HP 9100A/B How many transistors and diodes?

[Kiwi Engr]

I'm writing an essay that traces the evolution of computers. To compare the HP 9100A (or B) to early microprocessors, I need to know the total number of transistors and diodes used in its construction. If anyone has researched this, please share the number here.

Looking at published photographs on MoHPC, I arrived at 1100 diodes and 210 transistors, which is probably a significant underestimate.

Looking at DrARD's hand-drawn schematics 5.0 (parts 1-4), I obtained 5168 diodes and 792 transistors.

FYI, here's my HP calculator collection (such as it is):
1 x HP-35 (Ser. No. 1302A24988)(OK)
1 x H-35 (OK)
1 x HP-65 (Ser. No. 1333A13123) OK, reader pinch roller refurbed

HP-65 magnetic cards:
Standard Pac, cards STD01A to STD19A (19 cards)
1 Abrasive head cleaning card
11 unused blank cards
9 used cards containing programs (no clipped corners)
(A grand total of 40 cards)

2 x HP 9810 (non-functioning, but hoping to make one good one from the parts. Think about buying an HP TTL logic comparator from Ebay to assist with that)
Various Model 10 ROM modules for the 9810A:
Mathematics 11210A Ser. No. 28047
Mathematics 11210A Ser. No. 27508
Statistics 11214A Ser. No. 08025
Peripheral Control Printer Alpha 11266A Ser. No. --------
Printer Alpha 11211A Ser. No. 23129
Keyboard overlays (t.b.d.)

1 x HP-9815A (Ser. No. 1623A05733) (OK)
DIV 4000, Shipped 10/5/78
Installed Options: 001 (memory expansion), 002 (I/O buffer)

2 x ring-bound Manuals for HP 9100A/B
Various other HP manuals, and odds and sods (t.b.d.)

Any help with the 9100A/B diode and transistor counts will be greatly appreciated. Thanks!
Al (Kiwi Engr)

[Kiwi Engr]

I only just discovered that my "The Museum of HP Calculators DVD" has an official HP service manual for the HP 9100A/B models. Edit: Unfortunately, it covers only the CRT deflection and power supply circuitry. I am guessing, but it would appear that board swapping may have been the preferred repair method.

In passing, I note that my Sept '68 issue of HP Journal says the following:

p.17 Several thousand diodes and transistors. <-------Implies probably fewer than 10,000 combined total.

p.20 1,000 diode gates in the main ROM. <-------At three diodes per gate, on average, this would imply 3000 diodes.

[teenix]

(12-20-2024 12:15 AM)Kiwi Engr Wrote:  p.17 Several thousand diodes and transistors. <-------Implies probably fewer than 10,000 combined total.
p.20 1,000 diode gates in the main ROM. <-------At 3 diodes per gate, on average, this would imply 3000 diodes.

A lot of fun trying to find a faulty one ;-)

[brouhaha]

The inductively coupled PCB ROM memory in the bottom of the machine contains 512 diodes, one per memory word. While that memory stores 32,768 bits, there are no electronic components (or even ferrite cores) replicated on a per-bit basis. It is an amazing technology developed specifically for the 9100, and then immediately obsoleted.

[Kiwi Engr]

Two other memories:
the braided control logic microinstruction ROM (64 x 29-bit words) and
the 6 x 16 x 23 coincident current magnetic core memory, which used wide-temperature-range lithium cores.
These are equally amazing, although less experimental than the large PCB ROM!