[DSP-10] U107 Voltages

[Yamamoto Jiro]

Hello Bob,

> What voltages do you see on U108 QA to QH?  In receive, I believe 
> only QC (U108-2) should be 5V and the others 0V.  What success are 
> you seeing with programming the  PLL frequency synthesizers?

As to the U108 voltages, I observed that only pin 2 was 5V and other 
pins were 0V. They all are same as you pointed out. Both of the PLLs 
are not working. I tried your PLL diagnostic program, udiag2.exe, and 
the red LED did not go out. It was keeping on. After checking the 
U104-7 and U7-11 voltages, I found that both of the PLLs was not 
locked. Here are the observed voltages after loading udiag2.exe;

  U107-15  0 V
  U107-1   0 V
  U107-2   0 V
  U107-3   4.7 V
  U107-4   0 V
  U107-5   0 V
  U107-6   0 V
  U107-7   4.7 V

  U108-15  0 V
  U108-1   0 V
  U108-2   5 V
  U108-3   0 V
  U108-4   0 V
  U108-5   0 V
  U108-6   0 V
  U108-7   0 V

  R110 1.7 V
  R59 1.4 V

  U104-3 5.0 V
  U104-4  5.0 V
  U7-16 4.9 V
  Across R44 0.13 V
  U105-1 In 1.5 V
  U105-3 Out 2.0 V
  U106-1 In 1.4 V
  U106-3 Out 3.8 V
  U8-1 In 1.1 V
  U8-3 Out 2.9 V
  U9-1 In 2.1 V
  U9-3 In 3.5 V
  U104-7  2 V    
  U7-11 2.4 V

 D1-A1 0.79V
 D2-A1 0.8V

This time (udiag2.exe) U107 seems to work properly while it does not 
under running UHF3 and UHFA!!! Anyway I need to investigate the PLL 
problem more. I am going to do it later with my new scope!

- Jiro, JQ2LMG