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UPDATE on Lights causing LM-3S to overheat?

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kellanphil:
What was the result?

CPRail:
Sorry guys, we had the first really nice days of spring here on the weekend (FINALLY), so no train activity due to being outside enjoying the weather! Of course, it was gloomy and snowy all day yesterday in punishment. Mother Nature is a harsh mistress...

I'm doing the tests tonight and will update in the morning.

CPRail:
Here are the results (see photos). The grey items on the bottom of the board sure look like resistors to me, but I'm not an expert - I only play one on TV.  One location is marked R1.

All running was done on test rollers as I don't have a continuous loop of track. Throttle was set at 75% for all tests. Load was set to about 25-30% on the HC. There was a 5 minute cooling period between the first run (in reverse) and the subsequent run (in forward). I removed the shell immediately after each running test to check temps.

Test 1 was 15 minutes in reverse, headlights/gyralites were off.

Test 2 was 20 minutes in forward, headlights/gyralites were on.

After Test 1 the grey resistors where cool to the touch, the LM was slightly warm.

After Test 2, the front grey resistor was rocket hot (headlight), the rear was uncomfortably warm (gyralites), the LM was noticeably warm - you could feel the heat from the outside of the shell.

While you can see the LM temperature increasing, I suspect if I had an actual load and was able to let it loop, it would increase faster.

Next steps?

gregeusa:
OK, just checking we are on same page. from april 7

you replaced all the original incandescents with LEDs, and you added resistors.

(no value was given for the resistors!)

in the same post you say the LEDs were not hooked up when you tested with a meter...

right here, those resistors on the board overheating without the LEDs connected makes no sense whatsoever...

if this is true, if you have the right resistors that connect to the function outputs, your board is damaged..

I think we need pictures of the board, with the "resistors" circled and verified what they are connected to..

Greg

gregeusa:
update, I could not see the pictures when replying...

OK, your components hooded the the LEDs are resistors, not inductors...

they have 5 bands, so they are precision.. what is hard is to read the sequence, since the tolerance band is not the typical gold or silver (of course since they are high tolerance, i.e. 5% or better)..


brn-brn-blk-blk-brn  (100 ohms)  (cannot read the other way, the first digit cannot be 0, i.e. black)

so 10 ohms times 1 = 10 ohms...

if that is right (measure with meter), no kidding you have the wrong resistors!

what is the common voltage? (not mentioned) but if 12v, then ohms law gives you 1.2 amps!

Greg

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