Hello all! I've been collecting classic computers for quite a while now, but I only recently found myself scratching my itch to get into the Model 4. I really only collect computers that I have some past experience with, so this is one more that passes into my collection.
I recently acquired a Model 4 gate-array version that was sold as is - not working. I've managed to diagnose the problem down to a bad Timing chip (4.1.1) and for the gate-array versions this is a bit of a dead end. I actually designed a mezzanine board that reintroduces the main crystal oscillator functionality to restore PCLK, but unfortunately it seem the damage of the Timing chip is deeper and affects most of the other clocks generated by this chip.
So this problem leads me here looking for people who are selling either parts to systems, motherboards or just general NOS. I'm an old hat at Ebay, and have no issue purchasing donor systems from there or Ecyclers. I'm just trying to get a full handle on what resources more experienced TRS-80 enthusiasts have in their arsenal.
Anyhow, thanks for you time! TM
I recently acquired a Model 4 gate-array version that was sold as is - not working. I've managed to diagnose the problem down to a bad Timing chip (4.1.1) and for the gate-array versions this is a bit of a dead end. I actually designed a mezzanine board that reintroduces the main crystal oscillator functionality to restore PCLK, but unfortunately it seem the damage of the Timing chip is deeper and affects most of the other clocks generated by this chip.
So this problem leads me here looking for people who are selling either parts to systems, motherboards or just general NOS. I'm an old hat at Ebay, and have no issue purchasing donor systems from there or Ecyclers. I'm just trying to get a full handle on what resources more experienced TRS-80 enthusiasts have in their arsenal.
Anyhow, thanks for you time! TM
