On Thu, 11 Mar 1999, Larry Macy wrote:
> This is for those electrical gurus.
>
> On Tues night as I was traveling to the MG Club Meeting (Where I was
> named on of the MG Enthusiasts of 1998 and to the "Board of Directors"
> and 50¢ will get a cup of coffee) I noticed that the headlamps were
> acting kinda weird. They were fine for a while and would gradually start
> to dim, then suddenly go back to full again. This pattern repeated itself
> constantly about every 20 sec or so.
>
> The next night I noticed that the Alt warning light was following the
> reverse pattern (It hadn't been the pervious night) Bright when the
> lights were dim and off when the lights were bright.
> All of the above at a constant 60 mph. At Idle the Alt light was off and
> the lamps seemed normal.
> I checked the belt but it is not worn nor too loose.
> I suspect I need a new Alt. Please give me another option. My Midget has
> become my only form of transportation and I need to get this fixed quick.
I'm afraid I agree.
It's possible that the failure is in the diode rectifier pack, but since
that is inside the alternator, the easiest thing to do (especially if you
don't have other alternaters with, say, bearing failure instead of
electrical failure lying around) is to replace the alternator.
When my B alternator went out, it was a bad solder joint on *one* of the
diodes in the rectifier pack... so I was getting only some of the
rectified waveform (hence, less charging). We had access to a pile of dead
alternators and were about to find a diode pack which was good, and
swapped the good parts all into one unit.
The regular interval is puzzling, though. Oh, does this happen with the
headlights *off*?
--
John M. Trindle | johnt@tsquare.com | Tidewater Sports Car Club
'73 MGB DSP | '69 Spitfire H Stock | '88 RX-7 C Stock
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