Speed warning device in 1967 instrument cluster.

[Domenic T.]

I just hooked up my cluster and my speed warning device started buzzing. I put 2 new gears in but couldn't find a few that needed to be replaced. I located the parts with FORUM help at a spedo shop. The shop recommended that they check the magnets and re-calibrate the speedo so they assembled the speedo. I think I tested the warning circuit at the speedometer when I got it back.
My question is: Is one of the speedo mounting screws supposed to be grounded? There is a small brass grounding terminal/strip, (about 7/16 x 1" with jagged edges) that I put under one speedo mounting screw. The AIM U15 A1 does not have much to look at!
Was that small ground terminal/strip supposed to be at another location?

Dom

[Joe R.]

Re: Speed warning device in 1967 instrument cluster.

Dom,

The small brass clip has to be used on one of the mounting screws on the back of the cluster.

JR

[Robert R.]

Re: Speed warning device in 1967 instrument cluster.

Domenic
Was the cluster taken apart? It's been too long to remember all the details, but on my '67 back in the late 70s, I needed to have my speedo re calibrated. When I picked up the car, the buzzer was on constantly as soon as the ignition switch was in the On position. The speedo guy concluded that he forgot to put a small washer that separated the two display needles, and had to pull the cluster apart again to replace it.
Bob

[Brian T.]

Re: Speed warning device in 1967 instrument cluster.

These units are very touchy. The face needs to be insulated entirely. Plastic screws, fiber washers between the face and odometer frame, and also elect. tape and small foam pieces over the 2 screws that mount the odometer frame to the main frame. If there is continuity between the face when the pointer hair spring is away from the pin on the yellow pointer, the buzzer will operate.

[Domenic T.]

Re: Speed warning device in 1967 instrument cluster.

Joe, Robert, & brian,
Thanks.
Sorry it takes so long to reply but I can only get your responces on my E-mail, NCRS for some reason will not display on any computers at my home. my portable computers will get NCRS elsewere.
Yes, just put the cluster in and the warning buzzed as soon as the key was turned on. I purposely grounded the speedo thinking that that was what was needed.
I did put ALL new insolators on the speedo mount and will remove the ground. Brian< I know what you mean about the wisker inside, back in 1971 when I had the spedo apart, it gave me a headache.
I will remove the ground and try to figure out which screw that small ground os under. My best guess NOW is that it helps ground one of the 2 sets of instruments at each side of the cluster. The oil line should supply a good ground to that side, so maybe it goes on the fuel & amp gauge side.
Couldn't find that info in the schematics or AIM.

DOM

[Brian T.]

Re: Speed warning device in 1967 instrument cluster.

You are on the wrong track. The brass piece with the "teeth" grounds the frame. When the speedo pointer hair spring touches the pin on the yellow pointer it completes the circuit, supplying a ground for the buzzer. As I suggested earlier, sounds like the circuit is already grounded, and that is why the buzzer operates. You can give me a call at 760 568-6450.

[Richard M.]

Re: Speed warning device in 1967 instrument cluster.

Here are some photos of one I repaired. The buzzer operation was intermittent. This was discovered after I solved it's major problem of a stuck speedo needle caused by over lubrication.(pics at end of post).

The buzzer operation problem was caused by a bad contact at the internal speedo-cup spring where it touches it's mounting clip at the back of the housing.

Here are some details.

Before disassembly.
PA300085.jpg

Oh boy....now what!
PB170026.jpg

Notice the small washer.
PB170027.jpg

Setpoint shaft detail. Don't lose that c-clip.
PB170028.jpg

Here you can see the spring. This must be grounded to the bracket. It transfers the ground path up and into the speedo needle through the speedo-cup shaft. There on the speedo needle is a contact coil spring. When that touches the set-point needle(which ultimately connects to the buzzer), then the circuit is completed and activates the buzzer. It's a very light coil spring on the speedo needle so that it has a negligible effect on speedometer accuracy.
PB170034.jpgPB170035.jpgPB170036.jpg

A critical area is where the micro-spring makes contact to the grounded bracket. that hook on the end of the spring. A poor connection here can cause intermittent "on" operation. A touch of solder can help here.
PB170037.jpg


This is the backside of the speedo face showing the set-gears for the set-point needle pointer. The special brass (or copper?) contact must be isolated from the case. If not, it could continually buzz. That may be your problem.
PB170040.jpg


After removing the speedo needle showing some details. The setpoint shaft goes through that gear with the hole in it. That's how the set-point needle is adjusted.
PB170005.jpgPB170006.jpgPB170007.jpg

Here you can see the tiny speedo needle spring contact. When it makes contact to the yellow set-point needle, it will activate the buzzer.
PB060017.jpgPB060018.jpgPB060019.jpg

Other contact points and visuals of the internals. Notice the insulating washers and that additional insulation was added to help prevent false ground shorts.
PB060020.jpgPB060021.jpgPB060022.jpg




Here is the jagged edged grounding piece. It mounts on the upper speedo housing mount screw as shown. This ensures that the case, which gets grounded from the cluster harness ground, is transferred into the speedometer mechanism mainframe.
(Note "LE" is wrong on this cluster)
P1160079.jpgP1160080.jpg

This photo is missing the ground piece. It was taken before I noticed my assembly error.
P1160076.jpg


P1160078.jpgP1160081.jpg

Regardless of what's causing your problem, you may have to remove the cluster so you can get at the internals.


BTW, the reason this also came to me was due to a stuck speedo needle.....at 40mph. We thought it was the speed warning circuit. When I opened it up, it was pretty obvious it wasn't that!
PB170001.jpgPB170003.jpgPB170010.jpgPB170018.jpgPB170022.jpg


Rich

[Domenic T.]

Re: Speed warning device in 1967 instrument cluster.

WOW,
wWhat a good presentation. wish the book was 1/10 that good. the one thing that wrapped it all up was the ADVIL bottle in the pics. How many Advill does it take to do what you did? Thanks for taking the time to do such a wonderful post.

DOM

[Richard M.]

Re: Speed warning device in 1967 instrument cluster.

WOW,
wWhat a good presentation. wish the book was 1/10 that good. the one thing that wrapped it all up was the ADVIL bottle in the pics. How many Advill does it take to do what you did? Thanks for taking the time to do such a wonderful post.

DOM

Thanks Dom, Glad it helped. I kinda just threw it together from memory. That's why I take photos of most all of my restoration and repair work. So I can recall what the heck I did later in time.

The Advil is used for a very important step.......I usually take 2 just before getting under the dash to get the cluster out. I then do my work comfortably at the workbench with no back pain. Then I take another 2 before I get under the dash later in the day to reinstall the cluster.

Rich

[Bill W.]

Re: Speed warning device in 1967 instrument cluster.

This is why the NCRS and the Discussion Board are great . Where else could you get all this information with photos for free .

[Richard M.]

Re: Speed warning device in 1967 instrument cluster.

This is why the NCRS and the Discussion Board are great . Where else could you get all this information with photos for free .

Bill, Much credit goes to the IT team, and John Waggoner in particular, who decided upon a request some time ago to allow the "unlimited" number of photos in posts now. The old limit of 4 in each post made it very cumbersome to try to supply multiple photos in a description of problems or to be a aid to answer questions.

Kudos to John and the Team. Thanks Guys!

Rich