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EA81 Digi Dash Help Needed


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After I noticed that my dash was whistleing when I turned the car off, I was told to have my alternator checked for proper voltage. I took it to Schucks today and here are the results:

 

Actual Battery volts: 14.40

Actual Rippple volts: 0.29

Actual Lamp On volts: 2.46

Actual Lamp Off volts: 14.32

 

So apparently, my alternator is just fine. The manager of the store said it might be a bad diode, but where the heck is that? How do I check it and replace it if needed? Also, it was suggested that I make a better ground from the digi dash, but I'm confused as to what actually needs to be grounded? The digi dash itself? The ground wire coming FROM the digi dash? Add a ground? Any help you guys can suggest would be great.

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You stated the you heard the whistleing after you turned the car off. If that is so, then what you may be hearing is the power supply for the dash display. The vacuum florescent display requires a higher voltage then the 12 volts of the car system power. The sound you hear may be from a switching power supply for the higher supply voltage.

 

I'm not sure what to say about the ripple out of the alternator. It sounds a little high but it may be ok. I would check the output with a oscilloscope before replacing the alternator to see if one of the phase ripples is missing. Make sure your charging system connections are clean also.

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i fixed a lot of the fluttery ignition issues by replacing the ground wire from the engine to the battery(had very light corrosion through almost it's entire lengh) as well as sanding and/or replacing all of the grounding components (connecters,wires) from the battery to the wagons body. oh and hit all that up with some silicone grease or something to protect it form future corrosion.

 

as for the alternator, i am in the same boat. i had it tested last week with satisfactory results (so says the test machine, yeah sure). so i'm am gonna have to buy another new one or buy like three used ones from the junk yard OR just maybe find someone with an o-scope :brow: :brow:

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Be *extremely* careful when working on that digi-dash. They fry very easily. Just the alternator going out can fritz them.

Seems like nobody can fix them, and they are more rare that hen's teeth in the boneyards.

I noticed that squeal from one of mine on rainy days. Almost certainly bad connections.

Apparently they were made with a corrosive solder that doesn't last.

Find a good electronics man to re-solder all the connections and add some sort of protection circuit (xener? tube?).

I have a schematic for them (the '84s) from a FSM.

If you like I can scan it for you.

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my trip computer still goes black after ten or fifteen minutes of driving. luckily it has come back to life after the two times it has done it--my original one didn't. this is on a broken one i got from pull-a-part, i wouldn't dare put the working turbo one i just got in it till it's all A-OK. though even with my almost fully working old one it would occasionally go black and the buzzer would come on halfway driving somewhere. Also, before any of this started, when i would first start the car, once out of every three times the gas gauge would read full no matter how much gas was in it for a minute or two after turning on the ignition switch, then go back to actual. it sometimes would not go back to actual at all unless i turned the engine on or let it sit with just the ignition on for around ten minutes.

 

what about installing some sort of external voltage regulator in line somewhere? is too much voltage being produced usually the primary problem and/or bad grounds that cause electrical pressure to build or is there something else that could be going on?

suggestions, ideas? please, i have no idea where to start...

 

-no hijack intended (just consolidation) -

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The EA82 digidashs have an annunciator that warns of bad power input, and I would imagine that the EA81 has the same. I am awaiting schematic/test info that is supposed to be in the FSM, but haven't connected properly with the local Member that has offered the info (90% my fault :) ).

 

I have several EA81 DigiDashs, compliments of Turbone, and have plans to fix them if I can get a little info and/or a car that I can test them in. I have seen nothing that indicates that the wrong solder or "bad" solder was used on these. What they do have is much the same problems as the dash clocks: 20+ years and some overly warm resistors melting solder joints. The dash "power supply" is pretty much just a 7805 voltage regulator IC, which I expect just gives up the ghost after 20+ years of getting hit by frequent voltage spikes.

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The problem with my dash isn't that its blacking out or squeeling while I'm driving. It only makes the noise when I shut the car off and just recently some of the columns of green tubes have gotten a little dim. Is this the same sort of thing that happens when they blow on everyone else's car?

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The problem with my dash isn't that its blacking out or squeeling while I'm driving. It only makes the noise when I shut the car off and just recently some of the columns of green tubes have gotten a little dim. Is this the same sort of thing that happens when they blow on everyone else's car?

From what I have heard, most other dashes squeal while engine is running, and then just go out. Sounds like yours is more of a battery power (+-side) issue, or possibly a ground, to the dash itself. As in, the dash is not getting sufficient voltage and current while the alterator is not helping to prop it up.

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northie, i thought that carfreak got them scanned for you instead since i didn't hear from you. my bad completely, if you still want the FSM ('83) let me know.

 

freak, the bars of just my temp gauge on my original one would all be fading in and out, like each bar would be a different brightness, until i grounded the temp sensor wire in the engine compartment. at which time they all would light up the same reading full temp. nerver figured it out though...

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northie, i thought that carfreak got them scanned for you instead since i didn't hear from you. my bad completely, if you still want the FSM ('83) let me know...

As I typed, 90% my fault. Working 2 jobs makes it hard for me to keep track of things. If you still have it, sure. I need to pick up a part from carfreak85 soon, so maybe I can combine trips.

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As I typed, 90% my fault. Working 2 jobs makes it hard for me to keep track of things. If you still have it, sure. I need to pick up a part from carfreak85 soon, so maybe I can combine trips.

 

I believe I have the wiring diagram also, but I need to double check.

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alright fine... i'll take that ten percent, and actually sind it to you this time.;)

 

As I typed, 90% my fault. Working 2 jobs makes it hard for me to keep track of things. If you still have it, sure. I need to pick up a part from carfreak85 soon, so maybe I can combine trips.

 

galen, there are two places the wires ground under the drivers side of the dash: on one of the two bolts that holds the steering column to the body, and one (underneath the speaker) on or imediately next to the far left side of the metal bracket that the fuse holder is bolted to.

other than that, it most likely is in the grounds in the engine compartment.

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  • 2 weeks later...

Well guys, after poking around and looking for things to ground, I found that the grounding strap for the transmission to the body of my wagon was disconnected. The hole in the body was stripped so I used a bolt to secure it. When I went to check the dash, the crazy shutdown noise was gone as were the dim display on my dash! :banana:

 

So, the moral of this story is to check your grounds for any strange electrical problems you might have.

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  • 6 months later...

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