaycar should have something.

I am amazed you found a C828 transistor! I don’t think I could find one when I went looking (but it was a while ago now). The different code might reference different voltage or current ratings. At the voltages and currents we are operating at, I wouldn’t worry at all.

 

The behaviour you are seeing isn’t too different to what I was seeing. The circuit could get the ‘balance wheel’ moving a little, but not enough to get the clockwork going. Once I fixed up my components, the balance wheel would oscillate a lot more and would keep going.

I never tried testing at 9V. I used a bench top power supply to get my 12V. I’m not sure how effective the circuit would be at 9V. Even with the circuit working, at some lower voltage, the clock will stop working. I don’t know what that voltage is.

 

Since I first posted the repair write-up in 2008, I have never heard if anyone has been able to use it to fix their clock, though i see it has been downloaded many times from here and from classiczcars.com. So if you get it working, let me know.

 

I just downloaded the write-up and see that the oscilloscope waveforms have disappeared. I will see if I can find them and fix it.

 

And for the record, the clock I fixed in 2008 is still in my car and working well.

 

Good luck

[Andrew_L26]

You might not find an 850 ohm resistor too easily, but I would be very surprised if 820 ohm wouldn’t do fine. 1/2W each will be fine. Finding caps should be easy. The values used are pretty standard, and it doesn’t matter if you use 16V, 50V or 100V rated ones (though 100V+ electrolytics could get physically large). Use what you can get. Jaycar should have something.

I am amazed you found a C828 transistor! I don’t think I could find one when I went looking (but it was a while ago now). The different code might reference different voltage or current ratings. At the voltages and currents we are operating at, I wouldn’t worry at all.

 

The behaviour you are seeing isn’t too different to what I was seeing. The circuit could get the ‘balance wheel’ moving a little, but not enough to get the clockwork going. Once I fixed up my components, the balance wheel would oscillate a lot more and would keep going.

I never tried testing at 9V. I used a bench top power supply to get my 12V. I’m not sure how effective the circuit would be at 9V. Even with the circuit working, at some lower voltage, the clock will stop working. I don’t know what that voltage is.

 

Since I first posted the repair write-up in 2008, I have never heard if anyone has been able to use it to fix their clock, though i see it has been downloaded many times from here and from classiczcars.com. So if you get it working, let me know.

 

I just downloaded the write-up and see that the oscilloscope waveforms have disappeared. I will see if I can find them and fix it.

 

And for the record, the clock I fixed in 2008 is still in my car and working well.

 

Good luck

 

Well, I got my clock working, I used 16V electrolytic Caps and a ceramic one (for the 220nf?) I will post the components that I used. I decided to try it after just replacing the caps and it worked great, even though the resistors seemed to be dodgy, I've only had it going for about 12 hours and it seems to be keeping time fantastically although there is no way to know just yet as only time will tell 

I will chuck up a list of the caps I got from Jaycar, I haven't tried the resistors as it worked fine without replacing them but we will see in a few weeks. Thanks again for the help!

[monkeyman]

 

Well that's good news. Well done. (Change a few caps and 'presto'... not so hard after all!).

Don't trust the transistor too much, keep it running on the bench a bit longer first.

I try to stay away from ceramic capacitors, especially for timing circuits. Their temperature coefficients are huge! A ceramic capacitor can vary by as much as +30% to -80% of its nominal value over its temperature range. I use polyester capacitors instead. They might cost a few cents more, but we are not buying them by the thousands.

 

If you find the time drifts a little, adjustment is with the lead screw. From memory, you get at it with a screw driver after popping out a plastic plug at the back of the housing (or since you have it out of its housing, the lead screw adjustment should be pretty easy to identify).

[Andrew_L26]

Well that's good news. Well done. (Change a few caps and 'presto'... not so hard after all!).

Don't trust the transistor too much, keep it running on the bench a bit longer first.

