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Coats 1001 wheel balancer display...please help!

Michael86

Member
Joined
Jan 30, 2018
Messages
20
Hello,

I have a Coats 1001 wheel balancer which was working perfectly for the 9 months that I've had it up until now. I was in the middle of using it a week ago and was on my second tire when the numbers on the display ended up all lighting up and staying lit. They are 7 segment displays and all 7 bar's were lit up all at once across all of the LEDs. When I hit any of the balance buttons the machine spins like normal but the display never changes. During a normal operation, the LEDs showed 0's on the display rather than all of the bars being lit up and then go dark during the spin and then after the spin show the balance needed.

I took the top cover off and ran a few spins and noticed that during the very last part of the balance cycle when it's slowing down an arc was being produced in the wiring. I turned it off and found a loose spade connector. I crimped it shut and made a good connection again and no more sparks were flying. I then shut the machine off and then after 2 hours tried again and it was working properly. So I figured that that was the issue.

I'll also note that today when I went to use it, it was working fine, and then all of a sudden the right hand display showed about 3 of the bars and the rest were blank, and then all of the display segment panels were dark. I ran a balance and nothing turned on. Then I cycled the power and it went back to the full 7 bars per display again. So clearly not working.

Does anyone know why my machine is doing this? Is there a common circuit board issue that I need to get fixed? Does anyone have a repair / schematic etc? Any thoughts or trouble shooting I can do to help you determine what the issue is?

Thanks!
 
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IndyGarage

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Apr 29, 2010
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Sounds like something is intermittently going bad.

I would check the board for burned or obviously bad components or cold/bad solder joints.
 
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Michael86

Member
Joined
Jan 30, 2018
Messages
20
I took a look at the board yesterday and everything appears to be good. I didn't put it under my microscope. The only thing that didn't appear great was the thermal paste on the heatsink from 2 - LM317's and one other chip. I scraped away the old paste and reassembled with new paste and then fired it up and used it for 4 tires and then left if running for a couple hours and it was working great.

I'm wondering if it was a heat related issue as it always happened after running it for a while (not long though. Maybe 30 minutes). But then again, after having it cooled down overnight, just before I took it apart, it was still having the same issue. Took it apart and did the paste and then it's working....I have this for personal use only so it doesn't get alot of use so I'll cross my fingers and try it again. If I figure anything else out I'll post it here.

Oh and the last thing I did was blow the years and years of dust off of inside of the unit as well as cleaned the PCB.
 

engineer2

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Dec 13, 2009
Messages
11,798
Location
Chicago burbs
Tiny cracks in solder joints can cause intermittent problems. It usually affects larger components. Might be help to re-solder the major thru-hole (non surface mount) components on the circuit board.
 
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Michael86

Member
Joined
Jan 30, 2018
Messages
20
Great point. I've got a lot on the go right now. If it happens again I'll pull the board and try that as my next course of action.
 
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Michael86

Member
Joined
Jan 30, 2018
Messages
20
Okay...so update here. I ended up tearing the machine apart and refinishing it as something to do while I was stuck at home in the hopes that cleaning up all the electical wiring / mounts would fix my issue. Fast forward until now and I ended up having someone take a look at the board and they found one bad capacitor and replaced it. It still didn't work. Then, they did some more work on it and resoldered some of the connector pins, removed the two "Coats" chips and replaced them and now it posts properly. That being said...I now have another HUGE issue.

The machine doesn't balance anything...I get consistent "000" on both displays after running through a cycle.

Does anyone have experience with older wheel balancers? I'm wondering if I messed up the Piezo assemblies while refinishing but have no idea how to test them (they look pretty much like the ones for newer coats machines part number "8114473" ebay sells a few but the cheapest is 290 USD for the set (which I'd pay, IF I knew it would fix the issue). I had the top pieces electro galvanized and seem to remember them being more magnetic than when they returned. Not sure if I might have screwed them up and need new ones based on that info?

If anyone lives in Canada near Ottawa and has experience with these older machines and could help out I'd also pay for someone who knows how to test / fix these machines.
 
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