| Electronics > Projects, Designs, and Technical Stuff |
| Reverse engineered Friden 130 calculator power supply |
| (1/3) > >> |
| robertbaruch:
This is the power supply board for the 1964 Friden 130 calculator. This was an RPN calculator with a 4-line display on a CRT. The entire logic of the calculator uses discrete transistors. I'm gonna have fun reverse engineering the logic section. :palm: The power supply provides, from 120VAC input: +6VDC, -12VDC, -80VDC and -3kVDC. It also provides 6.8VAC for the CRT heater and cathode, and integrates the focus and intensity controls. There is a video input terminal which modulates the intensity voltage. Reverse engineering this thing is made difficult by the fact that, aside from the seven logic boards, everything is soldered down and non-removable. Please enjoy! Any comments are appreciated. Note that the component designators are my own, since there were none on the board. In looking at several 60's PCB's, it seems that designators for individual components wasn't a thing. If any designator was used, it was just to index the value of the component, so for example all 0.1u capacitors were, say, C1. |
| max_torque:
WOW, they do not make 'em like that any more! :-DD |
| robertbaruch:
Also, please enjoy this image of the power supply board, and this underside shot. As mentioned, everything is soldered. Not a single terminal anywhere. Once those boards are in, they stay in. :palm: |
| Alex Eisenhut:
I love everything about mid-century design. |
| gjruss:
Dear Robert A delight to see your posting of Friden EC 130 power supply. I restored a EC 132 some years ago. The major problem was the power supply. I resorted to replacing all the large electrolytics with modern ones by soldering under the board to preserve the appearance. It turned out to be the diodes that were faulty. This wonderful piece of modernity now sits in my company boardroom - much to the amusement of my younger clients. My father used to sell and install this model along with other Friden equipment back in the 60s - 70s. Regards, Gordon Russell Adelaide Australia ps I am now restoring a Flexowriter - one of the worlds 1st word processing machines - see image attached |
| Navigation |
| Message Index |
| Next page |