CB 280 AC adapter help

[cmkimball88]

Hello all! I've been using CUBLOC for about 6-8 months for school and this is the first time I've had a problem that I cannot solve.

I'm working on a lab for a class and I have everything wired up and plugged in but when I switch on the power, the green LED blinks for just a moment and a medium-high hum comes from the AC adapter. I've unplugged it from the wall and tried it in different outlets, I can't get it to work. This is the same adapter that came with my kit and I've never had this problem before.

Does anyone have any suggestions or hints? I emailed my teacher but I'm reaching out to anyone who might have a clue as to what's going on. I have several pictures I'll email if you request them of the set up but I'm 98% positive my set up is just fine.

Thanks in advance for the help!

[sci_prez]

It sounds like your adapter is feeding into a direct short circuit.

Disconnect the AC adapter from your CB280 and measure the voltage of the adapter. If its normal, you have a short somewhere on the CB280 board. Have you recently added circuitry? Or have some of your connections gotten changed?

Do you have a circuit diagram of the way you have things connected? That would help with identifying potential trouble spots.

Tom

[cmkimball88]

I measured the voltage from the adapter and it's reading at 23.9V which is close enough to 24V for me.

I exchanged a wire for a resistor but no connections have changed. About an hour ago, P40 popped and smoked (white smoke) but I turned it off, added a resistor to the bread board, and everything was fine. LED's were working and turning on and off. Not to sound stupid but that couldn't be the problem because wouldn't it stop working immediately after that? Or could it have been a delayed reaction?

This is a link to pictures of my set up:
http://s235.photobucket.com/albums/ee14/jedichick070588/Temp/
Hopefully that works. The idea for the lab is to get 4 LEDs to flash sequentially when P32 is activated. When P33 is activated, the lights stop and a 5th LED turns on. I've been testing different ladder logics and I was trying to figure out why P32 would turn on but P33 wouldn't turn on when P40 popped.

I unfortunately don't have a circuit diagram but I can draw one up if you need one.

Thank you for your help.

[sci_prez]

I agree, it sounds like the adapter is fine.

That smoke from P40 sounds very suspicious and may point to some other, hidden damage. The transistor pack has several devices inside and one bad one can affect the others.
The schematics for the board are on the website and may give you some insight into the fault.

You have to be very careful with the connections to/from the cb280 board. It is so easy to get a power and ground connection mixed up.

Cheers,

[cmkimball88]

Okay, thanks for the help. That's pretty much what my teacher told me. Because it's hard to exactly diagnose what went wrong, he's going to help me in class.

Thanks again for all the help!