Vintage Car Clock

[promenade clocks]

Have a customer with a vintage Mustang model year 1979. There is purely electric clock with lcd screen and numerals. We repair electro-mechanical and purely mechanical clocks from cars but this is something in which we are not experienced. The clock is not functioning at all.

 

[Toughtool]

Since it is a quartz clock it may have it's own battery and not rely on the car battery.

 

[mxfrank]

This one will be powered by the car battery. The capacitors in these clocks dry out and need to be replaced. Less commonly, the display itself goes bad. You might want to run the question past MoMa Instruments. I'm not sure if they handle this particular model, but they may point you in a good direction:

https://momamanufacturing.com/

 

[skruft]

Also, there must be forums for Mustang enthusiasts who would have encountered this.

 

[Mike Phelan]

Vintage cars = pre-1930. This car and its clock will never be vintage, Victorian nor stone-age if it lives for 100 years!

 

[promenade clocks]

Thanks, guys. Hopefully we can replace the capacitors. Confident we can replace capacitors. If the lcd screen is dead then it may be hopeless. This is the type of car he grew up driving. So he has sentiment for this one. Thanks also for the education about the proper nomenclature.

 

[Chris Radek]

I would guess this is a VFD, not a LCD screen. If so it will have both a high voltage (50-200V?) and a low voltage (1-2V) filament power supply. I agree replacing the caps is the first thing to try. It may also be made of a lot of TTL so it needs a whole lot of 5V. If you open it up and take some photos we can give better advice.

 

[Schatznut]

Vintage cars = pre-1930. This car and its clock will never be vintage, Victorian nor stone-age if it lives for 100 years!

Ahh... a car snob. So am I. Pleased to make your acquaintance!

 

[Mike Phelan]

Definitely noot a snob of any sort! Our two cars cost less then £1000

 

[Schatznut]

Definitely noot a snob of any sort! Our two cars cost less then £1000

...and my newest car was built in 2004. It appears we are of a like mind!

 

[Mike Phelan]

Definitely!

 

[promenade clocks]

Thanks for the help. This is almost for sure a VFD. I do not understand what you mean by 5V, this should be a 12V system. I have a 12V adaptor, will this work to power the unit? How many amps should I use? How do I tell if the capacitors are bad vs. the display?

Thanks again and happy holidays

 

[Schatznut]

If you provide 12VDC on the power leads, that should do the job.

There is likely a voltage regulator right across the input power that will take the car battery voltage down to logic-level voltage unless the logic circuitry is CMOS. There may also be a boost converter that will generate the voltage for the VFD. They generally run from 12 to 40 volts; one may not be necessary on this one. But any secondary voltages will be generated off the 12VDC coming in.

 

[Bill Stuntz]

I have to be suspicious of the rusty can up by the wires. What is it? A crystal? Any readable markings on it? I think I'd look into changing that first.
Do you have a wiring diagram for the car? Knowing the purpose of the wires in the harness might help. One will be ground, one will be hot 24/7 to keep time, one is probably "light the display" when the ignition is on. What's #4? Instrument panel lights when the headlights are on?

 

[Chris Radek]

I agree that the can is probably a crystal. The big IC under the display is probably CMOS and is run from the zener (Z2) and power resistor surrounded by overheated browned circuit board. One of these parts sure might be bad, they work hard. (Or maybe this is the filament power supply?)

It's going to be hard to test this out of the car, without knowing what the wires are for, as Bill says. But if you can figure that out, test for the right voltage on top of Z2 (look up Z2's part number and you can see what voltage it should be). Then test for filament voltage (you can see where the pins are by just looking at the display) which should probably be 1-2 volts. You should be able to see the filaments *barely* glowing in a dark room. If they aren't, you won't get any display for sure.

There should also be a higher anode voltage on pin 18 if you count the same way I do - again you can see the pinout by inspection, anode is 8 and 18 but 8 is not wired to anything. If Schatz is right that 12V is enough anode voltage for these (which is great, and news to me, thank you) then it'll just be 12. Or it might be higher.

Use good static electricity hygiene when handling this! The IC might be very susceptible to zaps.

 

[Mike Phelan]

If there are any electrolytic capacitors in it they will need replacing by now - cost pence!
If it's original in the car it will be powered by the car battery rather than having it's own battery.

Like I said, it isn't vintage and never will be.

