VB921 Testing and another question.

matt325is · Post by **matt325is** » Thu Jun 01, 2006 3:29 pm

Hey, is there a way to test if my 3 VB921s are burned up or not? Like diode testing and such? Last summer I was fooling around with them and forgot to invert spark output, and they got pretty hot, I immediately shut off the car. Now I'm actually installing everything now that I have time, and the wheel decoder is sending a tach signal, however my coils are not firing.

ALSO, do the LEDs and necessary resistors for the LEDs need to be installed for the spark outputs to work? I disconnected the LEDs a while ago, and am thinking this may be a problem. I'd like to rule out any extranious variables before I go and buy other things. Any other ideas would be helpful.

Thanks in advance.

matt

PeterCip · Post by **PeterCip** » Fri Jun 02, 2006 7:00 am

Matt,
I went through all the possible testing for my VB921s.. and they all proved that the driver should have been fine. When it came down to it, it wasn't. Setting it to non-inverted for a run made the driver more ceceptable to over heating and or turning off completely. Do yourself a favor, and spend the 15 dollars for new ones. I nearly scrapped the car out of frustration.. and it came down to a 5 dollar part

PM me at e30tech if you have any specifics.. Oh, and i can't remember the tests.. sorry. What i can tell you is, if it is running very hot, your dwell is to high, or the driver is junk. I'm running 3.5 ms on the electronic MSD SS coil.

Pete

P.S. I'm running around, sorry for the shitty grammar ;)

matt325is · Post by **matt325is** » Fri Jun 02, 2006 2:52 pm

Thanks Pete, last night I got fed up with everything and bought the v3.0 board and 2 new vb921s. I'll start from anew, my old 2.2 board was beat to all hell from all the mods I did to it, it was a pain troubleshooting everything, and when I came down to it, I just wanted everything onboard... I had a daughterboard that fit in the MS case, but it was a SQUEEEEEZE, had the decoder circuit, vb921s, and boost control circuit on it, it'll be nice to have the proto area built into the main board, I cant wait for early next week!!

thanks again.

matt

MegaScott · Post by **MegaScott** » Fri Jun 02, 2006 3:01 pm

matt325is wrote:Thanks Pete, last night I got fed up with everything and bought the v3.0 board and 2 new vb921s. I'll start from anew, my old 2.2 board was beat to all hell from all the mods I did to it, it was a pain troubleshooting everything, and when I came down to it, I just wanted everything onboard... I had a daughterboard that fit in the MS case, but it was a SQUEEEEEZE, had the decoder circuit, vb921s, and boost control circuit on it, it'll be nice to have the proto area built into the main board, I cant wait for early next week!!

thanks again.

matt

Matt if you need any VB921's I have a few I can sell you at cost, I can drive down from Monroe and meet you half way. PM me if you need 'em.