Thanks Alan, you make some interesting observations.
I did notice the references at the links you provided but as you say they are not the same and the original WE schematics must be out there somewhere, hence my reach out here on stardot. Here's hoping the right enthusiast logs on.
Fault finding becomes easier if you have the original schematics but not impossible if you don't.
Since my last post I have 'hooked' up the 80186 co-pro board internally in my M128 and it announces itself on power on so I suspect all is well there.
This points me to a fault on the internal WE cct board. I have no 'power on' light on the front panel on the WE adapter but can also confirm that there is 18V coming from the internal transformer to the LS78SO5CV voltage regulator and 5V is present on the output pin of the voltage regulator.
I checked the BXZ79C3V9 zener diode and I'm not convinced is is giving a good a reading - I have a replacement in the post.
My next steps will be to install the new zener diode, remove the internal WE cct board from the case, hook up an external 5V and have a poke around to see where the 5V is failing.
Regards Ron.
I did notice the references at the links you provided but as you say they are not the same and the original WE schematics must be out there somewhere, hence my reach out here on stardot. Here's hoping the right enthusiast logs on.
Fault finding becomes easier if you have the original schematics but not impossible if you don't.
Since my last post I have 'hooked' up the 80186 co-pro board internally in my M128 and it announces itself on power on so I suspect all is well there.
This points me to a fault on the internal WE cct board. I have no 'power on' light on the front panel on the WE adapter but can also confirm that there is 18V coming from the internal transformer to the LS78SO5CV voltage regulator and 5V is present on the output pin of the voltage regulator.
I checked the BXZ79C3V9 zener diode and I'm not convinced is is giving a good a reading - I have a replacement in the post.
My next steps will be to install the new zener diode, remove the internal WE cct board from the case, hook up an external 5V and have a poke around to see where the 5V is failing.
Regards Ron.
Statistics: Posted by RonT — Fri Nov 08, 2024 8:52 am