S+ SAS RS232 interface schematics
poppo:
So people don't have to wade through that other thread (that has some wiring errors early on), I have put the schematics here
Disclaimer: I made my best effort to ensure that the factory board schematic is correct. Nothing will blow up your machine, but I can't guarantee it will work as I have not actually built it. I used a factory board to trace everything out. It is up to the user to have some knowledge of electronics to assemble either of these. For example, knowing which way to put in an LED, and the correct polarity of the regulator capacitors. If anyone wants to add to or modify either of these, all I ask is that you let me know what you plan to do first.
That said, the first schematic is of the factory RS232 SAS board. Since J82 and J2 don't have pin #1 labeled, I have drawn them as they are on the board with J82 at the top, and labeled them accordingly. I have included the pin to pin wiring for those that may be lucky enough to find one of these boards and just needs to hook it up. There were several errors in the early drawings in the original thead, so these have all of the corrections. I have shown J4 and J9 that are on the motherboard as you would be looking at it from the door of the machine. I drew lines on the pins that are used. Note: If you use J9, be sure to use pin 2. If you use pin 3 by accident, you will fry your board as it has 12vac on it.
The first schematic is mainly for someone ambitious enough to want to build one like the factory. :79-
For those who want a quick and easy interface, the second one will do the job. I have built two of them and they work just fine. As I noted in the other thread, there are pre-made MAX232 boards on e-bay for about $4.00 that should work. But I don't yet have one to verify it (but have a few on order). This option requires that you supply a REGULATED +5V to the MAX232 (and motherboard). You can often find these type of wall warts on stuff like USB hubs etc. But you must make sure it is 5V regulated or else you need to build your own 5v regulator. The important thing with this option is that the +5V supply ground must be tied to the MAX232 (of course), but it also goes to pin 2 of J4, and it should also go to chassis ground. This is because the MPU normally gets it's ground for this part of the circuitry from the factory SAS board which gets it from pin 1 of J9. And if you don't supply a common ground, it may not work right, or be intermittent.
You may also notice that the MAX232 on my simplified interface is wired slightly different than the factory board (a few of the capacitors). I don't know why there is a difference, all I know is that they both work.
<edit> 05/11/11 Fixed more minor errors on the IGT board.
Foster:
I will add mine that works.
poppo:
Quote from: Foster on March 02, 2011, 01:12:43 AM
I will add mine that works.
Go for it. :89- I was mostly concerned with someone making modifications to these that could result in :98-
stayouttadabunker:
Hey! What's all those triangles and squiggly lines for? :96- :200-
Just kidding...Great great stuff guys!!!
The wiring diagrams and schematics of the year! :3- :244- :131-
poppo:
Quote from: stayouttadabunker on March 02, 2011, 03:13:54 AM
Just kidding...Great great stuff guys!!!
I have to give a special thanks to Bunker for smoke checking his factory board so that I could get a closer look at it. :209-
Sorry, couldn't resist. :96-
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