difference. )-:
They also own DEWALT, I guess B&D is low endof market Dewalt the pricier one ===========================================
-- Bobby G.
I have not tried that yet. Got sidetracked by an ant invasion and an X-10 "jamming" problem that de-automated half my house (the RF controlled part) for the last 5 days. As you might imagine, getting to the bare wires is not terribly simple because they're (thankfully) well-sealed against moisture (as well as servicing!).
I did try this as the relay measured only 5.5 volts powering the coil. That's when it started to rain so I had to put it back in the shed. Without knowing anything about the controller card (so far no joy in finding a schematic) and without even being able to see the component side without cracking it open, I can't determine whether it should have more voltage than that. IIRC, the lettering on the relay faced in. Tomorrow's the new day set aside for lawn mower surgery and I'll be trying to document the controller board as best I can, even if it means cutting it free from the well-attached cables and cracking the cover. It could be worse - they could have potted the whole thing.
IIRC, this has a black metal case and is about 1" by 2" by 3/4" tall. My guess is a relay failure and it looks like it will be a bitch to desolder it or even remove the casing. I haven't played with it since the original post hoping that it was simply wet in the wrong spot and would dry out. What I call the "minimum effort" fix.
That's an interesting thought. None of the people who've used it can remember whether the blade stopped instantly or not. Sounds like it would be a good safety feature but hard on the parts. Would it short out the motor or use the relay to briefly apply reverse polarity to the motor? This relay looked like it had too many pins to be a simple On/Off control, but then again, the might have already had thousands of that model around. Hard to tell without cobbling together a schematic.
Not so curious if it's spitting an arc like that!
Visual inspection by my bud who grew up rebuilding motors in his dad's shop said the motor looked remarkably unused (which it is for a 16 year old mower). Spins freely and from what he could see of the brushes, they looked fine. But he didn't have his reading glasses and he could have been looking at a beached whale. (-: The motor does spin very freely along with the blade. Tomorrow we'll try to isolate the source of the noise, which IMHO
*has* to be the relay. What else could buzz like that? If the contacts were welded together, wouldn't the device be in an "always on" state? All I get is the buzz and an occasional movement of a few degrees of the armature.Thanks for your input, Bob!
-- Bobby G.
"Robert Green"
Thanks to all who contributed to the thread. Here's how it wound up. B&D had virtually no parts for the mower or schematics for it so I decided fix it myself or scrap it. Nothing to lose. The grass was getting so high I went back to my old lawn guy because he did a much better job then my neighbor's kid, whose heart just wasn't into it.
I decided to localize the buzzing sound with my stethoscope. I hooked up the original B&D battery that, according to the charge light AND a voltmeter was fully charged, and rigged a bypass for the deadman switch (a trashbag twist tie defeats it nicely!). When I turned it on, searching for the part that was buzzing, it turned out conclusively to be the relay.
During the test, however, the whining noise from the relay dropping in pitch. I took that to mean the battery voltage was dropping. The voltmeter kept dipping downward when I connected it to the battery terminals. Not by much, but definitely a downward trend.
I took out my test headlight from my '71 LTD that had a burned out low-beam filament and hooked the hi-beam filament up to the mower battery. It glowed brightly for a moment, and then quickly dimmed down to a dull red glow. I did the same test with the supposedly good wheelchair battery which had recently come out of a working chair. It, too had tested above 13VDC when fully charged with a standalone SLA charger. And it too glowed for a second and faded to red.
The B&F original battery was a 24AH 12VDC unit. The wheelchair battery I tried as a test had 34AH 12VDC. But neither appeared able to supply the current needed to spin the blade. So I whipped out a battery from my spare wheelchair that's 55AH and was working well the day before and, well, you know the rest. Mower hummed away like it was new.
What lead me to not suspect the battery was that it worked fine for the last two outings, both within two weeks and then it failed catastrophically in heavy, wet grass. Just stopped. The unit would squeak and the rotor would spin a degree or two every few starts, but otherwise dead. From what we could see of the controller board, there's a voltage regulator with a hefty heat sink. I believe that's why the unit just stopped cold. I wasn't seeing a gradual slowdown of the motor as you might expect with a deteriorating battery. The overload, the dead drop off, the moisture and a good voltage reading all pointed in the wrong direction, at least for me. Kudos to those of you who stuck with the simplest explanation: "It's the damn battery!" (-"
I've put the mower back in storage. No sense in buying a spare until I'll be doing the yard work again since they do die over time, used or not. This was a good lesson in not over-thinking the problem. Now my friend that I give gas to for hooking up a hard drive's Molex power connector the wrong way and frying its circuit board can rib me about insisting this was something other than a simple, garden variety dead battery.
Sheesh.
-- Bobby G.
"I have yet to see any problem, however complicated, which, when looked at in the right way did not become still more complicated." Poul Anderson
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Sorry to Join this game so late, but I have a B&D cmm625 (working nicely wi= th a 5 year old battery I just desulfated) and a CMM630 that I am fixing fo= r a friend. =20
The CMM630 was shutting down after 5 min or so in tall grass (not even wet!= ) and we suspected a battery (only 1 year old, 35 AH). However, when it lo= oks to be something along the lines of your struggle (above). We found the= battery to be good (better than mine, when moved to my unit) and not dropp= ing badly in voltage either during operation or immediately after the mower= abruptly stops. We then suspected the motor or the control unit (there's = not much else!)
It's not easy to swap motors/control units on these mowers, so I carefully = swapped out the control unit and the brushes (crimped at to the controller)= . In this way I was able to test that the motor ex brushes was fine with m= y good mower's controller. =20
Both motors with the known good controller were drawing about 20 Amps. Bru= shes on each looked identical as did the rest of the parts of the . The 'b= ad mower' was drawing 33 amps on start up from its controller, though. Wh= ile we had both mowers open we lubed the top bearing (a felt hole at the to= p) and the bottom bearing (after SAFELY removing the blade etc from the bot= tom of the mower) with 3 or so drops of good oil (we used Mobil-1). After = reassembly the 'bad mower' was down to about 26 amps, so not sure if we've = helped much. The 'good mower' battery is only 26AH, so it's possible that = the electronics don't like a battery with the ability to put out more curre= nt, or simply that they are a bit fried. We hope that lubrication buys us = a little more headroom before the silly thing shuts down due to 'overload'.
If anyone has the schematics please direct us to them! (we have 2 'version =
5' controller boards...and I have a version 3 I got from a junked unit).By the way, we run our mowers off 100% solar (easy to do with one smallish = solar panel...see my site:
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