Help identifying a diode in an Apple CD300/Sony CDU561

[shadedream]

So I decided to open up my Apple CD300 to get around to recapping it. The drive was working fine previous to opening it, but I discovered this:



Anyone know where I can find some schematics or somehow find the value of that fried diode? Referencing Bruce's images tells me that it's D402. Only markings on it there are "_ B":

https://recapamac.com.au/wp-content/uploads/2020/03/sony_cdu561_cdrom_logic.jpg

 

[shadedream]

Just giving this a little bump in case anyone can give me any direction on figuring out a replacement for this, would love to get the drive back to a healthy condition.

 

[nekonoko]

I don't have any additional info, but I have a spare CD300 logic board (recapped with tantalums) if that's helpful. I rescued it out of a drive with a bad laser and don't need it for anything.

 

[shadedream]

Will shoot you a PM, I'm still curious about repairing this one though if possible as well.

 

[robin-fo]

Here is a closer photo of this section

 

[zigzagjoe]

Taking this from the inverse direction: the chip it connects to is a PROM, pin 1 is Vpp (programming voltage) which is used when programming, otherwise is advised to be Vcc.

The side nearer to the caps I'd assume is a 5v rail (continuity test it to confirm) and the other side should go to pin 1. I imagine any diode would be fine.... though it does beg the question of /why/ it burnt up, as it should see basically no current flow unless something else connects to it on the bottom of the board.

disregard, i was mistaken

 

[robin-fo]

I have another board with the same diode burnt, so appears to be a common problem

 

[zigzagjoe]

I have another board with the same diode burnt, so appears to be a common problem

looking at it closer it definitely isn't going to pin 1 on the ROM, your picture is more easy to see what is going on. Can you trace what that connects to?

 

[robin-fo]

I believe it is connected to pin 32.. but can no longer confirm as I just removed everything from my desk..