'89 Coupe, alternator/reg experience

[dshepp806]

Greetings to all!

Just wanted to share a recent experience with the group.

I've an '89 Coupe with a Passport Radar Detector, windshield mounted, programmed to render the CD voltage measured at the cig. lighter socket. I've previously used a voltmeter mounted to the cig lighter/measurements with BOTH devices are quite comparable, if not exact. ...In any case::::::::::::::


She (the Passport) usually shows me around 14.2 - 14.4 VDC while driving,...a "circuit unloaded" measurement, BTW (no AC , lights, etc.) Occasionally, I would notice that the display would be around 14.6 - 14.9 VDC. Planned to have the battery load checked for the HE## of it.

..BOOM! Two days before vacation departure, the Passport hits limit and renders it's audible,..railing at 16.5 VDC. (Passport's limit,...who knows WHERE it really went?) It would rail downward to lower 14'sh VDC then rail; upward to PP limits at 16.5 VDC. I quickly swapped the cig monitor with my digital MM, verifying what I saw on the P/Port meter. She showed me 16.9 VDC before reverting back to a normal reading....I then swapped the PassPort back in postion,...convinced this was a REAL event.......she stayed steady after ALL of that....every moment normal............Geeeeze,..How did the DME react to this event? I now need to investigate the onboard regulation capability of the DME for these type of B+ buss events.....(another discussion...)

[[[[[Belt tension,..not an issue.]]]]]]]]]]]]

I immediately order a new regulator from our sponsor, overnight delivery,..in a panic,..as I NEED to take the P-car to Apalachicola,..it IS the essence of my vacation experience,...the common denominator, 4sure. Ultimately, my work schedule did not permit my rendezvous with the repair,..opting to turn this over to my P-wrench, for a new (rebuild) alternator, to include new reg/diode bridge.....He calls me later to tell me that the alternator/assembly was the ORIGINAL unit! This speaks to longevity, eh? GEEEEZE: 17 plus years of age
on the brushes, diodes and regulator...........(I bought her in 11/2006)

.....inanycase,..she's FRESH now....locking in 14.2 - 14.3 VDC on the 4 day vacation trip........

....to all: figure a way to monitor that voltage. I'm looking to get the proper DC instrumentation in place via meters....The difference between battery terminal points vs. the cig/lighter is only a 1/10 drop (good copper!), so I'm comfortable reading (and reacting) to this measurement point. I'm sure there are many options for instrument installs...this board has some great reads, ahead, as to options.......

In any case,..just wanted to share this "event".....and a no nonsense approach (timetable) to remedy....

Looking forward, my intution is to look for the "tolerances: of the DME circuitry to overvoltage levels,..their regulation capabilities, as well as overvoltage shunt capabilties. I know NOTHING of the circuits and will require MUCH investigation of this, first order. Having worked with mucho electronic circuits, I look forward to this info seeking..I'm sure Loren can expound....

.I'm up for prints on the DME....will tell the tale:

....................(probably another thread)

back to point: MONITOR THAT VOLTAGE:::::::::::::::LUCKILY MY PASSPORT DOES THE TRICK""""""""::::::::::::WITH AUDIO!!!!!!!!!!!!!!!!!!!!!!

Best,