i've just aquired a DIP SIM MAC SE and on the main logic board I've noticed there is a blowen cap at CR1, which is located left of the 5380 SCSI chip, above C9.
Could someone tell me what replacement is needed and if there is a better resolution schematics? I've only found one which is very low res and very hard to read.
CR1 is not a cap. It's a 722 zener diode.
ok thanks for clearing that up. Do you know where I can locate a higer res schematics of the logic board?
Have you looked here?
Thanks for that. Its a little more readable.
What the voltage on the diode? Is it this?
I have a few etra SE mainboards, so I can probably pull one and see if there is a p/n or useful markings. I would expect it to be a 1N722. The '22' here is the rated voltage.
ok thanks. I've managed to remove the blown one but its was too far gone to see any markings on it to identify it.
I've found some diodes on amazon which work out cheaper. Can I just use any zener diode that has a voltage of 22v?
Delayed a bit. I will get you the data ASAP. I woul not advide you to use an inappropriaate part. The properties of diodes like this are rather important.
Hi, Did you manage to check this or are you still really busy?
Oh, bugger. In fact, I forgot entirely. TY for the reminder.
No problem. Let me know when you can. The darn schematics are so badly scanned they are near impossible to read.
I'll try this week. I ust checked in and saw that you still need this. Haven't been well of late, so everything is slow for me.
Sorry for taking an eternity to get around to this; here is a close-up photo of the board.
Note that on this board, it is above C5, not C9. Could you verify that marking?
As for replacing it:
The part is 1N4006 (1A, 800V), as far as I can tell. The p/n is partially obscured due to how it is positioned. I dook another loo at an angle, and 1N4006 seems right.
Here is a datasheet:
Either of those should be a good cross.
Sorry for the lack of reply. I managed to locate the diode and I've installed it. Mac booted up perfectly. Hard disk is alive still and has old data from a local council. I'll be investigating as soon as some RAM Simms repalcements arrive. My RAM was bad and I need !MB to load into the version of MacOS that is installed on the hard disk.
Thanks for all the help.