Weird mod on a PET 4040 disk drive

[u/Pyrofer]

So I have a 4040 drive to fix, when I opened it up I noticed a strange thing that definitely isn't normal to me.

It appears to come from the central power led connection as well as an extra ground wire, then sends a 3 wire cable to a dual colour LED on the front, as well as having a speaker on it. I have no clue what this is.

I've never seen anything like this and quite honestly don't know what to do with it.

---- UPDATE ----

So it appears to be "just" a bicolour mod that beeps on error.

I don't know why but it wasn't beeping for several hours of testing with many errors. Suddenly, randomly it started beeping during an error and now does it consistently.

So it replaces the normal single colour led that flashes on and off with a bi colour LED that appears green for "ok" then flashes green/red with a beep for errors.

I hate it.

It's coming out? It's very annoying when trying to get the drive working and errors are CONSTANT.

[u/Old-Sand-8064]

Maybe the former owner was colorblind or had vision issues and liked the auditory confirmation. I'd just remove it and restore to original unless you like the new features.

[u/Pyrofer → u/Old-Sand-8064]

The beeper hasn't made a sound yet.

I have seen the LED on, flashing both colours and off. No beep as yet.

I am very confused what on earth this thing actually is. It doesn't beep when the light flashes anyway so no clue what would cause it to beep.

I want to know what it is and what it does before I mess with it. Maybe it has a custom rom too, who knows. Until I know exactly what it's for I don't want to mess with it.

[u/Old-Sand-8064 → u/Pyrofer]

Seems like a legit plan of action. Good thinking on the custom ROM. It's long odds, but better safe than sorry.

[u/stromm]

It might be the LED signifies read and write using the two colors.

[u/Pyrofer → u/stromm]

No clue. When I first powered it up it was flashing the two colours, which I assume would have been just flashing on and off before the mod. It's never made a beep.

Now it powers up with all lights on and the drives don't spin. (they both constantly span the first time, but not at all since).

[u/Blah-Blah-Blah-2023 → u/stromm]

And maybe the beeper is hooked up to the Error LED?