Emax

Hi guys,

 My Emax hasn't been function again lately. I saw a posting by Jimmy Moore with a link to a german site about using an AT PSU. The description of the LCD corrupting and LED blinking is what struck me. My LCD goes blank, sometimes with some corrupt text visible, there is a whine that is comeing from the area of the keyboard by the LCD, and also all the LEDs light up and a CRC message can appear though this happens inconsistently.

 My question is what is the acceptable voltage variance? The diagnostics document I have say the VR1 can have +/- 5% variance, so on the required +5VDC a range of 4.75-5.25 is with in specs.

 Also, someone mentioned that the LCD (emulator_island?) that the LCD can make this whine, but to your knowledge will this cause the other problems?

Thanks

Emax Specs
Verify +12V on orange wire. 
 
Verify +SV on yellow wire. 
 
Verify -l2V on purple wire. 
 
Verify + 10V on pin 3 of Q2.  

My Test Results20DCV meter setting
At psu connector                 at board connector
orange 11.94V    11.94V
purp  -11.9V         -11.9V
yellow  4.96V      4.94V


Floppy
orange 11.94  Yellow 4.94


200m meter setting
Floppy
green - 41    blue/Purp/Wht - 5.1

Q2 visible circuit path pin 
1 - 10.04
2-11.93

3-10.72 


      

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