When I bought my sailboat Sola a year and a half ago the hour meter for the diesel engine was nonfunctional. It is an LCD readout on the lower part of the tachometer. In the totality of the boat purchase this was not a major issue for me, but something that I’d like to get fixed to better keep track of engine maintenance.
Recently I had a major problem with my transmission, and the lack of knowledge about the condition of my engine became something I was very aware of while talking with mechanics. I spent a week sitting around in Port Townsend waiting on parts to get my boat fixed and had plenty of time to watch YouTube videos about fixing things on boats. I came across this one related to possibly fixing my hour meter with a $30 part. It explains what appears to be a common problem with Yanmar control panels, the LCD display of the hour meter fails while everything else continues working, including the counter chip in the background. Replacing the LCD panel gets a working counter without losing the underlying data. $30 is inexpensive compared to everything else I was spending to get the boat fully functional again, so I ordered the part. I paid via PayPal and was able to have PayPal specify my delivery address directly which made the purchase process very easy.
Instead of taking the entire panel out of my cockpit, I crawled into the lazarette, unplugged the cable, and removed the four screws holding the tachometer in place. Mine used Torx T10 screws.
Once the tachometer was sitting at my table, it’s held together by three torx T10 screws. After losening the screws, I was able to push on the screws, popping the lens and gasket out of the front of the housing. The lens itself is only held in place by friction.
Here you can see the internals. The upper plate holds the LCD connected by the ribbon cable, and has curved light guides coming towards incandescent lamps on the lower plate, but is primarily clear plastic with an opaque sticker gauge display on the top. The pin from the needle stepper motor protrudes through. I had to pry the needle off the pin with more force than I hoped, but it went back in place afterwards.
Replacement part in antistatic package, existing condition of the tachometer, and me slowly prying the display sticker from the front of the clear plastic.
I wish I’d ordered a replacement for the tachometer lens. It’s been scratched for the entire time I’ve owned it. Not a significant issue, but it would have improved the appearance.
I waited till I had put everything back in place before I started the engine and was quite pleased to see a display. 12,984 is more hours than I expected, but at least now I have a reference going forward.
The original LCD has the numbers LPH3930-2 05215235 printed on the edge, which is useful to recognize for future web searches. Simply based on that I was able to come across references to fixes for tachometers used on other brand engines. I also came across mention of a calibration menu, which might be useful. I noticed that there is a momentary switch button on the back of the unit. I only noticed it when I pressed it by mistake. Searching for “Siemens VDO Tachometer Installation and Operation Instructions for Programmable Tachometer with Hourmeter N 02 012 195” helped me find details on the calibration button itself.