Re: (ET) Aaargghh!!!!

["Briggs, Michael" <Michael Briggs unh edu>]

On 25 May 2017 at 22:20, jlantonucci comcast net wrote:

>>     The charger is hard wired to the battery pack like Jim said.  
>> Turning off
>>     the power disconnect does not disconnect it
>
>David Roden wrote:
>
>Interesting.  My HSM shows the E15 charger going through the main
>disconnect.  Dunno if my own E15 is wired that way though.
>
>Also, Michael didn't get his fireworks until he engaged the disco.

Exactly what I was thinking David. I'm 99% positive the main disconnect 
disconnects the positive side of the battery from the charger (on mine). 
The tractor won't charge with that disconnect open, and if it was 
permanently connected, there's no reason closing the disconnect should 
have caused the fireworks - since it shouldn't have changed anything. 

>The symptoms described suggest at least one shorted diode in the charger,
>though since it apparently sent out smoke signals, it might be open now.

Ok, new diodes it is then. I haven't touched the charger in over 10 years 
- where exactly are those diodes? I don't suppose anyone has some pictures 
or a video showing there they are. Most of my tractor is clean and shiny 
and looks practically new - but I can't say that about the charger. It 
looks every bit of its 40+ year age. 

>Looks like you'll have to remove the heatsink, press or hammer the old
>diodes out, press in the new ones, and put it back.  Jim mentions that the
>aluminum may stretch so that the new diodes fit loosely, don't dissipate
>heat well, and fail.  He has a point.
>
>Jim conveniently offers a complete heatsink and diode assembly which is no
>doubt the easy way to go.  It is of course quite a bit more expensive.
>
>I tend to take such challenges as inspiration to my hacker side (the "make
>it work" kind, not the "wreck someone's computer" kind).  The nice thing
>about this route is that if you can find diodes locally, you're back up 
>and
>running that much sooner.

The hacker side of me also generally likes the challenge - but in this 
situation I just want to get it working again without too much time and 
frustration, since my plate is more than full (the whole reason for 
switching to a robotic mower - no time to mow, no time to fix tractor, 
etc.). So I like the quick and easy route - so I'll order the whole 
heatsink assembly. I should probably also clean up the charger while I"m 
in there - it's kind of nasty. 

Thanks everyone!

Mike