OT: rs232 homemade isolator

nomore25s

Well-known member

Donor 2011
Joined
Jan 27, 2009
Messages
2,052
Reaction score
463
Location
Kentucky
Okay, I know this isn't arcade related, but someone on here knows the answer - any links/pointers [digikey, etc] are appreciated.

I have had my 2nd lightning strike destroy a serial/rs232 device in my house. I was looking at something like this:

http://www.usconverters.com/index.php?main_page=product_info&cPath=65&products_id=187

Can anyone point me to the "fuses" or "optical diodes" or whatever is used in these? At $34, they're only slightly cheaper than the device itself.

I was hoping to just wire up my own on RX/TX/Ground lines.
 
Last edited:
The optoisolators will keep any 232 lines from conducting the strike, but are you sure the 232 lines are how the power got through? It could be, but are you sure it isn't something on the power side that caused the damage?
 
The optoisolators will keep any 232 lines from conducting the strike, but are you sure the 232 lines are how the power got through? It could be, but are you sure it isn't something on the power side that caused the damage?

Well, both devices are on APC UPSes. One is obviously a computer, which I guess it could be entering via the ethernet (no other network devices seem affected). The other device works fine, except for the rs232 interface.
 
Lightning is a funny beast. If it can jump 2000+ft, a little opto-isolator isn't much of a gap.

We took a hit to a tree in the yard last year, and none of the devices directly connected to the outside were damaged (i.e. phones, cable modem, router). But several devices on the LAN further downstream lost their ethernet ports.
 
Lightning is a funny beast. If it can jump 2000+ft, a little opto-isolator isn't much of a gap.

We took a hit to a tree in the yard last year, and none of the devices directly connected to the outside were damaged (i.e. phones, cable modem, router). But several devices on the LAN further downstream lost their ethernet ports.

Yea, I've experienced the same thing (the semi-randomness of lightning).

This is the 2nd time I've lost this particular device and thought I'd try something. It clearly is overly sensitive to surge.

In the same strike (this latest) I lost a DVD player/burner, and the TWO hdmi connections to the lcd tv it was hooked up to (tv is fine with the component and composite connections). Also took out the safety sensors on both garage openers. It also tripped 3 breakers in the panel.
 
How about a whole house surge protector?

Bill
 
Yea, I've experienced the same thing (the semi-randomness of lightning).

This is the 2nd time I've lost this particular device and thought I'd try something. It clearly is overly sensitive to surge.

In the same strike (this latest) I lost a DVD player/burner, and the TWO hdmi connections to the lcd tv it was hooked up to (tv is fine with the component and composite connections). Also took out the safety sensors on both garage openers. It also tripped 3 breakers in the panel.

I guess the optos are the next thing to try. I'm afraid you might be getting problems just from the EMI of the strike coupling into your electronics. You might want to make sure you're using shielded 232 cables (including metal housings - not plastic!). Verify that the chassis on both ends are grounded and that the outer shells of the 232 connectors are grounded. That will help if it's an EMI problem.

Also, if you took a hit hard enough to kill equipment, you should probably think about replacing all your surge suppressors - they pretty much all use components that degrade when hit.
 
Back
Top Bottom