I'm trying to fix a partially working acumos AVGA2 VGA that one of the transistors was removed.
Someone would have equal VGA could tell me which used transistors ?
Which one you are missing?
The D1 which is a diode, or Q1, which might be a transistor, but I suspect it is a LM334 reference current generator instead.
My revision is a bit different unfortunately, but this is what it looks like. There is a chance that D1 and Q1 will be the same part.
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Probably D1 and Q1 are the same.
Thank you for the picture !
D1 is the "adjustable zener diode" TL431, more specifically, TL431CZ version of it in TO-92 package, by some manufacturer unknown to me (the stylized S letter). Because I don't know the manufacturer, it is quite impossible to know the tolerance of the part, whether it is 2%, 1% or 0.5%.
Q1 is bog-standard 2N3904 NPN transistor in TO-92 package.
wrote:some manufacturer unknown to me (the stylized S letter)
90% sure it's Signetics. It's not /quite/ the same as my Signetics parts though, so could be wrong.
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I found the same S431 diode on a crappy HMC ISA VGA.
But the acumos still not working.
It starts but sundenly the screen goes black with the message "out of sync", even in the bios.
If you are connecting it to VGA port of modern TFT monitor, please make sure (read the manual) that it supports 70Hz formats, because many modern TFTs don't.
