[C320-list] Instruments gone awry

[John Frost]

I have found in cars and boats and other electronics, that if multiple instruments are acting flakey, the culprit is often a bad ground. A weak ground forces the instruments to send their return current through other instruments causing multiple, seemingly unrelated flukes. Good luck!

Thanks,
John

John C. Frost
President
Safety Technology Services, Inc.
2627 Trailway Rd.
Huntsville, AL 35801
(256) 650-0335


-----Original Message-----
From: C320-list [mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of Brad
Sent: Thursday, June 13, 2019 11:39 AM
To: C320-List at Catalina320.com
Subject: Re: [C320-list] Instruments gone awry

I have a newer setup (St60s) but was having similar issues.  I opened the instrument box (mine are clustered next to each other at the helm) and cleaned each and every contact with contact cleaner.  My issues cleared up after doing so.  Your results may vary.    My wind is still wonky, but I feel it’s more about adjustment than functionality. 

Sent from Mail for Windows 10

From: William Russell
Sent: Thursday, June 13, 2019 12:22 PM
To: c320-list at lists.catalina320.com
Subject: [C320-list] Instruments gone awry

On my 1998 C320 (#545) I have ST40 Plus instruments (speed, wind, depth, autopilot).  They've always worked fine in previous years.  This year, I'm getting very unreliable (or non-existent) performance from them.  Speed seems to work, but I've not checked it against a GPS to see how accurate it is.  Wind direction doesn't work at all, until partly through a race it starts to read, though not consistently or accurately compared to the Windex.  Wind speed reads, but again, I can't tell how accurately, and it often seems way off. Depth is completely inaccurate - sitting at the dock in 6-7 feet of water, it showed 14-16 feet, and changed minute by minute even though we weren't moving.  The compass on the autopilot reads 20-30 degrees differently than the binnacle compass, and the "wind" setting on the autopilot won't work without an accurate apparent wind direction.
I can't figure why I would get such variable and unreliable performance from all of the instruments at once.  They were installed by the (very
knowledgeable) previous owner, so I don't really know where to start to troubleshoot.
Any suggestions?
Bill Russell
"Little Wing," 1998 C320, #545
Cayuga Lake
Ithaca, NY