Diode board Qs

MickDB1

MickDB1

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Hey up
After my last episode of woe with the chargeing system ( slow glowing ign light after 20 mile run ) I purchased and fitted a Voltmeter. Fired of on a 40 mile touratest watching the voltage decrease till as I arrived back home with a very warm engine with 12.4v at thrash revs. So got it to bits to find all the bits nice and clean good earths etc.So I got me flashlight and specs on to see that one of the center Diodes on the "board" dropped = broken/ unsolderedthrough possible heat. The others seem OK so I had the multimeter on Diode to test through the diodes I got a beep and .56 on readout for the 4 outside diodes 0 reading ( for the broken contact one)
and .2 for the tuther center higher diode
Questions are please

Can I re - solder this up together again

Has anyone a spare for sale B4 ebay or Motobins / works get called

Before I fit a new / newer one what should I check ???

what can have made it blow/melt Or are they as naff as reported

Thanks again for any help or offers :thumb
 
y dnt you solder it and meter it out again?before u buy?
 
MickDB1 said:
Hey up
After my last episode of woe with the chargeing system ( slow glowing ign light after 20 mile run ) I purchased and fitted a Voltmeter. Fired of on a 40 mile touratest watching the voltage decrease till as I arrived back home with a very warm engine with 12.4v at thrash revs. So got it to bits to find all the bits nice and clean good earths etc.So I got me flashlight and specs on to see that one of the center Diodes on the "board" dropped = broken/ unsolderedthrough possible heat. The others seem OK so I had the multimeter on Diode to test through the diodes I got a beep and .56 on readout for the 4 outside diodes 0 reading ( for the broken contact one)
and .2 for the tuther center higher diode
Questions are please

Can I re - solder this up together again

Has anyone a spare for sale B4 ebay or Motobins / works get called

Before I fit a new / newer one what should I check ???

what can have made it blow/melt Or are they as naff as reported

Thanks again for any help or offers :thumb
Click to expand...

The forward voltage drop of a silicon diode is approximately 0.6V. If you test them out of circuit and they read much different to this then they are faulty. Testing them in circuit can give mis-leading readings.

I am not familiar with this particular circuit so I may be able to help more if you have a circuit diagram or high-res picture.

If a diode has got hot enough to de-solder itself then there is a good chance that it is dead!
 
Local guy here repairs diode boards. He replaces the bad diodes with a press.
He cautions "Heat is #1 Killer" of the board,because the Diode's used by BM' are small as in "electrically small",restricts current.

For the money,here at least (USA),buying an "aftermarket board" makes better sense. And they are fitted with larger Diodes,less restriction. Better construction (quality),and of course better grounding.

Also,add solid board mounts for reliabilty,heat transfer and grounding.
 
Hey up again
thanks for the tips up to now. I have soldered it up again tested it out and it fails this test http://www.frankhams.freeserve.co.uk/testing_the_diode_board.htm

I have read the post regarding the Thunderchild all singin dancing diode board = looks the dogs dandleeeees

anyone had one ????
would you recomend this instead of the Motobins/works/BMW alternatives ???

I just dont want to get a newun this or other make to foooook it up bolting it on to a dodgy circuit. Is there a reason for it to fail/ get this meltdown.
Can the altenator blow thw board up ??
Shits my business - I was a plumber - all this electricery has had me confused - but I am getting the hang of its function, with your lads help and the web pages I have read
should be an expert in around 10 year

You can just see the center diode dangling down ( looks like a plunger )
 

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Spare board

Hi MikeDB1, I've had a beefy alternator fitted to my 80GS, which came with a new diode board. The old one (working when it came out, stock part, swapped out by the BoxerMan so I didn't hamfist the alternator job) has been shelved since last January in the garage if you want it.
 
I would love it !!
I am after one so I can fit it to the bike - see if blows then wonder if its something before the board thats causeing the problem - or if its OK get a new one and save yours for the travelling spare
If you send me yer telephone or email address I will send you my address to post it too
Thanks
mick :thumb
 
I'll dig it out of the garage

and see what state it's in - pic if I remember.
I'd offer to bike it up (I remember some nice roads aroud Chesterfield...) but my bike's without MoT so I get my studying done and finished first :)
Not a subscriber yet, so can't PM you.

Just a thought on the fitting/removing process - you *do* completely disconnect your battery before playing, don't you? (remember seeing something on Snowbum's site about the engine case shorting out part of the diode board and frying it when you take it out otherwise...) - I know, newbie idea, but it's not something I'd think was necessary.

edit: the uprated alternator from Motorworks came with a spangly new diode board which seems to be up to the task (400W kit for airheads if you look at their site) though I didn't have much problem with the old charging system either (girlfriend likes the back seat, was looking at 'leccy heated kit for her, didn't want to run out of juice plumbing it in)
 
Thanks for the offer but I have sorted my problem with the help from a nice man from Cork who posted me his old one which I removed a good diode from his slightly damaged board and fitted as a replacement for my dodgy one
Thanks to both of you in fact :thumb:thumb
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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