Two problems for the price of one

[Jerry Hammernik]

Is it just me or does it seem like every time you fix something, two others break. I just put new chips in my Micrologic GPS and now it works, but:

I've picked up a nasty noise when transmitting on the VHF with the engine on. I've had the alternator in to the shop and they say it is as quiet as a mouse. They suspect the radio. When the engine is off the radio is fine. I was sure it was the alternator but they swear that's not the culprit. Any ideas, fixes, methods of checking would be gratefully received.

Problem 2, the tachometer worked just fine a week ago, now it doesn't read at all. The problem occure before I took off the alternator so I didn't mess anything up there. Any secrets to waking up a sleeping tachometer. I look forward to the collective wisdom.

Jerry Hammernik
Lion's Paw CD 28 #341



dauntles@execpc.com

[Mark Yashinsky]

I believe you have a two or three cylinder diesel in Lion's Paw and , as I remember, in most cases, the alternator is used as the sensor to send engine speed to the tach. Trace the tach wire back to the engine and confirm this. If yes, everything seems to point to an alternator related problem. Did the shop test the alternator under load??? might have some bad diodes that would produce sufficent voltage, w/o a load or light load, and might be "quiet", but when the alternator is asked to perform will fail to output and give a lot of noise. Also check all alternator/battery/suppression connections. Along w/ capacitors, the batteries are used to suppress the noise from the alternator. Did anything happen right before this started (switching battery banks while running the engine)???

[Ken Cave]

If you have the Volvo MD7A in your 28, you will find that the tack on the engine is just behind the alternator on the block itself. There are two wires that go to it, and they do fall off sometimes due to vibration of the engine-and when working on it (like pullling off the cleaning the air filter which I did!)

Just be sure to put the wires back in the right order-and you should not have a problem.

Ken Cave



bcave@whidbey.net

[Kurt B. Kaiser]

Try taking the alternator belt off, start the engine, and see if the problem is gone. If the belt also drives the water pump, be sure to run only a few seconds, but that should be long enough to decide.




kbk@deletethis@shore.net

[Joe Wysong]

If you have the Volvo MD7A in your 28, you will find that the tack on the engine is just behind the alternator on the block itself. There are two wires that go to it, and they do fall off sometimes due to vibration of the engine-and when working on it (like pullling off the cleaning the air filter which I did!)

Just be sure to put the wires back in the right order-and you should not have a problem.

Ken Cave

Some CDs only have one wire leading from the alternator to the tach so don't go nuts if you only find one white wire. Otherwise, Ken is quite correct.

When electricity has no place to go, it often radiates into the either. If your tach wire(s) are disconnected, this could be the cause of the VHF interference. I suggest you get the tach working and then address the radio interference.

Joe



tgjournal@gestalt.org