ZX Spectrum Issue 4A: What does this mod do?

[Netaro]

Hello!

I've recently acquired ZX Spectrum, 16k version with issue 4A motherboard.
After opening the case, I've noticed that the speaker was missing, and instead this mod was inserted:

Does this mod do anything at all? If somebody wanted to simply remove the speaker, wouldn't removing it be enough?

[hatman72]

I believe that is an official Sinclair modification to the power section that was applied to the issue 3B as well. I don’t think it has anything to do with the speaker - that may have just been removed.

[1024MAK]

After opening the case, I've noticed that the speaker was missing, and instead this mod was inserted

That’s the official Sinclair power supply modification. Carried out either when the board was made, when it was returned for service or repair, or when a independent service/repair technician worked on the board. See by blog page for details of the last version of the modification.

The modification has nothing to do with the loud speaker. We can only speculate as to why it’s been removed.

Mark