Large Scale Central

a smoked sierra what did I do wrong?

Electronics Power and Sound
#1

Yep I bought, went to test and promptly blew up a soundtraxx sierra board steam V 1.1 throttle up. I have installed 3 of these for basic track power with no problems. Two ride in tenders that are shared between my steamers.

I’m still kicking myself and I don’t know what I did wrong.

I used the wiring diagram that has #9 to the positive side speaker and #10 to the negative, #8 and #7 went directly to track. I turned my test transformer on which is attached to a 24 " piece of track, applied power slowly and at about 1/4 throttle, 6-7 volts there was a pop and smoke.

Any idea on what I did wrong and can this be repaired?

#2

If you can see what component blew then maybe, but maybe not. As I understand it, the Sierra uses a board with traces in-between the top face and bottom face of the board. So if the inside traces aren’t damaged, and if you can carefully replace the damaged surface mounted component, then maybe it can be fixed.

This is why there is a warning in the manual about “testing” the board without a locomotive on the track. Some power supplies can put out too much voltage, when there is no appreciable load on them.

#3

Hi Todd… That’s a bummer… The Sierra boards are such good boards but when they blow, there is just no way to get them fixed. Soundtraxx stopped repairing them many years ago… They just couldn’t get the components they originally used…

Sounds like there was as voltage spike as David mentioned. The boards are so very sensitive to spikes and will not tolerate voltages much over 14 volts. Not sure what the top end is but I blew one using an 18 volt battery. I should have used the power resistor but got “lazy”… (http://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-frown.gif)(http://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-frown.gif)

#4

If that is the only wiring that was connected, there is no way anything should have blown, regardless of polarity.

That said, I have a Sierra Board where for no apparent reason one of the two lighting circuits just stopped working. This did work but now puts out no voltage and everything else still works fine.

Perhaps you had a wire strand creating a short at adjacent terminals or somewhere on the board itself.

#5

I have 2 diesels with Sierra boards and run them from a 24 volt supply. These are the old ones made for large scale.

Batteries are long dead in these and I should convert to super caps.

#6

Another “Magic Smoke” lesson…

#7

When you strip wires, hold the wire and striping tool away from your project. A hair of a wire can fall onto your board and cause total melt down. Ask me, I know. :slight_smile:

I toasted a Phoenix board that way.

#8

This is the wiring diagram I used. The bit that blew is the small rectangle block in the middle between 2 similar blocks that are between terminals 4 and 13.

I don’t know if that can be fixed. It looks like it is soldered right to the board.?

#9

That’s called a surface soldered component. from the diagram I can’t tell what it’s function is. It looks like you wired it correctly. Like others have said I think you had an over voltage spike. (https://largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-frown.gif)

#10

Can you post a picture of the burnt board and a picture or a working board ?

#11

It is such a small component that I don’t think it would show up in a photo John K. Under a magnifying glass it appears crusty and burnt.

Is this something that can be fixed? Would any of you electronic wizards want to take a stab at it?

#12

If you blew the black rectangle, the part # (written on the case) is C02M 2D. It connects to the left socket pin and has a line toward the pin side, so I believe is a diode.

If you blew the yellow rectangle, the # is 1560 R0601 (this last bit tiny and very hard to read and may not be correct) and the line is away from the socket. If it’s one of the other parts, let me know and I’ll try to read the #. But they are even smaller.

#13

Todd, I’ve got some spare Sierra boards I’m looking to sell if you’re in need of replacements. Two working boards, two non-working boards whose chips can be removed and placed in the working boards. (4 separate sound files total–EBT and three others, but I forget exactly which ones.)

Later,

K

#14

Kevin Strong said:

Todd, I’ve got some spare Sierra boards I’m looking to sell if you’re in need of replacements. Two working boards, two non-working boards whose chips can be removed and placed in the working boards. (4 separate sound files total–EBT and three others, but I forget exactly which ones.)

Later,

K

I’m always on the look out for affordable sound.

I also have another non working Sierra so maybe I will try to replace that little blown square. I will be sure to watch which side the lines are on if it is a diode. It would be great to get this working and into a loco.

#15

You will need a hot air soldering station to remove/replace the SMDs.

#16

Todd Brody said:

You will need a hot air soldering station to remove/replace the SMDs.

Well given that I had to look up what a hot air soldering station is I would say I’m not qualified to repair the board. LOL