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Forum Index : Microcontroller and PC projects : MM: intermittent power fixed
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James_From_Canb Senior Member  Joined: 19/06/2011 Location: AustraliaPosts: 265 |
This is just a 'heads-up' in case others have a similar problem. While I was trying to figure out a problem with the Maximite and a 13 port USB hub I decided to also find out why the power from my 9V DC power pack (aka wall wart) intermittently failed. I originally used USB for power, but changed to a power pack because I wanted to use the front on/off switch. I have a box of power packs left over from discarded appliances, so I found one that had the correct voltage and polarity, and a plug that fitted the Maximite. However, the power to the Maximite would occasionally fail if the power cable was moved. The answer is that the power pack I used only had a 2.1mm connector. The Altronics Maximite (and probably all the rest) uses a 2.5mm connector. I ordered a regulated transformer and 2.5mm adapter from Altronics and the power now works faultlessly. I see that practically all 9V DC power packs come with 2.1mm connectors, so others may have made the same mistake. I'll email Geoff and ask him to include the 2.5mm requirement in the Maximite Hardware Manual. Now to get the USB problem sorted.... James My mind is aglow with whirling, transient nodes of thought careening through a cosmic vapor of invention. Hedley Lamarr, Blazing Saddles (1974) |
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BobD Guru  Joined: 07/12/2011 Location: AustraliaPosts: 935 |
James Unfortunately you have the story a little backward. The Altronics Maximite actually does have a 2.1 mm Inside Diameter plug. For the record, the Outside Diameter is 5.5 mm. I just measured the plug, inside and out. The Altronics parts list also states it is 2.1mm. Where your story has a problem is that a 2.1 mm Inside Diameter plug would not fit on a 2.5mm pin in the socket. So you must have had a 2.5mm plug pack mating to a 2.1 mm socket which, as you found out, is not reliable. Quote from Altronics parts list: DC power socket 2.1mm PCB mount ......... CON1
Yes, when you do get the right plug for the socket it works very well indeed. When buying an MM from Altronics they do suggest the correct plug pack which is their part number M9237A . It is a small unit which fits comfortably on a power board with other plugs in adjacent sockets and it has a red led indicator for power on. |
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| James_From_Canb Senior Member Joined: 19/06/2011 Location: AustraliaPosts: 265 |
Thanks Bob. I asked the Altronics sales person what the correct size was, and he said 2.5mm. Also, this link says 2.5mm. No wonder I get confused 
He sold me a 92377B power pack which is the same except for the different body shape. Anyway, my 2.5mm plug sits solidly in the socket and I don't get power cutouts anymore. My only complaint is that the 2.5mm adapter plug disconnects easily from the end of the power cable and I have to get my multimeter out every time to make sure I get the pins the right way around. A dab of superglue should fix that problem though. You've got me intrigued. I'll have to find my original Maximite kit documentation. Maybe different kit batches used different sized plugs. 2.1mm makes much more sense because the 2.1mm power packs are so common - and you don't need an adapter which can slip off. James My mind is aglow with whirling, transient nodes of thought careening through a cosmic vapor of invention. Hedley Lamarr, Blazing Saddles (1974) |
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| BobD Guru Joined: 07/12/2011 Location: AustraliaPosts: 935 |
Altronics are being inconsistent. The catalog page link certainly shows 2.5mm but the second link you quoted which was also the one I linked, clearly shows 2.1mm. Someone is going to be seriously misled with this and they will spend money on the wrong product. The best part is you have solved your problem. I used shrink tubing to keep the adapter on my cable. Bunnings is a good source (cheaper than Jaycar) of larger shrink tube. The other trick you can do is get a whiteout pen from the newsagent and mark both pieces so that you know the correct orientation. |
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| James_From_Canb Senior Member Joined: 19/06/2011 Location: AustraliaPosts: 265 |
Bob, You're right. I've checked the paperwork that came with the kit, and it says 2.1mm. I guess the lesson is that if people have intermittent power connections when the power cable is moved, it might be the wrong sized connection. It could also be bad soldering, of course. If they have the Altronics power pack (or similar) that takes different adapters, they could buy a 2.5mm one (mine was $0.90) and see if it makes a difference. Thank for the tip about the whiteout pen. The shrink tubing sounds even better. James My mind is aglow with whirling, transient nodes of thought careening through a cosmic vapor of invention. Hedley Lamarr, Blazing Saddles (1974) |
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| paceman Guru Joined: 07/10/2011 Location: AustraliaPosts: 1329 |
Hi James/Bob, I've run into this problem before with another kit (pre-amp): I'd hate to think so but I seriously wonder whether the confusion is deliberate - from both Altronics and Jaycar. It could do wonders for extra plug-pack sales! The length of the plug is also an issue because there are both short and long versions. I had a short one  left over from something else as well (old router I think) and couldn't figure why things didn't work. It turned out the short plug was not long enough to activate the switch built into the socket!
There are a myriad combinations of diameters of the socket/plug/case/pin all doubled again by short/long and doubled again by switched/un-switched sockets. To hopefully get around this issue in future I invested in some spare plug connectors to solder to plug-packs and, best of all, two converters (2.5 plug to 2.1 socket & the reverse). Futurlec have a big range of these and they're pretty cheap. I haven't noticed the local suppliers carrying these converters. Greg |
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djuqa Guru Joined: 23/11/2011 Location: AustraliaPosts: 447 |
This is another reason I NEVER EVER buy anything from Jaycar / ALtronics anymore They are going the way of DSE(and look how they have ended up becoming) TOYS/GADGETS/CRAP rather than electronic components and related products. Other reasons I never use them. 1/ Lack of Paypal payment option. 2/ Lack of Technical Knowledge. 3/ Lack of Product choice. 4/ PRICING (Consistently too expensive) BTW I modded my MM (Original and Maximite SM1) units to use Powerpole connectors. I personally hate the whole hassle of using DC coaxial sockets. VK4MU MicroController Units |
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| paceman Guru Joined: 07/10/2011 Location: AustraliaPosts: 1329 |
Hi djuqa, What is a "powerpole" connector? Greg |
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| djuqa Guru Joined: 23/11/2011 Location: AustraliaPosts: 447 |
http://andersonpower.com.au/store/index.php?main_page=index& cPath=8_29 Clever connectors VK4MU MicroController Units |
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| paceman Guru Joined: 07/10/2011 Location: AustraliaPosts: 1329 |
Thanks for that - unfortunately the site doesn't have any pictures so none the wiser. Do you have another link with a photo? Greg |
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| djuqa Guru Joined: 23/11/2011 Location: AustraliaPosts: 447 |
http://microcontroller.net.au/images/stories/powerpoles.jpg VK4MU MicroController Units |
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| paceman Guru Joined: 07/10/2011 Location: AustraliaPosts: 1329 |
Looks good and solid. I'm surprised they fit on the MM board though - they look big-ish compared to the barrels. No dimensions given on Andersons site though which is a bit remiss of them. Thanks, Greg |
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