To be as close to the original equipment, I recommend that you should buy the replacement transistor from ebay, it is not that expensive. As you are not greedy, the price should be ok and you get the joy of replacing it yourself.
Joy of fixing your own charger is priceless.
Happy holidays.
Based on the datamath webpage there were ICs around with more than 1000 transistors as early as 1967 used in TIs calculators prototypes.
But it's not clear if this is a single chip or all three had together 1000 transistors and the exact chip is not mentioned.
I've done some further research on the CalTech prototype. There is a patent available: Patent US3819921 which describes the calculator prototype from TI.
Figure 15, 16, 17 and 18 show the logic of the four implemented ICs. The biggest one in figure 15 has 151 NAND gates. Figure 20 shows the construction of a single NAND gate. As can be seen, they are made using 6 PNP and 2 NPN transistors, so each NAND gate needs 8 transistors.
For the chip with 151 gates this results in a total transistor count of 1208.
Now that patent was filed in 1971, which is later than the original prototype, so I'm not 100% sure that the early prototype used already this chip. The patent mentions an application number 671,777 filed in Sept. 29, 1967. I've found a document where the original patent application and it's claims get discussed but as the whole description is not available, it's hard to say if the ICs were altered during the 4 years. Claims 15 and 35 speak of a "large plurality" of same gates, so that might be an indication that the ICs were already the same.
Based on the computer history webpage in 1965 there was a MOS ROM with 1024 bits developed from General Microelectronic. As a MOS ROM it would have needed 1 transistor per bit (if I'm not mistaken), so that chip should have had 1024, sounds like maybe the first as only 2 companies were working on MOS at that time (based on this). I haven't found a supporting source for that claim though.
In mid- 1965 only two companies were producing MOS ICS — General
Microelectronics and General Instru- ment—but interest in the new
process was high.
Also mentioned in the Electronicsmagazine Special Commemerative Issue on page 251 is a MOS device for the military containing 968 components. Probably not all of them are transistors, but it seems like it was doable in 1965. Reading further in that document they claim that a 1024 bit ROM was announced by Philco-Ford in 1968 (page 271):
A 64-bit MOS memory organized into 16 4-bit words was offered by
Fairchild. A year later Philo-Ford announced a 1,024-bit ROM.
Best Answer
I'm still looking for a good cross-section SEM image or similar representation. Until then let's see how close we can get.
UPDATE: Newest results at the end!
Worth watching in YouTube: Engineering History Interview with Ted Hoff
PDF DataSheet: 4004 Single Chip 4-bit P-channel Microprocessor
PDF DataSheet: MCS-4 Microcomputer Set
See Figure 6 (page 34): The_MOS_Silicon_Gate_Technology_and_the_First_Microprocessors
See Figure 6 (page 12): The Intel 4004 Microprocessor: What Constituted Invention?
LAYOUT and Mask Layers: Complete Artwork, Schematics, and Simulator for Intel MCS-4 (4004 family) microprocessor chip-set: "Together again after 38 years!" and also The Intel 4004 after 44 years! 2015 Progress Report
One of the important elements that needs to be captured in the SEM images to fully answer the question is the use of self-aligned, poylsilicon gates, rather than the real metal (aluminum) gates used previously. The M in MOS (CMOS, PMOS, NMOS) stands for metal and it's important to remember it used to really be metal!
From The Intel 4004 Microprocessor and the Silicon Gate Technology:
The article is quite long, here's another excerpt:
From The Intel 4004 Microprocessor and the Silicon Gate Technology
Paywalled link to IEEE Transactions on Electron Devices ( Volume: 16 , Issue: 2 , Feb 1969): https://ieeexplore.ieee.org/abstract/document/1475473 Researchgate: https://www.researchgate.net/publication/3068458_Insulated_Gate_Field_Effect_Transistor_Integrated_Circuits_with_Silicon_Gates
Verified Schematic: http://www.4004.com/assets/redrawn-4004-schematics-2006-11-12.pdf
From a 2011 post Understanding the Intel 4004 found in IC Reverse Engineering and Other Adventures
Top view optical microscope view, partial deconstruction, one pin interface:
Chip select output (?) for external 4002 RAM:
From The Intel 4004 Microprocessor and the Silicon Gate Technology :
From Current 4004 Display at Intel Museum (2014) & Introductory Note
Screenshot from the YouTube video The Designer Behind the First Microprocessor: Federico Faggin
From The Story of the Intel® 4004:
I Found Something!
From I found some screenshots of similar PMOS device fabrication steps from
Check the following for Cross-section SEM images:
Paywalled: Silicon gate technology F. Faggin and T. Klein, Solid-State Electronics, 13, 1125 (1970)
Paywalled Metal-nitride-oxide-silicon field-effect transistors, with self-aligned gates J. C. Sarace, R. E. Kerwin, D. L. Klein, and R. Edwards, Solid-State Electronics, 11, 653 (1968)