The reliability of the Backplane was never high in the beginning. And I believe there was at least 2-3 revisions to the backplane. One of its great weaknesses was that that you simply can not test it. Part of that mentality was the "Pluck and Chuck" repair system. Every troubleshooting guide gets to the Backplane, and the answer to the 1 million dollar question is, CHANGE IT and see if it works. At $1,788.00 bucks a pop. The Backplane was a recoverable item. It HAD to get sent back to be inspected/repaired, so you had to have one to get one. Anyone in the Army longer then a few years knew how to get by that requirement. At one point, the Item Manager personally decided what parts request in the world got satisfied first. Often we got one in, installed it, and it was no good. QA/QC sucked.
But no real test procedures. That's what angered most folks. And changing it was not fun. You have never lived until you have done it in a CBR suit, in 115 degrees.
The I&O was the same way, if not worse. Same problems. The reliability was bad. QA/QC was bad. If you need to get 2-3 to get the set to run, something is wrong. And there was still no way to test it other then replace it at $2,266.00 Often it was damaged by people plugging in a Volt Reg, or Elect. Gov component. You get it in right, or forcing it in breaks something. It seemed to vibrate very much, and that may explain the failures somewhat. It seemed to me that simply too many functions passed through this card. Just about every troubleshooting diagram led you to the I&O, and said change it. Sometimes you could see burn traces and cracks under the coating, but mostly, it was so dirty, that was not possible. I can remember one time period, that it was simply impossible to get one. They failed so often, that people started ordering them, (read hording here) even if they didn't need one. Why? You knew you would need one soon.
The MPU. Now that was something very different. Yes, they sometimes went bad. Not all that often, no, not really very often. The problem with the MPU, was Pvt. Schmudlap. Without fail, (and I admit I did it twice also) he was screwing the darned thing in too far and grinding the end off, when the engine turned over. And not once, or twice! Sometimes more often.
And if you don't screw it in far enough, then the Elect. Gov will not work. More Injector pumps, Fuel Cutoff Solenoids, Elect. Governors ordered/changed, and who knows how many fuel systems being taken apart and replaced because of this little puppy being ground off or not being screwed in far enough, you could finance Microsoft for a year. This is NOT a lie. Vibrations, and no Lock Tight, also caused this thing to "fail". And for years, they came without the small electrical connectors. Most folks simply cut them off, and twisted them onto the new MPU. Bad connection, bad response. Since it a magnet, it collected metal filings and dirt/grease and all that. So it stopped working. Schmudlap pulls it out and cleans it. And so the circle starts again. In reality, it was simple to install, simple to test and it caused more havoc then any other part on the set. ANY TQG that turns over, but wont start, should have its MPU pulled out first thing and checked. Or checked at the Gov. terminal board.
