Friden 130 - strange behavior

[Alexandru Floca]

Hello everybody, i own 3 x Friden 130 (actually 1 x Frden 130 and 2x CE30 - the CE30 are identical machines, licensed copies manufactured in Romania)

Now one CE30 is working great, i have also tested the boards from the Friden 130 and the other CE30 in the working machine, so i have 2 complete sets of working boards and one defective C+D board. 

When i move one set of boards from the working CE30 into the Friden 130 or the other CE30 it starts with 4 rows of 0's but it only lets me enter one character, then resets back to 0. Also the image is rather blurry and cannot be tuned to look good. 

I have tested the psu and even recapped one of them, no luck. Still same behavior, no improvement. I could not identify any modifications on the backplane, the memory was bad in this two machines, one was fixed and should be ok as it tested good in the working one.  Any ideea what to test next?

[Cliff Stoll]

I met the designer of the Friden 130 / 132; I spent several hours with him (Bob Ragen).  He helped debug & repair my two Friden 132’s.

First thing he told me: the plug-in circuit boards are very fragile.  Don’t remove them if the thing is working!

Seems that in 1963, there was a patent on plated-through holes in printed circuit boards.  So Friden came up with its own method of making through-board connections.  

Friden’s method was not very reliable, and was the major cause of problems in those calculators.  Simple solder connections went bad. 

I have since built an “extender board” to let me test boards while they are powered up.

(Just hunted in my junk box and can’t find it.  Sigh.)

I can’t help much right now, as I am far from home.  Write to me after mid-april 2026 and maybe I can help you.

Best wishes,

Cliff Stoll.  Kleinbottle

:/ at &: kleinbottle dawtt com

Pi-day, 2026

Sent from my iPhone

On Mar 15, 2026, at 5:25 PM, Alexandru Floca <alexandr...@gmail.com> wrote:



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