Odd HP-35 Red Dot

[aj04062]

It is clear to me this went back for rework. I am guessing that the 7303 ROM was replaced to fix the "bug" which it does not have. The solder job on the board is excellent.

Before I removed the rear label, it does not look like it was ever molested.

(09-28-2017 12:15 PM)jebem Wrote:  

(09-27-2017 11:55 PM)aj04062 Wrote:  Well I picked up this Red Dot the other day. I am confident in saying this even though it looks like a V4 HP-35.
...
To my surprise it is an early board (note 03-72 date plus 1211 marking).

It's always a pleasure to look to these machines internals and reconfirm the high quality of the 70's technologies.

Mine is not a red dot for sure.
Also it has got a PCB date code of 40 73, and one of the ROM ICs is marked with 7344 (1973 week 44):
http://4.bp.blogspot.com/-pyNvbIEGkAY/VC...M_7888.JPG

But looking to your PCB, it seems that at least one of the ROM ICs is marked as "7303" (1973 week 03).
Would this still qualify it as a red dot?

Can you check if some of the ICs solder joints where manually re-soldered?
If yes, then probably someone have rebuilt it in 1979....

Edited to add this:
Does your machine have the famous "exp(ln(2.02) = 2" bug of the early firmware?