 

[NoBrand]

These might help a bit:

thats from my 83. Basically, all it takes from the car is 12+, 12v acc, illumination signal and ground. Earlier models could also come with a clock that only had power and ground, but those are very early foxes.

the clock in the console of a fox mustang is largely self contained. All it takes from the car is 12v power. As far as “electronics” go, these little units are pretty basic, not much to go wrong. If you don’t find a burnt resistor or leaking cap, its probably cheaper to find another in the scrap yard and just swap it out. They’re not too expensive, I’ve got 3 or 4 in a parts drawer somewhere and probably another 2-4 still in their consoles up in the rafters.

The drivers message center is a different story. It uses sensors out in the cars wiring harness for info. For example: fuel level is handled by a summing unit behind the passenger dash panel. The “light out” actually looks for a specific resistance and the car needs the harness for the lighting with special resistors out in the harness in various places. Its PITA to swap a console into a non-console car, mainly from just chasing down the wiring. When I swap in a console, I make sure I pull the dash and lighting harness from the donor car. Last one I swapped in I just unbolted the entire dash and walked away with it. Much easier to just swap the dash plastic with the needed sensors and wiring already installed.

if your buddies mustang is in decent shape, tell him to hold on to it. Early foxes (302/5L) are starting to go for good money. Its not uncommon here to see clean axamples asking anywhere fron 25-50g, depending on option level and condition. The Fox chassis is experiencing what every “performance” car eventually does: the guys who couldn’t afford them when they were new now have money and want to scratch that item off their bucket list…and they are willing to pay for it.

last year, I actually had a guy offer 25G for my 83. It has t-top, 302, 4bbl, 5 speed, etc and its still a ”non-running” project car. You tag the right guy and they are willing to pay pretty decent money for them. they’re not exactly “rare” (ford pumped out a gazillion of them), but the earlier “4-eye” foxes are getting harder and harder to find in GT and good, unmolested condition.

 

[Bill Stuntz]

Looks like the wire colors change at the connector going into the clock. You may need to look at the wires at the car's connector to determine which of the clock's wires are which. It looks like ground will be black as expected, but I'm not sure about the others.

 

[NoBrand]

one more thing I’ll add is that automotive electronics from this era suffer quite often from what is commonly termed “cold solder joints”.

what happens is the solder cracks and breaks quite often, either from age, vibration, corrosion or faulty soldering when assembled.

when I zoom in, I see what looks like corrosion and a broken solder joint at the red wire. The red wire is likely 12+ constant, whcih could explain the clock being totally dead.

all you need to do to test/fix these joints is reflow the solder with a soldering iron. Just be sure to clean any grim or corrosion off the joints before reflowing the solder.

 

[Bill Stuntz]

I see several other suspicious solder joints:
Looking at the wiring diagram, it might be worth trying to apply ground to the black wire & 12V to the other 3.

 

[Mike Phelan]

one more thing I’ll add is that automotive electronics from this era suffer quite often from what is commonly termed “cold solder joints”.

what happens is the solder cracks and breaks quite often, either from age, vibration, corrosion or faulty soldering when assembled.

Quite often they're not visible, either. Same on radios and TV's. Modern lead-free solder is worse.

Just be sure to clean any grim or corrosion off the joints before reflowing the solder.

Not too grim when you can fix it!

 

[NoBrand]

Quite often they're not visible, either. Same on radios and TV's. Modern lead-free solder is worse.

Not too grim when you can fix it!

Lol! Should have been “grime”.

stupid iphone….

 

[Mike Phelan]

Lol! Should have been “grime”.

stupid iphone….

It's those damn spill chuckers ...

 

[RODALCO]

Reply Nr 14. The rusty can is the crystal oscillator for keeping accurate time.
(bit of rust on the outside of the can shouldn't matter)

This is a VFD display, it looks in good condition, the filaments look intact. the darker corner is where the getter is triggered during manufacture to seal the display.
The black electrolytic capacitor may require changing, it doesn't look bulged but the electrolyte may have dried up.
Some solder joints at the supply leads can do with a reflow of fresh solder.
Check the Zener diodes if they haven't gone short circuit and pull the voltage down to the display, hence no illumination.
The little black D shaped transistor or voltage regulator may need checking too. Good to know what code is stamped on it.
Older stereo equipment used these displays to for VU meters. Supply voltage was never higher then 15 Volts. Filaments usually run at a couple of volts.

Vacuum fluorescent display - Wikipedia

en.wikipedia.org

good link to read about VFD's.