I recently added 'check the crystal is oscillating' to my list of basic checks.. Can you scope it and see if you have 2.4MHZ clk?
On Tuesday, October 13, 2020, Charles Hudson <clh...@gmail.com> wrote: > My Model 100 came to me with some problems and I have addressed what I can > (replaced memory backup battery and the usual capacitors, for example) but > this one has me stumped: After reliable service for more than a year, a > few months ago it simply would not light up. I hit the reset button, of > course, and then checked the PSU voltage and replaced the AAs as first > steps. I varied the display pot to see if it had been moved accidentally. > None of this solved the problem. > > Once before it had displayed this problem and I had solved it then by > splitting the case and unplugging / replugging the display cables. I took > it apart again and today after reassembly I inserted a fresh set of > batteries. I must have left the power switch "on" because when I turned it > right side up I saw some characters on the display. Not the usual menu, > though. > > So I pressed the reset button, and the usual menu appeared , with a prompt > below that seemed to relate to the code for the DVI: "Select ..." I > pressed the reset button again, and the display went blank. I shut down, > took out the batteries and turned off memory backup power for about 15 > seconds, replaced batteries, enabled memory power and powered up. Still > blank. > > I checked my reference materials because I faintly remembered there is a > cold-start sequence. I found it on line, at last: SHIFT+CTL+BREAK held > down together, then press RESET. That didn't work either. No sign of life. > > I'm posting here in hopes someone has run across this problem and can > diagnose it or suggest a direction for investigation. Thanks for any > suggestions. > -CH- > > > > > <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail&utm_term=icon> > Virus-free. > www.avast.com > <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail&utm_term=link> > <#m_-680253058579994654_DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> >
