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bigmik

Guru

Joined: 20/06/2011
Location: Australia
Posts: 2914

Posted: 07:19pm 14 Oct 2012

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Hi All,

Just thought I would share an experience I had with my UBW32.

From the day I got it it was always a bit clunky on power-up.. sometimes it would be powered for about 5 seconds before I got life out of it then you would hear Bong Bing and windows would detect it. Same if I set an AUTORUN.BAS to flash an LED. Not a big deal but as development of my UBW32-MCC PCB progressed I noticed that it was becoming a bit erratic... once operational it never failed but resets and power ups were very hit and miss..

I checked the Schematic and saw that there was a 10uF capacitor (C5) connected to VCap and remembering that the original MM needed a capacitor change I piggy backed another 10uF (scavenged from an early DM prototype) on top of C5 and bingo.... No more problems

Power Up and Reset 100% of the time.

Something to store in your memory banks

Regards,

Mick

Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<<

jman

Guru

Joined: 12/06/2011
Location: New Zealand
Posts: 711

Posted: 10:04am 09 Nov 2012

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Hi Mick

Thanks for the tip.
I have 2 UBW32's and one of them would not boot with either bootloader.
I replaced the 10�f with a ceramic one (as used on the Colour Maximite)and the problem is solved.

Regards

John

aargee
Senior Member

Joined: 21/08/2008
Location: Australia
Posts: 255

Posted: 10:57pm 09 Nov 2012

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My UBW32 has just gone through a patch of lockups and/or no boots. The original designer had specified a SOT23 version of the LM317 regulator for both the +5V regulation and the 5V-3.3V regulator. For the 5-3.3V the regulator is outside its Vin-Vout tolerances, so I swapped it for a low dropout LM1117 and that solved the problem. I also removed the onboard fuse and replaced it with a link.

- Rob.

For crying out loud, all I wanted to do was flash this blasted LED.

bigmik

Guru

Joined: 20/06/2011
Location: Australia
Posts: 2914

Posted: 12:09pm 10 Nov 2012

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jman said
Thanks for the tip.

I replaced the 10�f with a ceramic one and the problem is solved.

Great to hear John,

I was a bit surprised as a Google search found not many people having trouble with the UBW32 not starting.

Regards,

Mick

Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<<

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