Re: HP29C strange behavior - IT WORKS ! Message #12 Posted by Alberto Fenini on 15 Feb 2010, 8:02 a.m., in response to message #11 by Eric Smith
Thank you guys, that now brings me back to the other one. I'll load some pics later today. The unit now working is the one that originally had the "white" chips. When turned on, showed always the some number. Since this is the older, I started reworking on the other one, the one that showed some highlighted zeroes on the display. Took away all the chips, the powersupply board, cleaned throughly in and out and polished to get the board to shine conditions. (well, you'll see the pics). To my surprise, when I have resoldered all the components, except the ram chips which I have installed on the other unit, this was not even turning on anymore. My guess is that the powerunit, has some bad contacts. Differently fomr the other, which has the power-involved-components directly mounted on the board, this has the components soldered on a mini board which is then connected to the mainboard. Since the machine was showing something before, I'd like to bring it back at least to that condition and then start some investigation. Does anyone has ever tried to feed power to the machine bypassing those components ? Take care Alberto
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