re: [midatlanticretro] Reforming Capacitors: EAI Analog Computer TR-48
>stacks of information on Analog Computers, there is much to learn about
> I'm still working on the EAI Model TR-48 Analog Computer. I've found
them. I am guessing this project will take 6 months or more.
>about the old capacitor cans. I've done an hour of reading the internet
> In a few weeks, I'll be testing the power supplies, but I'm concerned
about "Capacitor Reforming".
>capacitors from the late 50's or early 60's?
> Does anyone have any experience or remarks to make about these CAN
> PS. We still haven't found an exact date for this computer.
You might want to touch base with Michael Pearson, he is located in West
Chester PA he can be reached here: http://ipgwcu.org/
>Yes, In my opinion you are correct.
> Here's a transistor with 430 on it. Would that make it 1964, week 30?
> Transistor part number is 2N1218. Or does the 430 refer to the factory the
> transistor was made? or other?
> Photo of transistor posted in the photos/Josh Bensadon folder of this group.
> I've seen some IC's with only a 3 digit code on them (not part of this analog
> computer). Case in point is the following:
> RCA H 650
> Is that to mean 1976 week 50?
> H being the factory where it was made?
In the early years of semiconductors most parts have three digit date codes.
You have to know the approximate decade the part was first produced to get the
Sometimes you have trouble telling the part number apart from the date code.
In the 1970s a lot of the 7400 series ic's had date codes like 7414 and a part
number like 7404.
I was always having trouble with those.
A good history of early transitor marking can be found here.