68kMLA Classic Interface

This is a version of the 68kMLA forums for viewing on your favorite old mac. Visitors on modern platforms may prefer the main site.

Click here to select a new forum.

Help identifying a diode in an Apple CD300/Sony CDU561

Posted by: shadedream on 2023-07-22 12:14:47 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

Posted by: shadedream on 2023-07-26 15:42:24 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.

Posted by: nekonoko on 2023-07-29 07:54:17 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.

Posted by: shadedream on 2023-08-01 18:11:54 Will shoot you a PM, I'm still curious about repairing this one though if possible as well.

Posted by: robin-fo on 2023-08-16 12:43:07 Here is a closer photo of this section

Posted by: zigzagjoe on 2023-08-16 13:17:40 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

Posted by: robin-fo on 2023-08-16 13:50:33 I have another board with the same diode burnt, so appears to be a common problem

Posted by: zigzagjoe on 2023-08-16 14:00:36 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?

Posted by: robin-fo on 2023-08-16 14:45:26 I believe it is connected to pin 32.. but can no longer confirm as I just removed everything from my desk..

1