On 24/11/2020 10:56:55, wrote:
Hi all,

I have taken a few more photos with our camera (had to find it and
charge it first as haven't used in a couple of years). They are in
the same location as the others
https://drive.google.com/drive/folde...5D?usp=sharing

Trying to get a photo of what is written on the chip is next to
impossible. So best I can make out the following is written on the
top of the 2 chips Chip 1 - 25FS406 06 2PHON

Which is a Sanyo Serial Flash memory as suggested:

https://pdf1.alldatasheet.com/datash...LE25FS406.html

On Semi bought Sanyo and not sure how to access the old Sanyo parts
directly.

Chip 2 - Winbond 25040BW607 1244

Which I haven't looked up but assume it is a volatile memory.

In terms of the circuit board. As has been mentioned above, it looks
like it goes pin 7 - missing component - pin 3 of same chip pin 7
- hole in circuit board but nothing the other side.

There is no writing on the missing component that I can see so I
assume it is a resistor? Checking the resistance with a DMM I get
1880 in both directions.

Which does suggest a 1.8k resistor. Possibly a bit lower in value than I
would have used and higher tolerance. 1% resistors are the norm. It
costs more to put them on a PCB than the actual cost of the component.

Based on this and from what I understand from the various replies, it
sounds like this is to ensure the chip doesn't go into reprogram mode
and therefore safe enough for me to test the board without the
component. Is this correct?

What it does do is ensure the default level is write-protect, so that if
there is a corruption in the micro the memory won't be overwritten.

Writing to a Flash memory is non-trivial, with specific codes being sent
to enable writing, even when the nWP pin is high.

I would say it is normally safe, but would be safer with the resistor
fitted.