On 22/11/2020 19:20:51, Lee Nowell wrote:
Hi all,

I have a dead HDD I am trying to fix for a friend. I have a
replacement PCB to see if that sorts it but it involves
desoldering the ROM chip from the original board and soldering it
on to the new board.

When I was taking the ROM chip off the new board I inadvertently
took off a nearby component.

I have uploaded a couple of pictures here
https://drive.google.com/folderview?id=1mvAgXH2
psjYEIl7_ErrHKdEpucKCd15D--

One photo shows the new board with the original ROM soldered in
place and a red arrow showing where the missing component is. The
other photo shows the original board with the ROM removed but you
can see the component that is missing on the new one - it looks
like a black bar.

I have been in discussion with the PCB supplier who specialises in
these boards as well as fixing them. He said that this component
is not critical and I should try the PCB without it.


Couple of questions
1. Any idea what the component is? A resistor?
2. On the new board you can see that the pads the component sits
on are now not connected as it would be through the missing
component. If the component is not critical, my guess would have
been that I at least need to connect the pads together?
3. Another option is to take the one off the original board and
use that. Is that viable with a regular soldering iron? Also,
depending on what it is I guess it could have a particular
orientation which adds more complexity

The pinout seems consistent with a SPI Serial Flash memory where pin 3
is a nWP or write protect pin.

There might be a internal block protection bits that is used in
conjuction with this pin.

If the device is pre-programmed then the level shouldn't matter,
otherwise the pin has to be held high and I would expect the resistor is
passively holding the pin low to prevent inadvertent programming.

Without more details of the device the above is an educated guess.