Grand Daughter Ava and her Cat
One of the more brilliant technical works I have ever read was authored by Forrest Mims, but I’m not sure if there’s even a hand full of people that really know why they are such great works. My summary of his work? It’s like pouring knowledge out of a can. It’s rather dumb founding how clearly written his explanations are.
Forrest wrote a whole series of Electronic books for Radio Shack and many of us learned from him. Fact is, I keep a number of his books on my shelf as a quick reference. One book that really shows off Forrest’s talent to communicate clearly is a book called Understanding Digital Computers, Forrest designs a nibbler processor to teach the inter workings of a computer, and you walk away with a deeper understanding than most people will ever have.
But now I’ll tell you the secret, and if you are a developer of anything that needs instructions, it can put you light years ahead of others including your competition. Forrest was learning as he wrote! This allowed him to explain what he was doing in terms that a person just learning could understand, because he was just one step ahead of his audience.
I write this because the last few days, I have been pouring over the worst of the worst technical manual I have ever read. The instruction was written by a man that has done the work so many times, there’s no way he can really relate to the person who is doing it the first time. I found an account given by two geeks, (both engineers) who took a week to complete the same work, the Author calls it a 10 hour job, but I didn’t do any better than the two geeks.
The biggest mistake you’ll make is giving the job to document the assembly or the use of a product to the man who knows it best. If you want clear and concise instruction, you find someone who knows absolutely nothing about it.
I’ve been studying this process for 40 years or more, and I just think it must be counter intuitive for managers to grasp that they need the untrained to write the manual so the untrained can learn it best. Sure thing, they’ll struggle, but they will discover the majority of the potential misunderstandings in the first draft.
Next thing I’ll write about is a product that Marketing said needs no lubrication ever, but the lack of lubrication takes out the poorly designed controller that then takes out the motor. How could they get it so wrong? Well.. it happens after warranty so no big deal…. (for them).
All the best,
George B.
Hi George,
I too am a fan of Forrest Mims III from age 9 to 57 and still learning from him. Perhaps the time has come for others to learn from me passing it forward and have fun doing so. Unlike ST12 Chinese translated instruction manual and no mention trouble shooting section for hearing ticking noise as 40mm shaft is turned by hand. Is that normal one ponders and reasons it must be since a QC inspection stamped right on the manual confirms the experts confirmed it was AOK.
Long story short, ticking noise is not normal at all. A faint opaque grease trail on the inside bezel behind the metal fan blade is a good indication the shaft bearing seal is not where it should be but is hardly visible to the human eye even with high power LED flash light in had. Needless to say one can not get their Godly engineered fingers between fan blade and bezel to firmly push the rubber impregnated metal seal ring back in the grove of the bearing it slipped away from. Just be sure to have your heat gun handy to expand the bearing cavity prior to parting the bearing from the bezel cavity it rests or you will likely break the very thin cast iron bezel in the process.
On an other note Forrest Mims might be proud of what was accomplished a few of his engineering circuits coupled to infrared reflective sensor, encoder ring, frequency multiplication digital decade counters being passed to a phase lock loop can produce robust motor commutation. Our KickStarter presentation opted the same V36 digital motor use sensorless FOC commutation to show the playback of a mock solar energy source. The ST12 produces an true sinusoidal wave form of little harmonic distortion when coupled with an self powered soft start induction gen regulator placed inside the dog house. One might say ST12 running inside a house might be bit noisy yet is hardly heard in the next room while watching TV or having a quiet conversation with friends.
Please see our KickStarter fund raising preview.
https://www.kickstarter.com/projects/841082029/1953739391?token=73915180
When Forrest shared the Phase Lock Loop I had to have one!
You are the only one I remember talking of a ticking sound from a ST head. Few will ever understand the varying quality of the ST Heads, lots of different companies made them, some geed, some not so good, and never forget the yak fat man.
Brett… we don’t want to mislead a reader, I think it’s 42mmm 🙂
Still have Mims III Radio Shack Engineers Notebook I & II from the 1970’s, the graph paper pages are now quite brown but dang some of the best circuits ever he an another fellow documented most clearly.
Perhaps I’m the only one who ever thought to turn 42mm shaft by hand to check for bind up or shaft issues. Luckily the front seal had plenty clear grease on back side, enough to smear liberally on those steel balls. So far remains quiet no more ticking sounds and note the rubber on both outer seal was a bit spongy compared to other bearing seals I’ve taken off. We currently use large SK bearings 2.574″ Id with the DC motor shaft and those balls are even larger. SK uses blue Mobile electric motor grease that changes viscosity with temperature rise and solidifies upon cooling. So the first few ticks of commutation are a bit strained until all the bearings greases warm up.
During that tear down maintenance noticed the slip rings are starting to form a brush grove as the brushes seem a bit wide and one was over cutting, had very thin lip forming. Spent some time to insure the alignment of brush holders were not skewed relative to rings and each had similar spring pressure since it seems that might have caused the grove to form. Hard to imagine a brush grove forming in brass slip ring with such little usage time.