LokSound up in smoke.

[diezmon]

So, after many other decoder installs, I thought I'd try my first sound decoder.   Picked up a ESU 73100 LokSound Select Direct Micro and ZIMO "Sugar Cube" Speaker.

Routed out my frame, took things apart, wired up the decoder(power and engine only), put on the track, programmed the address(using programmer track mode, so it was reading the decoder).  Then, I finish up, enter in the loco #, start it moving, and bam.. smoke starts coming out of the decoder.   

I'm sending back for a warranty fix, but what could cause that?  I took my time, verified the wiring, taped the motor leads and verified isolation with a voltmeter, and the decoder was readable when i put it on the tracks. 

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[daniel_leavitt2000]

It looks like a pretty solid install. My only guess would be that the motor contacts are still contacting the frame somewhere. Or maybe the front LED pads hit the flywheel?

[peteski]

Can you narrow down which component(s) smoked?  Maybe post a closeup photo?

Strange thing is that you were able to program it fine, and you said it even moved (motor ran) for an instant. Yes, it was most likely a short between something and something else.  Need more info.    Most likely the short was between the motor pickup strips and the rail pickup strips (yes, I see you used the Kapton tape, but I really, really dislike that installation method.

There are alternate ways to route the motor leads which are guaranteed not to cause shorts, and no dreaded Kapton tape!

Route the motor leads differently. This requires modification to the stock light board, but the motor leads will be safely away from the rail pickup strips.


Grind notches in the rail pickups. After installing the light board, the motor leads cannot  touch the rail pickups. No Kapton! 

[diezmon]

Can you narrow down which component(s) smoked?  Maybe post a closeup photo?

Strange thing is that you were able to program it fine, and you said it even moved (motor ran) for an instant. Yes, it was most likely a short between something and something else.  Need more info.    Most likely the short was between the motor pickup strips and the rail pickup strips (yes, I see you used the Kapton tape, but I really, really dislike that installation method.

Route the motor leads differently. This requires modification to the stock light board, but the motor leads will be safely away from the rail pickup strips.

Grind notches in the rail pickups. After installing the light board, the motor leads cannot  touch the rail pickups. No Kapton! 

I wondered about the motor contacts, although I checked with the voltmeter, and moved the leads a bit to make sure the tape was working.. thus my complete confusion. 

Your second picture is what I was thinking about doing, but I like the first idea better.   

It smoked right here, this little chip that's circled. 

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[tehachapifan]

...Your second picture is what I was thinking about doing, but I like the first idea better...   

(Attachment Link)

I tried the second idea before and found that the motor contacts simply fell/leaned inward more (spring action?) and still made contact with the pickup strip despite the notches. I believe this was on a Kato P42, which appears to be a similar setup (is that a P42?). I like the first idea though. Might try that next time.

[peteski]

It smoked right here, this little chip that's circled. 

Ok, that changes the diagnosis:  you have let the magic smoke out of the audio amplifier.  So, the short is somewhere around the speaker connections.  Either the speaker leads are shorted to each other, or shorted to something else.

[peteski]

I tried the second idea before and found that the motor contacts simply fell/leaned inward more (spring action?) and still made contact with the pickup strip despite the notches. I believe this was on a Kato P42, which appears to be a similar setup (is that a P42?). I like the first idea though. Might try that next time.

The notching only works when you then reinstall the Kato light board.  That board keeps the motor leads pushed outward, preventing them from contacting the track pickup strips.  It also keeps the track pickup strips in their proper locations.  The notch has to be wider than the slot for the motor strips in the plastic motor cradle.  That way, even if the motor pickups are pushed forward or backward, they will not contact the rail pickup strips.

[daniel_leavitt2000]

Ok, that changes the diagnosis:  you have let the magic smoke out of the audio amplifier.  So, the short is somewhere around the speaker connections.  Either the speaker leads are shorted to each other, or shorted to something else.

Since only one wire is soldered on the speaker connection, maybe the end of that wire touched the chassis or rail when testing or programing?

[peteski]

Since only one wire is soldered on the speaker connection, maybe the end of that wire touched the chassis or rail when testing or programing?

Good catch - I didn't notice that only 1 speaker wire was attached. Chassis on those models should be electrically neutral, but if it touched a live rail then - POOF!

[diezmon]

Good catch - I didn't notice that only 1 speaker wire was attached. Chassis on those models should be electrically neutral, but if it touched a live rail then - POOF!

ah sh1t, I'll bet that's what happened.   

I just checked.. the other end was stripped, so it could have easily touched something.