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Circuitbenders Forum => BENDING TIPS => Circuitbending discussion => Repair advice & questions. => Topic started by: amstrad664 on November 30, 2009, 04:13:11 PM

Title: speak&math dead - need help
Post by: amstrad664 on November 30, 2009, 04:13:11 PM
hello

i think my speak and maths is dead, i hope not, maybe someone here can help me.
it died when u tried to bend it and i think the problem is on the power board : when it died, a transistor on the power board was very hot, so i change it, but it still very hot, when i powered the S&M on.
So.. i don't know what to do now to fix it!
i have tested all the resistance and all the diode and everything seems to be allright
Are the ransistor pnp or npn?
and what is this component (in red on the photo)?? it seems to be hot too when the power is on.
(http://i180.photobucket.com/albums/x39/amstrad664/SpeaknSpell_PCB.jpg)
thanx in advance for your advices

Title: Re: speak&math dead - need help
Post by: Gordonjcp on December 01, 2009, 11:31:44 AM
That's the transformer.  The power supply is a wee oscillator that steps up the input voltage to a much higher voltage to drive the VFD.
Title: Re: speak&math dead - need help
Post by: amstrad664 on December 01, 2009, 02:33:40 PM
ok, thank you.
do you know how to test this transformer? and if there's a possibility to change it?
is this a hard-to-find component?
thanx
Title: Re: speak&math dead - need help
Post by: Circuitbenders on December 01, 2009, 04:34:34 PM
I'm guessing that what you thought was a transistor is in fact some kind of voltage regulator or something. I have a vague recollection of googling part numbers from an S&M power board a while back and one of the transistors was in fact something else in a TO92 casing