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Monday, March 28, 2016

6:43 PM

POWER-SUPPLY TESTS

POWER-SUPPLY TESTS
Mod. 33, 35/40, 56/57, 76/77, 85, 90 and 95
The Problem: You have a Mod. 33, 56/57, 76/77, 90 or 85 / 95 and want to test the power-supply.
Bad luck: these power-supplies are switched electronically over the systemboard and have no AC-switch. What if the board is dead or the tiny little switch in the front-panel is broken ? Isn't there a way to test the power-supply without the system around ?The Solution: Yes - it is possible to test these units. Look in this page.

Mod. 95 Power Connector
                     3  6  9  12 15 18 21
                    ----------------------+
          Notch-- /  o  o  o  o  o  o  o  |
            +---2 |  o  o  o  o  o  o  o  | 20
            |     |  o  o  o  o  o  o  o  |
            |     +-----------------------+
            +--------1  4  7  10 13 16 19



           GND    +Pin   Voltage  DC(min)  DC(max)
         ------+-------+--------+--------+--------
            5  |    3  |   +5V  |  +3.7  |  +6.2
            5  |    4  |   +12V |  +9.0  |  +15.0
            5  |    7  |   -12V |  -9.0  |  -15.0
         ------+-------+--------+--------+--------

[Fig. 1: Connector on PS/2 Mod. 85, 95 and 3511 power-supply]
If you have opened the cover and removed the power-supply, connect the power-cord back to the unit.
Then short-circuit the pins 1 and 2 on the power supply.The power-supply cooling fan must come up almost immediately - if you hear just a tiny clicking noise from the unit and have the short checked again for a good connection the power-supply is defective and has to be replaced.
If the built-in fan comes up, check the 3 testing points for their appropriate voltages.
If they are within the given range the power-supply appears to be functional.

Mod. 90 Power Connector
              9  8  7  6  5  4  3  2  1
            +-----------------------------+
            | ## ## ## ## ## ## ## ## ##  |
            ++                          +-+
             +--------------------------+
     
              be be rd rd rd rd rd rd bl
  
                          P1

                 +--+
                 V  V
              9  8  7  6  5  4  3  2  1
            +-----------------------------+
            | ## ## ## ## ## ## ## ## ##  |
            ++                          +-+
             +--------------------------+

              yw wt bl bl bl bl bl bl or

                          P2

           be = Blue, rd = Red, yw = Yellow,
           wt = White, bl = Black, or = Orange


           GND    +Pin   Voltage  DC(min)  DC(max)
         ------+-------+--------+--------+--------
     P1     1  |    2  |   +5V  |  +4.8  |  +5.25
            1  |    8  |   +12V |  +11.5 |  +12.6
         ------+-------+--------+--------+--------
     P2     2  |    1  |   -12V |  -11.5 |  -12.6
         ------+-------+--------+--------+--------


[Fig. 2: Connectors on PS/2 Mod. 90 power-supply]
If you have opened the cover and removed the power-supply cables P1 and P2, connect the power-cord back to the unit.
Then short-circuit the pins 7 and 8 on the power-supply connector P2.The power-supply cooling fan must come up almost immediately - if you hear just a tiny clicking noise from the unit and have the short checked again for a good connection the power-supply is defective and has to be replaced.
If the built-in fan comes up, check the 4 testing points on P1 and P2 for their appropriate voltages.
If they are within the given range the power-supply appears to be functional.

Mod. 33, 35/40, 56/57, 76/77 Power Connector
                 +-----------------------+
                 |+---+ +---+ +---+ +---+|
                 || # | | # | | # | | # ||
                 || # | | # | | # | | # ||
                 || # | | # +-+ # | | # ||
                 |+---+ +---------+ +---+|
                 +-----------------------+
                    1     2     3     4

                            P1

                         +---+
                         V   V
                       7 6 5 4 3 2 1
                     +---------------+
                     |               |
                     | # # # # # # # |
                     +++-----------+++
                      ++           ++
                            P2


 

           GND    +Pin   Voltage  DC(min)  DC(max)
         ------+-------+--------+--------+--------
     P1     4  |    1  |   +5V  |  +3.75 |  +6.25
         ------+-------+--------+--------+--------
     P2     6  |    7  |   -5V  |  -4.75 |  -5.5
            6  |    1  |   +12V |  +9.0  |  +15.0
            6  |    5  |   -12V |  -9.0  |  -15.0
         ------+-------+--------+--------+--------

[Fig. 3: Connectors on PS/2 Mod. 33,56/57,76/77 power-supply]
If you have opened the cover and removed the power-supply cables P1 and P2, connect the power-cord back to the unit.
Then short-circuit the pins 6 and 4 on the power-supply connector P2.The power-supply cooling fan must come up almost immediately - if you hear just a tiny clicking noise from the unit and have the short checked again for a good connection the power-supply is defective and has to be replaced.
If the built-in fan comes up, check the 4 testing points on P1 and P2 for their appropriate voltages.
If they are within the given range the power-supply appears to be functional.

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