Abby’s Guide > Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) > Discussions > Cheap Tachometer Hour Meter 2-4 Stroke Small Engine Spark Purchase from eBay
Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions |
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trouts2
Location: Marlboro MA
Joined: Dec 8, 2007
Points: 1328
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Re: Cheap Tachometer Hour Meter 2-4 Stroke Small Engine Spark Purchase from eBay
Reply #21 Mar 6, 2011 12:10 pm |
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Just for reference; It looks like all NM_Runner and Rlics boards are similar to mine, all HM011's but all different revisions. Mine's from 5/10/2010. Relics is stamped 2010, has different parts and seems newer. Mine has GND at the open pad by the wire input lead so I added a ground there and drilled an outlet hole for the ground wire. It's now operating well on 2 and much more stable. ( I have three of these). They were not so stable before and would take a lot of time settling. Often they read better in 3 than 2. I had tried a few different wire leads, shielded and non shielded. The length and type of wire would cause readings changes. They had to be frigged and fragged with to get good readings. Often they would read well in a small range rather then read well over the whole range of 700 to 3600 rpm. They are noisy. If I put an unconnected meter close to a connected meter the unconnected meter will display rpm readings. The upshot is there are a number of rev's of this board out there with various features. The single wire will work but has to be messed with to get reliable and consistant readings. The grounded version of the HM011 is the one to get.
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trouts2
Location: Marlboro MA
Joined: Dec 8, 2007
Points: 1328
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Re: Cheap Tachometer Hour Meter 2-4 Stroke Small Engine Spark Purchase from eBay
Reply #23 Mar 6, 2011 2:19 pm |
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It will probably reset by itself with a bat install. There "reset" printed on the board so worse case those pads could be messed with. It would be nice to have a schematic. The two big chips are a 7400 series which is a simple D flip flop and probably takes the S1 and S2 inputs. The other is an 8 bit risc chip. The data sheet for it is online. It should have a reset pin which usually is pulled to ground for a reset. The back cover comes off easily and the soldering is simple with a pencil tip soldering iron. I put a short wire on for ground and will put a perminant wire on machines so the meter can be removed easily. The case is not brittle so easy to drill without cracking or breaking the case. The back cover also popped off easily with a knife. Mine was advertised as "replaceable battery" and also listed as potted. It's not potted and there's no batter holder or compartment as I expected. There's probably a lot of ticked off people who bought the single lead version. On a closer look your board and my board are very different.
This message was modified Mar 6, 2011 by trouts2
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