ssbowtie1

I want to build the max232 or max233 inferface for my 88 IROC. Here's the list of the parts that I have put together so far.
max232
------
1 max232 chip
1 7805 5v regulator
6 10uF capacitors
9 10k resistors
4 2n222a or 2n3904 NpN transistors

max233
------
1 max233a chip
1 8.2k resistor
1 33.2k resistor
1 1N5820 Diode
1 300 ohm resistor
1 4.7uF capacitor
1 5.1v zener diode (1N5231B or 1N4733A)

Is there anything else that I am missing or something that is wrong. Anyone know what the right part number for the zener diode is. The wattage is not shown, just the voltage. Thanks for any help.

super83Z

I was also wondering what the wattage was. Can anyone help out?

Craig Moates

Wattage should be very low, maybe 30mA total current if I remember. I did some tests at one point.

I'd suggest the following for a parts list:

(1) 78L05 (smaller package)
(5) 1uF caps (can use small tantalum dipped dudes)
(1) 0.1uF cap (same deal)
(1) Max232 chip
(8) 10k resistors (1/8 watt doodads good & small)
(4) 2N3904 or 2N2222A xistors
(5) 1N4148 diodes
(1) DB25 Male solder-cup
(1) DB25 Female solder-cup

I'm putting together an updated schematic, maybe be done in a couple days, which reflects the above list of parts and how they go together.

Anyways, hope this helps rather than confusing!

-Craig

ssbowtie1

Hi Craig, so the parts list looked right besides needing a low wattage zener diode? Please keep us updated as to the new schematic that your coming out with. Thanks

Craig Moates

For the 233 circuit, you still need the voltage regulator and a couple caps.

For the 233 circuit, I found this to work:

I1 = MAX233
C1 = 4.7uF Axial
C2,C3 = 10uF Axial
R1,R3,R4 = 33kohm
R2 = 300ohm
R5 = 10kohm
D1 = 5.1V Zener (1N4733)
D2 = Schottky Barrier Rectifier (1N5820)
U1 = ECG977 5V Regulator 78L05
(this is one of those 'private' designs...)

I'm sure some variation will also work. If you look at the traces, the red is on top and the green is on the bottom.

Have phun!

-Craig

ssbowtie1

I think that I will get the parts list that you supplied on your last post. The only question is, do you use a max233 chip or a max233a chip? Is that why this schematic is different, because you used a max233 chip? Thanks alot for your help.

super83Z

SSbowtie1 I hope you understand that cuz it just looks like an old Atari game to me.

Craig Moates

Well if you liked that, you're gonna love this...

With AKM's permission, I present the following:

Check out http://www.mindspring.com/~amattei/aldlif.jpg

Also, here's my rendition (and there may be some errors) of an 'as-built' Ruse/AKM unit:

b92z28

N/M

bennyhonda

Back to top for a few more questions.

I built the max232 cable per the above schematic, however comparing it the other schematic on moates site, it was slightly different.

First, the polarity C2 and C5 are different. I am using polarized caps wired as shown above, so will they work as installed or do I need to change their polarity?

Second, it looks like the circuit is powered by both the serial port and 12V from the car (cig. lighter). Does the circuit really need both or can I choose one or the other?