NeXT CDROM Restoration

If your CDROM drive spins up but never can read disks or is immediately ejected, you likely have leaking capacitors.

Drive Description

The NeXT CDROM is a rebranded Sony SCSI 1X CD drive (CDU-541-01). This drive was rebranded by other contemporary vendors as well. The following drives will contain similiar parts:

Vendor	Model	SONY Part #	ROM	Enclosure	Notes
Apple	AppleCD 150	CDU-541-25	APL 1.8g 1289	SONY, White	White faceplate, Board level incompatible with NeXT ROM
Apple	AppleCD SC Plus	CDU-541-22	APL-1.8d FEGA	Custom, White	White faceplate, Custom Apple Enclosure, Board level compatible with NeXT ROM
DEC	RRD42-AA	RRD42-AA	DEC 4.5d EEC3	SONY, Grey	Grey faceplate, 100% Hardware Match. NeXT ROM Compatible
NeXT	N3010	CDU-541-01	S-2.6a 76E7	SONY, Black	NeXT Black
Sony	CDU-7205	CDU-535-01?		SONY, White	White faceplate, low cost SONY interface (IDE-ish Drive), Logic board not compatible.
Sun	411	CDU-8012	SN-3.1e 4E5F	SUN, 411	Custom White faceplate, Custom Sun Enclosure, Board level compatible with NeXT ROM

All models are expected to fail in the same way. Note that there are differences in the onboard ROM. The DEC, Apple SC Plus, and NeXT drives are hardware compatible, and the ROMs can be swapped between drives. The AppleCD 150 is not ROM compatible, but the hardware is visually almost identical. ROM Replacement part: NM27C256Q-150

The proper NeXT ROM will remove the "MESSAGE REJECT RECEIVED" error messages at system boot. The messages can safely be ignored with no affect on functionality, but are not present in the NeXT implementation.

DEC ROM Example:


NeXT ROM Example:


Capacitor Replacement

Step 1)
Open the silver side of the CDROM. Remove the 2 screws in the back. Then remove the sliver cover. This will expose the logic board.


Step 2)
Disconnect the cables on the side of the drive. Be -very- careful with the brown ribbon connector. This part is extremely fragile and if you rip the cable you're likely going to have to scrap the drive. Use a small screwdriver to lift up and release the assembly.




Step 3)
Remove the logic board by removing the front 2 screws. Then gently lift out and disconnect the 2 remaining cables.




Step 4)
Replace the capacitors. I use ceramic capacitors to replace the electorlytics so that I don't have to worry about leaking caps in the future.

You will need:

Capacitance	Voltage	Tolerance	Temp	Dimensions	Part #	Quantity	Locations	Notes
10uF	16V	20%	125C	1206	GRM31CR71C106KA12L	2	Blue	Ceramic Replacement Part
47uF	16V	20%	85C	1206	C3216X5R1C476M160AB	3	Yellow	Ceramic Replacement Part
100uF	6.3V	20%	85C	1206	C3216X5R0J107M160AB	4	Red	Ceramic Replacement Part
					Total	9

Example with ceramic capacitors installed:


Optional:

Replace the capacitors on the front panel. I saw no problems with these caps, but if you want to be complete, remove the front panel.

Capacitance	Voltage	Tolerance	Temp	Dimensions	Part #	Quantity	Locations	Notes
100uF	6.3V	20%	105C			3
1uF	50V	20%	105C			1
					Total	4

Before re-assembling I recommend cleaning the laser lens as well. Take a cotton swap and high grade alchohol and gently clean.