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MM_Wombat
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Joined: 12/12/2011
Location: Australia
Posts: 139

Posted: 07:33am 06 Jan 2012

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1> My Maximite is getting really hot, and I was wondering if I could use a computer psu to power my maximite(Overkill). Could I use the 7V option ( +12 and +5 )?

2> I have two transformers

Both say 9 V, One at 300mA, and the other 1.2A

When I measure with my multimeter they read 13.1V and 14.8 V Respectively

Is there something wrong with my transformers?

3> I built an Altronics kit #3220. Versatile low voltage adapter. Which has an outputs of 3,5,6,9,12,15 V Should I just use another one of those to supply 9V? ( and it measures 9V when I set it to 9V)....Probably the best way to go, only 7 AUD.

Cheers
MM_WombatEdited by MM_Wombat 2012-01-07

Keep plugging away, it is fun learning
But can be expensive (if you keep blowing things up).

Maximite, ColourMaximite, MM+

Gizmo

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Joined: 05/06/2004
Location: Australia
Posts: 5078

Posted: 08:03am 06 Jan 2012

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Hi Wombat

Yes its pretty common for the older or cheaper power adapters to measure higher than the label. Under their rated load, they would be close to their rated voltage, but for something that uses little power like the Maximite, the voltage is just too high.

The Maximites 5v regulator needs to dissipate the extra voltage as heat, and anything over 10 volts is just too much.

If the #3220 regualtor is providing a true 9v, then it will fix your overheating problem. Or you may find a old 6v adapter that measures at like 7 to 10 volts, it would be OK too.

Glenn

The best time to plant a tree was twenty years ago, the second best time is right now.
JAQ

Olimex
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Joined: 02/10/2011
Location: Bulgaria
Posts: 226

Posted: 08:41am 06 Jan 2012

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one of these cheap iPhone chargers with USB mini cable will be fine for any DM

http://www.ebay.com/itm/USB-Adapter-Wall-Charger-iPhone-3G-4 G-iPod-Touch-nano-US-Plug-5V-1A-Yellow-/220862262593?pt=Othe r_MP3_Player_Accessories&hash=item336c6aad41#ht_3319wt_954

BobD

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Joined: 07/12/2011
Location: Australia
Posts: 935

Posted: 09:37am 06 Jan 2012

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Hi Wombat
Altronics have a plug pack power supply that they suggest for the Maximite. It is 9 volts 0.67 amps regulated. The regulated means the voltage stays pretty much at around 9 volts all the time so less chance of the MM over heating. It has exactly the right plug for the Maximite. The catch is it ain't cheap at $17.95. It also has a red power on LED. I have one of these. It fits into a standard space on a power point or board. It's no wider than the plug on a cord. Part number is P9237B.
Bob

BobD

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Joined: 07/12/2011
Location: Australia
Posts: 935

Posted: 09:50am 06 Jan 2012

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Just found your power kit on Altronics and that will easily do the job http://www.altronics.com.au/index.asp?area=item&id=K3220 and a lot cheaper.

edit
Maybe not better. Do you still have to connect it to 240volt mains? or have you got something else in mind?Edited by BobD 2012-01-07

MM_Wombat
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Joined: 12/12/2011
Location: Australia
Posts: 139

Posted: 01:42pm 06 Jan 2012

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I would just keep using the powerpack with the lowest voltage to power the Kit #3220. It was one of those kits that powers the 74HC595 shift register project I am working on.

Cheers
MM_Wombat

Keep plugging away, it is fun learning
But can be expensive (if you keep blowing things up).

Maximite, ColourMaximite, MM+

MM_Wombat
Senior Member

Joined: 12/12/2011
Location: Australia
Posts: 139

Posted: 03:04pm 06 Jan 2012

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I am running that 9 V 1.2 Amp power pack, through the voltage regulator..

I set the voltage regulator to 12 V
with 300 Ma current the voltage from the powerpack dropped to 10.8, and the output power is 9V( Load 14 leds, in led string, resistors inbuilt)

Unit has been running for half an hour, and the chip is not even hot...

At the same time I was doing this, I was using my MM, getting rid of line numbers in maxifont, and the MM got really hot...(used the other powerpack rated 9v 300 mA but outputting 13.1 V at little load. MM uses 150 mA when not doing much, I think...

Guess I know which way to go

Keep plugging away, it is fun learning
But can be expensive (if you keep blowing things up).

Maximite, ColourMaximite, MM+

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