Interesting Cruise Control Brain Stuff
#1
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Been working on some cruise control brains that Roger had on hand and all of them are bad. Figured I'd take them apart and see what I can find as they don't work anyway and maybe I can learn something.
These three are all the same external part number and going from left to right. All are part number 928 617 127 00. They all click with the key on showing they have power entering the unit, and all click off when turned off but the failures are all different.
Far left will accelerate when when you push the cruise stalk forward but won't maintain speed. No obvious hot spots.
Middle won't work on any function but found two burnt resistors that I'm sure I can replace.
Right one will accelerate as soon as you push the stalk forward, and continues until you hit the brake pedal or turn it off. No visual burnt things.
We've sent off a few to be rebuilt and they always come back with the same issues and the only ones that have worked as they should are the ones from Mark at 928 International. Marks guy has it figured out so if you need one, talk to him. I'm just playing with these.![Big Grin](https://rennlist.com/forums/images/smilies/biggrin.gif)
Just thoughts for the community.
These three are all the same external part number and going from left to right. All are part number 928 617 127 00. They all click with the key on showing they have power entering the unit, and all click off when turned off but the failures are all different.
Far left will accelerate when when you push the cruise stalk forward but won't maintain speed. No obvious hot spots.
Middle won't work on any function but found two burnt resistors that I'm sure I can replace.
Right one will accelerate as soon as you push the stalk forward, and continues until you hit the brake pedal or turn it off. No visual burnt things.
We've sent off a few to be rebuilt and they always come back with the same issues and the only ones that have worked as they should are the ones from Mark at 928 International. Marks guy has it figured out so if you need one, talk to him. I'm just playing with these.
![Big Grin](https://rennlist.com/forums/images/smilies/biggrin.gif)
Just thoughts for the community.
![](https://scontent-a-lhr.xx.fbcdn.net/hphotos-xap1/v/t1.0-9/10849986_10204805559474739_3817537444734230576_n.jpg?oh=b5705fec0c470ad022b81a383077e86e&oe=550042F8)
#2
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Mine has the far left units symptoms - accelerates when stalk is pushed forward and then nothing else when released. its on my to do list![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
Watching with great interest!
![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
Watching with great interest!
#3
Race Car
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The one on the left is rigged/configured differently? (looking at two adjacent cylinders on the mid and right panels, and the positioning of the resistors. Are there build date stamps, given they are same part no.?
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#8
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Yes, that's been my impression, that electrolytic capacitors have the least longevity of any component.
About ten years ago, these things started to fail in all sorts of relatively new devices, such as a few of my wifi routers. Chinese manufacturers had gotten hold of a stolen formula for the electrolyte, but the formula left out a critical ingredient.
About ten years ago, these things started to fail in all sorts of relatively new devices, such as a few of my wifi routers. Chinese manufacturers had gotten hold of a stolen formula for the electrolyte, but the formula left out a critical ingredient.
#9
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Sean,
I have a few of these laying around too and would like to get one going for my 86. Interesting observation about the 928Intl rebuilds. I hadn't heard that before. There was a thread a month or so ago where several people named rebuilders that did a good job on their brains, and I meant to send one of mine off to one of those rebuilders but never got around to it.
I have a few of these laying around too and would like to get one going for my 86. Interesting observation about the 928Intl rebuilds. I hadn't heard that before. There was a thread a month or so ago where several people named rebuilders that did a good job on their brains, and I meant to send one of mine off to one of those rebuilders but never got around to it.
#10
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Back in the late '80's or early '90's, one of the top-rated Japanese electronic firms had a large run of "faulty" capacitors. They lasted for about fifteen years, then failed. I had to replace several on the Bose audio system in Lynn's STS.
#11
Burning Brakes
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Condensers made by frako, usually 100uF and 16volts.. Start to replace them, then change blown resistors. After that, I have 2 more steps for far left and far right:relais near pin plugs then ics... Usually have something like lm2901... They last forever but sometimes changing them is useful.
#13
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#14
Electron Wrangler
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Condensers made by frako, usually 100uF and 16volts.. Start to replace them, then change blown resistors. After that, I have 2 more steps for far left and far right:relais near pin plugs then ics... Usually have something like lm2901... They last forever but sometimes changing them is useful.
Alan