Repair - ZX Spectrum/Pentagon setup and repair.

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Wild/OHG                                  
                                          
                 PEOPLE!!!                 
                                          
   A misfortune recently happened to me.
My PENTAGON went to the "Land of Eternal"
Hunting", or simply put, he died.            
   I spent a week without a car.  It was
enough time to look for something
problem.                                 
   I'm lucky; on my table, among
the most terrible mess, I discovered
valuable book -"ZX-SPECTRUM (PENTAGON ++)-
DEVICE, SETUP, REPAIR."           
 How and when it came to me - I already
I don't remember. No information about who
I don’t have this book when it was published. On the cover
written: "ROSTOV-on-DON; 1992", and that's it.  
   The repair procedure outlined in this
The book is awesome. Everything is signed before
little things and at the same time brief and understandable.  
 Using this book, how
guidebook, faulty microcircuit I
found it in a few minutes.                 
   Now, as you can see, my computer is working fine, and
I'm ready to bore you again on the pages
"DonNews"and play my favorite "ELITE".
And for those whose “shaitan machine” is still
breathes, I reproduce this book as
an invaluable aid in the most difficult
life situations (we apologize to
owners of other cars, purely
"Pentagon" information).             
   Theory on the structure and operation of PENTAGON-
and I won’t give it (yet, but if
if necessary, let me know).                     
   And one more thing;   preferably this text
print it out, because if the car gets covered,
reading it from disk will be enough
problematic.                            
                                          
                                          
       1. NO IMAGE ON THE SCREEN.       
                                          
   Check the operation of the video controller:
master oscillator D1/4, serviceability
quartz, operation of counters D3, D4, D11, D12.
Check for the presence of horizontal pulses D7/8,
frame pulses D5/8, a mixture of lowercase and
frame pulses on D6/3, D71/11. When
the presence of all impulses should be observed
stable screen synchronization
TV.                               
   For further checks please review
impulses RAS-DЧ5/3 and CAS-DbЗ/11.          
   Information read from memory by
local data bus arrives at
shift register SHIFTRG: D38,D41,D42 and
recorded at high strobe level
LDSCR - element D5/6. The number of pulses is
the number of familiar places in the line is 32. To check
this node, check the pulses first
records D38/11-С18, D41/6, D42/6-С2, D41/9,
D42/9-C1. Then, connecting to a common bus
alternately those board points to which they will be
14th pins of D20-RAM chips are soldered
D25, we should get 32 on screen
flashing vertical stripes (if the stripes
do not blink, then you need to check
flicker generator on element D100.4).When
this should appear on element D42/10
pulses of negative polarity with
duty cycle 8.                            
   To check functionality
RAM chips D26,27 - in addition to connection with
common output wire of 14 of these microcircuits,
must be connected to the common wire 14th
output of any of the D20-D25 chips. At the same time
double icons should appear on the screen
non-blinking stripes. Check similarly
passage of signals from the second line
RAM - D28-D35 chips.                  
   If you have soldered the RAM chips onto the board,
then to carry out the above
testing it is necessary to cut the signal,
arriving at the 15th leg 5b5RU5 (CAS from
D63/3 and D63/11) and apply to the 15th leg on


check time +5B".                      
To be continued, but for now that's all.      
                                          
   P.S. HELP!!! People who have the same
book, but with APPLICATION, contact me,
please. The application is lost, but it contains the most
valuable; namely - OSCILLOGRAMS.