MR16 not working

[rm357]

With the three legged beasts like the regulators, mosfets, and triacs, I usually cut the leads off the device and remove the leads from the board one at a time. If you do that, you'll need to order replacement parts...

RM

[Jeffl]

One thing I always do when I build and Express (now, not when I first started) is install the heat sinks last.  I do all the self tests even before installing it.  Sorry, but this one is learning experience.  Even for the rest of us.

[btdb1969]

I took the 3 chips out, now I have 12v on the input and 1v on the output.... plus the power light is now on

[RJ]

Look it over very close for any solder bridges shorting out. It is rare to have a 7805 fail they are very tough as electronic parts go.

RJ

[dmaccole]

Look it over very close for any solder bridges shorting out. It is rare to have a 7805 fail they are very tough as electronic parts go.

Yes, but ... I had a problem building an MR-16 back in 2009 and the root cause was a bad 7805, shipped fresh from M.

So, while the possibility is slim, it isn't non-existent.

\dmc

[btdb1969]

I have looked at this thing about 10 times from different angles under a pretty strong magnifying lens and I dont see any solder bridges.
 Since it does have 1v on the output side and the power light DOES come on when i take the three chips out, could one of the chips be bad?

[chrisatpsu]

if too much solder is applied, sometimes it goes through the hole to the other side and can possible bridge there.

[RJ]

At that point I would try a new regulator. If it is a bridge drawing down to 1v I would expect it would be so hot you would have said something about it by now.

RJ

[btdb1969]

I ordered a desoldering pump, Im going to take the sockets off. I cant see under them to tell if there is a bridge there. Thank everyone for your help. I also ordered a new regulator...

[pk]

Before removing the sockets, I would use an ohm meter (DVM) and verify that adjacent pins are not shorted together.  Iremove the ICs) There may be pins that are intentionally connected together.  Post the pins you find shorted together and other members can help you.  This is a lot easier than unsoldering a socket.  Unsoldering a socket can potentially damage the board.

[RJ]

Unless the regulator is getting really hot like I said I would not expect a bridge and would replace the 7805 regulator.

RJ

[Dennis Cherry]

Are you sure it is a 7805 in that location.

[btdb1969]

yes, it is definately a 7805 in the location

[btdb1969]

It was the 7805, I replaced it and now I have an extreme rainbow working....Thank you everyone for your help in this, I definitely would not have had any ideas on how to fix this on my own.

[Jeffl]

Wahoo.  Congratulations.  Glad to be a part of the journey.