Board assy & test for power

Barry_D · Post by **Barry_D** » Thu May 20, 2004 11:33 pm

Hello all,

I have two questions. First, can I use a 12v power supply for testing my board that looks like a typical cell phone charger? The label reads - Output: DC 12V 300mA... Of course I'd check polarity before connecting it to the board.

And second, I think I may have soldered my Q1, 2, 3, 5, 6, 7, and Q8 transistors wrong. : ( I know Q4 is right, but my others aren't oriented like Brent's board pictured. I have all of the transistors center leads going to the #1 position at each location.

Anyone feel free to jump right in if you'd like. My 1st power test during assy was fine using a 9v battery, but now that it's completely assembled I don't want to power this guy up a second time and see smoke!

Barry

Post by **brentp** » Thu May 20, 2004 11:59 pm

Which way is the flat side of the transistor facing?

So you may need to remove and re-insert the transistors. Do it carefully using de-soldering braid, so you don't damage the traces on the board. If you don't have any you can find it at radio shack. The stuff works really well and will leave you with clean holes so you can re-insert them.

Good luck,
Brent

Barry_D · Post by **Barry_D** » Fri May 21, 2004 12:14 am

Thanks for getting back to me fast Brent,

The flat side on the transistors are facing to the right. So should I rotate them all one position clockwise except Q4? I DO have some de-soldering braid. I know how well it works.

And what about the power supply I mentioned? I noticed hooking it up to my digital multimeter it fluctuates as high as 15.52 volts. Is that okay? It seems like it would be since alternators don't maintain a constant 12 volts...

Your thoughts?

Barry

1974 2002 BMW wide body w/many mods...
complete engine rebuild, f.i/turbo/MegaJolt
& MegaSquirt conversions starting now!
(=oo=)
Rock on Brent!

Barry Durham
barry@BMWupgrades.com
501 227-4365
http://www.BMWupgrades.com/
Coming soon...

Paratime · Post by **Paratime** » Fri May 21, 2004 12:53 am

The voltage regulator LM2937 is capable of regulating input votages of up to 26 volts as well as reverse polarity, so the floating voltage of the wall wart is no problem. Here is it's data sheet:

http://www.national.com/pf/LM/LM2937.ht ... escription

I am using a similar supply for mine with no problems.

The 2N2222 transistors should be inserted with the flat side facing the bottom right corner, looking at the board with Q1 at the top, and Q6 at the bottom. The center lead should be bent slightly toward the flat side, and it will drop right in.

Barry_D · Post by **Barry_D** » Fri May 21, 2004 3:01 am

Thanks Paratime,

I'll de-solder, re-orient & re-solder the transistors this weekend. Next comes the fun part with software, programming, and finishing my front trigger wheel and sensor mounting bracket.

Hey all, who's going to design a graphic that we can turn into a decal for our cases?

Really! We should get a decal done. I do web page & graphic design, I suppose I could put together some samples and everyone could give their input, then vote on the best design.

Thoughts?

Barry

1974 2002 BMW wide body w/many mods...
complete engine rebuild, f.i/turbo/MegaJolt
& MegaSquirt conversions starting now!
(=oo=)
Rock on Brent!

Barry Durham
barry@BMWupgrades.com
501 227-4365
http://www.BMWupgrades.com/
Coming soon...

Post by **brentp** » Sat May 22, 2004 5:07 pm

A graphic would be cool- and I'd love to see your samples!

Autosport Labs