zclocks

Hussein, After you replace the transistor did the clock start on it's own when power was applied? How long did you let it run before you assembled back in the housing? My thought is that if it was running and then stopped when you reassembled the wiring (ground and power wires) might have touched the mechanism and caused a problem. You could have a lot of resistance in the spring and or the pivots of the balance wheel. Check the spring shape, teeth condition of the pink wheel, and the pivots. If the bearing are worn to excess the wheel will not run smoothly. If you push the wheel it should take several seconds for it to stop. Please post another picture of the circuit board mounted in the assembly. Ron

Hey Yarb thanks, I really like helping when I can. I have been helped many times from this site and when I can pay back I do.

Captain is right you should be jumping for JOY!!!

Yes, You might have cooked the trans. The coil resistance values can be different and that is why you have 2 -680 ohm resistors . You coil resistance is high and low , but I think it will still work. The normal value of the resistor next to the transistor is 850 ohms. I think they were varying the resistor value depending on the coil resistance/ inductance. This is why I always stay with the same values of the components of the board I'm repairing. Jeco did some weird things.

What I ment by "crystal clear" was that the drawing of the 3 transistors isn't clear. I need to rotate the transistors 180 degrees.

Oh shoot! I'm sorry the drawing should have been crystal clear. I think you have it now , but this is what your new installation should look like. Did you power up the circuit board with the tran in your configuration? Ron

One more item. Check the coil resistance . You should have 200ohms on each coil.

Check the trans configuration as I've posted here. You can modify anything, but the NTE 199 is a direct fit. BTW I also have a 75 280z Ron

Ok, I couldn’t take it any longer without making a couple of comments. You can break out the test gear and spend most of the day looking for the bad part or just replace the caps and transistor. To start if you apply 12 vdc to the assembled clock and the balance wheel moves the coil is good. The wheel may move ever so slightly so look closely. If it doesn’t then the coil is bad and you need to find another board. De-soldering /soldering is the biggest problem because you can cook the insulation on the coil wire. Once that happens you destroy the coil. No joke you need to be uber careful soldering the 10uF cap next to the coil. Guess which cap usually goes bad? These are electrolytic caps and you need to replace all with the exact values. No subs. You can also have a bad transistor (C828) so why not replace it. Almost any general NPN low noise amplifier transistor will work. The zener diode rarely goes bad unless you’ve applied something like 24vdc to the board. I’ve seen it happen. These 4 parts cost around $5 and will last years longer that the originals. Last, but not least I don’t charge $351 to repair this board, that’s a completely refurbished clock converted to a Quartz unit. I do have this repaired 280z circuit board for $60. Good luck and let me know if you need help. Ron

You may want to add vacuum meter to see what else is going on.

View Advert Rc clock for 240z For sale is a Single knob rally clock converted to fit a 240z. The clock has been repaired and completely refurbished. Cost is $600 plus shipping and taxes If interested please contact ron@zclocks.com Thanks for looking Advertiser zclocks Date 08/13/2023 Price $600 Category Parts for Sale

View Advert Rc clock for 240z For sale is a Single knob rally clock converted to fit a 240z. The clock has been repaired and completely refurbished. Cost is $600 plus shipping and taxes If interested please contact ron@zclocks.com Thanks for looking Advertiser zclocks Date 08/13/2023 Price $600 Category Parts for Sale

You have to love the car and be willing to spend the $$ to bring it back for a second life. I think the key is what 87jm said about his experience with a very poor resto shop. I've been there and spent big dollars and years trying to correct what a certain So Calif shop did to my 280z. The real take away is find someone who has used a particular resto shop, is very satisfied, and use them. A good shop that loves Datsuns is worth everything. I hope you restore your car or sell it to someone who has the resources to restore it correctly. Good luck

Ok Thanks. I have one of the brackets and didn't know where it mounted.

What does the inboard bracket look like?

Ok, I get it. I couldn't tell what the pink thing was, It's a red hot nut. duh!!

Question. How did you remove the broken stud? Ron

View Advert 280z RC 1-knob/ calendar clock For sale: Totally refurbished 1-knob /calendar RC for the 75-76 280z. The clock will fit the 77-78 280z , but the number font is different for the later years. Please let me know if you have any questions. PS: This is not a quartz clock Thanks for looking Advertiser zclocks Date 05/29/2023 Price $550 Category Parts for Sale

View Advert For Sale--Rally/Calendar clock 240z 4 sale is a Single knob rally clock converted to fit a 240z. The clock has been repaired and completely refurbished. Cost is $600 plus shipping and taxes If interested please contact ron@zclocks.com Advertiser zclocks Date 05/19/2023 Price $600 Category Parts for Sale

Also, change the oil filter when you change the oil.

Racer X, Forgot to mention that there are NO jeweled movements in these clocks. There are brass bushings on the ends of the shafts.

Yes, I do repair these clocks and also convert them to quartz units. Take a look at my web site. zclocks.com

The clock is very susceptible to any resistance in any part of of the gear path. I think you will find that the main drive gear is the problem. If the bearing is worn, as pictured in the attached diag., the larger gear driven by the motor is allowed to not mesh correctly with the motor drive gear. This in turn binds the all the gears in the train and the clock stops. The only way to verify this is to totally dis-assemble the clock and inspect / clean all the parts.

View Advert WTB 280z/280zx analog quartz clock If you have either of the 2 clocks as pictured For Sale please contact me @ zclocks.com. Advertiser zclocks Date 12/09/2022 Price $1 Category Parts Wanted Year 78 Model 280z

I have used Damper DR in Redding Ca. They did a great job , but cost was $225 with shipping. You have to supply the damper as they mostly do American cars.