HP35 - for your personal viewing pleasure on Friday

[Frank Boehm (Germany)]

Thought I'd share these two pictures:







Please note the datecode as early as 7145, predating the official release by about 4 months; the ROMS are 0005, 0006, 0007.

[Stefan Vorkoetter]

Very nice! What really strikes me about this is the layout of the traces on the PCB. It was obviously done by hand, long before the days of auto-routing. This clear from all the odd angles and uneven spacing, and probably allowed more stuff to be crammed into less space than if everything were on an even grid, with lines only at 0, 45, and 90 degrees as is common these days.

Stefan

[Walter Lam]

I wonder whether anyone can post the internal of HP 35s.

[Don Shepherd]

I know that someone did that in the forum last year. Look at the archives. There were hundreds of threads about that calc last year.

[Seth Morabito]

Quote:

---

It was obviously done by hand, long before the days of auto-routing.

---

That is always one of my favorite things about older electronics. One of my other hobbies is collecting antique computers, and the beautiful organic traces on 1960s DEC Flip-Chips always brings a smile to my face.

[Alejandro Paz (Germany)]

Do anyone has the circuit for the inverter/boost circuit of these calcs ?, just curious.