Does CD28 Have Engine Alarm Buzzer?

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John Ring
Posts: 519
Joined: Feb 5th, '05, 14:38
Location: CD36 #135 Tiara, MMSI:338141386

Does CD28 Have Engine Alarm Buzzer?

Post by John Ring »

I'm thinking I should hear a buzzer when I turn the key to start the motor, but I don't. The wire diagram in the MD7A manual shows a buzzer, but it also shows a panel that is different from mine. I looked around in the locker, but couldn't find anything that looked like a buzzer.

The amp and oil pressure lights work, but no sound. Is it possible my 1979 CD28 didn't come with a buzzer? Or, is it hidden away somewhere and in need of repair/replacement?

Thanks in advance,

John Ring
CD28 #241 Tantalus
www.yachttantalus.com
Rperlot
Posts: 53
Joined: Jun 1st, '05, 23:03
Location: CD28Megan Ann #352,Bainbridge Island, WA

I gots one.

Post by Rperlot »

On my '82. For what its worth.

Rperlot.
Oswego John
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Joined: Feb 5th, '05, 20:42
Location: '66 Typhoon "Grace", Hull # 42, Schooner "Ontario", CD 85D Hull #1

Engine Alarm Buzzer

Post by Oswego John »

Hi John,

You may have an inactive buzzer or none at all. Not being familiar with your particular electrical system, it's hard to say.

Some boats have original equipment buzzers, some don't. Of those that didn't have original equipment buzzer, many owners installed add-on buzzers as well as pilot lights for other systems. During the years, I have wired up more than a few, especially bilge pump warnings.

You might be able to simplify the search for a buzzer by doing the following.

Let's talk about the oil pressure. You said that the oil warning light is operable. In many instances, a hot (12V +) wire is attached to one side of the lamp. Another wire runs from the load side of the lamp to an oil pressure sender unit. This sender unit is a single pole switch which has the wire from the warning light attached to it's line side and it's load side is system grounded. Oil pressure, or lack of it, actuates the switch.
Sufficient oil pressure opens the switch and there is no current flow in the warning light circuit. The key to the starter also supplys power to the warning light. When the key is ON and the engine isn't running, there is no oil pressure and the sender switch closes, providing a ground to illuminate the warning light. (and possible buzzer)

Check the inside of the panel with the pilot or oil warning lamp wiring. Look to see if there are more than two wires to the lamp, one hot feed, one to the sender unit. This will be a straight series hookup. If you find more than one wire on each side of the lamp. trace them to where they go. That's where you might find the buzzer. The buzzer will probably be wired in parallel to the pilot light

Should you or any other reader decide to add on a warning buzzer, I have had good luck installing a piezo tweeter rather than a buzzer. The tweeter commands more attention over the engine noise than the buzzer.

I hope that this helps somebody.
O J
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Stan W.
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Joined: Feb 5th, '05, 20:33
Location: Montgomery 17, Duxbury, MA

I have the buzzer but it was never installed

Post by Stan W. »

Hi Jon.

The base-level panel did not have a coolant temperature guage so the buzzer did double-duty, warning of low oil pressure or high coolant temperature. Our boats have an optional deluxe intrument panel which has a coolant temperature guage and no place to put a buzzer. A buzzer for low oil pressure still would be useful and I imagine it would be easy to retrofit if you wanted to.

My boat actually came with what looks like an unused buzzer from the base-level panel in a box with lots of other loose parts (my favorite is the little brass plaque that says "don't disconnect the battery when the motor is running" ... in Swedish). It appears to me that Volvo did supply a buzzer with the deluxe panel but Cape Dory chose not to use it. Off course I've never gotten around to wiring it up myself and still rely on frequent glances at the panel instead.

Rperlot, where is your buzzer located? Did someone drill an extra hole in the cockpit well?
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Stan W.
Posts: 487
Joined: Feb 5th, '05, 20:33
Location: Montgomery 17, Duxbury, MA

May have found wiring diagram for our panel

Post by Stan W. »

The on-line manual on the CDSOA website appears to have a wiring diagram for our panel at page 31, figure 83. The manual says it is for late production MD6As but I think it is the same panel that we have. It does not show any buzzer.

http://www.capedory.org/manuals/Worksho ... A_MD7A.pdf
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John Ring
Posts: 519
Joined: Feb 5th, '05, 14:38
Location: CD36 #135 Tiara, MMSI:338141386

I Think You're Right!

Post by John Ring »

Stan,

I looked over the diagrams labeled "MD6A" and "MD7A" on pages 31 and 32 of the Volvo manual, and I think you are right.

The engine side of the MD7A diagram on page 32 looks right, but that panel shown is nothing like mine. However, the wiring diagram on page 31, labeled "MD6A" looks correct for the panel attached to my MD7A.

Thanks for spotting that!

Per O.J., if I understand correctly, a piezo tweeter would be wired in parallel with the engine temp and amp lamps. I like that idea, and will add a tweeter.

Thanks Again,
John Ring
CD28 Tantalus
www.yachttantalus.com
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