Hi Guys,

Thought I’d throw this out there. I have a Crest Rx that quit on me a few weeks back and i decided to have a look at it this weekend. I know Crest has packed it in and that Navin was going to continue repairs but I was hesitant to send it away. I don’t want to start/continue a discussion about Crest in this post. Anyway, I took it to Winonna Garden Railway today and John the owner showed me the location of a couple of small fuses that could be the problem. Anyway, back on my bench this evening, I soldered a wire jumper across each fuse and “magic”!..it came back to life.

Here is the question…each of these nano fuses is marked with a “5”. Is that 5 amps? and could I just solder some small 5 amp auto fuses in their place.

Any thoughts would be appreciated.

P.S. - even if I can put new fuses in their place, I’m still worried/wondering why they popped in the first place? The loco was a LGB Forney running all by itself. It had never had any problems before - just quit on me. No overload/overheat warning either.

5 ah quick fuse ,why they blow = overheating and then usually on of the mosfets gonna blow if the rx works one way but blows the fuse the other way = mosfets happened to me both rx are in the mail to NAVIN !

The 5 amp Littlefuse is available from Mouser Electronics under part number 0437005.

Thanks for the replies Manfred and Paul. I was checking out Mouser’s site but that part number sure helps. Hope my soldering skills are up to the task.

Mike

oops,i pass on this one,thought its the revo adaptor board !

Usual failure mode of a mosfet is to short. Had a home made receiver that suddenly would not reverse. Would stop and go forward FAST!!! Low side driver on one side was shorted. Of course, I fed the pwm signal to the low side, so when the high side on the other side turned on to go forward, the loco MOVED. When the high side driver on the shorted side turned on, the battery shut down for overcurrent.

Be very careful soldering a surface mounted fuse, it is a material that heats up and melts so soldering too long can also melt this material thus giving an instant open fuse.