I try to stay away from ceramic capacitors, especially for timing circuits. Their temperature coefficients are huge! A ceramic capacitor can vary by as much as +30% to -80% of its nominal value over its temperature range. I use polyester capacitors instead. They might cost a few cents more, but we are not buying them by the thousands.

 

If you find the time drifts a little, adjustment is with the lead screw. From memory, you get at it with a screw driver after popping out a plastic plug at the back of the housing (or since you have it out of its housing, the lead screw adjustment should be pretty easy to identify).

 

Ok awesome, I'll see how it goes. I've got it in the car at the moment as It's not currently registered so I'll let it sit there lightly screwed in for a few weeks and make sure it keeps its time if not then I'll grab one of those transistors and replace whats left.

[Champ54]

Hi,

Thanks for your excellent post on how to repair the 260Z electronic clock. I have tried to repair mine but the best I can get is it will pulse when connected to the regulated bence power supply set at 12 volts. I have replaced all the capacitors and the transistor but nothing seems to get it going. I have even tried re-replacing the transistor as I thought that maybe the heat from soldering may have damaged it so I was very careful to heat sink it during the solder process but I still get the same result. If it tap the positive lead on the terminal at about 1 second intervals I can almost get it to clik over the mechanism but it wont keep going.

 

Do you have any ideas as to what might be the cause?

 

Also, can anyone tell me how to change details in my profile on this forum. I cannot find any access to it.

 

Thanks,

 

[Gtv240z]

I fixed one up yesterday and  it was a bit resistant to get going and then was a bit unreliable. I adjusted the preload on the pendulum mechanism thingo and it has been going for a few days now,

 

there are screws that adjust the shaft tension top and bottom. i loosened it off and it got going but the shaft was a bit wobbly so i tightened it up so it ran true. took a bit of fine tuning.

 

i am still a bit sceptical it may stop again though...

[Champ54]

Hi,

Thanks for your excellent post on how to repair the 260Z electronic clock. I have tried to repair mine but the best I can get is it will pulse when connected to the regulated bence power supply set at 12 volts. I have replaced all the capacitors and the transistor but nothing seems to get it going. I have even tried re-replacing the transistor as I thought that maybe the heat from soldering may have damaged it so I was very careful to heat sink it during the solder process but I still get the same result. If it tap the positive lead on the terminal at about 1 second intervals I can almost get it to clik over the mechanism but it wont keep going.

 

Do you have any ideas as to what might be the cause?

 

Also, can anyone tell me how to change details in my profile on this forum. I cannot find any access to it.

 

Thanks,

I took some close up photos and when I enlarge them on teh computer screen I can now see that 2 of the very fine wires from the induction coil are broken. I think the problem is that only 1/2 of it is working. I don't think this can be repaired.

[gav240z]

I haven't tried this yet, but it might work for early 260z clocks (Jeco style clocks).

http://www.classiczcars.com/articles/electrical/clock-repair-analog-70-78-z-round-r52/

[GongZ]

I haven't tried this yet, but it might work for early 260z clocks (Jeco style clocks).

http://www.classiczcars.com/articles/electrical/clock-repair-analog-70-78-z-round-r52/

 

As the article points out;

"If you want at this point you could calibrate the clock, except for one thing. Most power supplies supply 12.0v DC, while in the car you will be working with 12.8v to 13.5v depending on the condition of your battery and connections. To get it "perfect" you would need to match the voltage in your car. This takes a l o n g time, so leaving it in the car would be a problem, unless you don't mind having it dangling off on the side for days-weeks. So, if you don't mind it running a bit fast (as mine does), just hook it up to your power supply continuously for a few days."

 

I wonder if you could use a 12V voltage regulator to overcome this issue. 

 

 

http://www.ebay.com.au/itm/Linear-Voltage-Regulator-Modules-BEC-4S-Lipo-12V-For-Mini-QAV250-270-280-FPV-GL-/282561320836?hash=item41c9f79784:g:l8oAAOSw3YJZO9BE

 

If so, you could use this while you calibrate the clock attached to a power supply or battery and it would hopefully remain accurate when installed (with the regulator) into the car.