4 PWM - Power Distribution Module

Th fastest check of PWM functionality are the front panel LEDs: they should be all lit except when the writing voltages are expressly disabled by the field system. (To check this condition, you can remove the power cable of IOB at J6: when this cable is removed, all four write voltages and their corresponding LEDs should be lit.)

Measuring the voltages regulated at PWM is made easy with 4mm test sockets at the front panel, compatible with standard ``banana'' plugs widely found in measurement cords.

During the installation you should adjust the variable write voltages of this module. The installation document section ``Checking the PWM'' provides detailed PWM checkout procedures.

If the variable write voltage regulator for WRM~1 or WRM~2 suddenly fails, a quick workaround is available if you have only two WRMs (the initial standard configuration): move the power cable for WRM~1 from J1 to J3 (Write~3), or, for WRM~2 from J2 to J4 (Write~4). Write voltage disable lines work in tandem for 1--3 and 2--4.

PHP - Aluminium heat sink plate

• 6 AMP 206433-1 CPC square flange receptables for socket contacts (power output connectors J1--J6 at front panel).
• 2 AMP 2088000-1 or Thomas&Betts CPC 11 (FEC order number ``240-898'') sealing caps for currently unused WRM power output connectors J3 and J4.
• 3 AMP 206705-1 CPC 13 square flange receptables for pin contacts (power input connectors J7--J9 at rear panel).
• 36 M3x10mm hex screws (ISO 7380 low-profile).
• 36 M3 lock spacers (thickness max. 1.0mm).
• 36 M3 nuts.

The connectors are fixed into front and rear panels with four screws each. No contacts are inserted at this stage.

Crimp contacts first according to AMP instructions---see the leaflet that accompanies the connectors and the crimping tool AMP 169341-1 (for 0.2--0.56mm wires). After crimping cut the wires to the lengths presented below. Strip around 5mm from the wire ends that are to be soldered onto PCB and dip first in Multicore X32-10i liquid flux and then in a solder pot.

For best results use 1.2mm/18AWG solder wire when soldering these power wires onto PCB. 0.7mm/22AWG solder contains too much flux for the large solder pads present on this PCB.

With small AMP 166291-7 (or 66504-9) HD-20 socket contacts (red dot) and 20AWG stranded copper wire (from Alpha cable):

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PWM front -- total length incl. contact + color -- PWB
(The best sequence to wire connector J1-5 pins is: 5, 2, 7, 3, 1.)
J1-1 -- 95mm red    -- J1 (+12V)
J1-2 -- 70mm orange -- J1 (+V VAR, nearest to 4mm test socket)
J1-3 -- 75mm green  -- J1 (-12V)
J1-5 -- 85mm black  -- J1 (RETURN)
J1-6 -- polarizing plug, small AMP 213586-1
J1-7 -- 70mm blue   -- J1 (VHRET)
J2 as J1
J3 as J1
J4 as J1

J5-1 -- 95mm red     -- J5 (+12V)
J5-2 -- polarizing plug, small AMP 213586-1
J5-3 -- 75mm green   -- J5 (-12V)
J5-5 -- 85mm black   -- J5 (RETURN)

(The best sequence to wire connector J6 pins is: 5, 2, 4, 6, 3, 1.)
J6-1 -- 105mm red    -- J6-1 (+5V, square pad, bottom)
J6-2 -- 110mm blue   -- J6-4 (RETURN)
J6-3 -- 120mm green  -- J6-3 (-5V)  (or directly to rear J8)
J6-4 -- 120mm black  -- J6-2 (-5V RETURN)  (or white directly to rear J8)
J6-5 -- 120mm white  -- J6-5 (DISABLE 1)
J6-6 -- 120mm orange -- J6-6 (DISABLE 2)
J6-7 -- polarizing plug, small AMP 213586-1

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With large AMP 163086-2 HD20 pin contact (yellow dot) and 20AWG stranded copper wire (from Alpha cable):

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PWM rear -- total length incl. contact + color -- PWB
J7-1 -- 375mm white -- J7-1 (+20V, square pad, top)
J7-3 -- 370mm red   -- J7-2 (+14V)
J7-4 -- 365mm black -- J7-3 (VHRET)
J7-5 -- dummy pin (crimped with no wire)

J8-1 -- 300mm black -- J7-5 (-5V RETURN)
J8-2 -- dummy pin (crimped with no wire)
J8-3 -- 300mm red   -- J7-4 (-5V)
J8-4 -- 300mm white -- J7-5 (-5V RETURN)
J8-6 -- 300mm green -- J7-4 (-5V)

Alternative for J8 (two wires crimped in large AMP contacts
and the wiring goes directly from rear AMP to fron AMP connector):
PWM rear -- large AMP pin contact, wire, small AMP socket contact -- PWM front
J8-1 -- 25mm white --> continuous wire to the same connector J8-4
J8-4 -- 395mm white -- J6-4 (-5V RETURN)
J8-2 -- dummy pin (crimped with no wire)
J8-3 -- 25mm green --> continuous wire to the same connector J8-6
J8-6 -- 395mm green -- J6-3 (-5V)

PWM rear -- total length incl. contact + color -- PWB
J9-2 -- dummy pin (crimped with no wire)
J9-3 -- 305mm green -- J9 (-12V)
J9-4 -- 295mm red   -- J9 (+12V)
J9-5 -- 300mm black -- J9 (RETURN)

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See the Haystack drawing 4712A103 for a reference description of this cable. Alpha cable 4x20AWG stranded copper wire type ``1896/4C'' is used.

PWM rear panel connector J7 will accept AMP plug 206708-1 with large AMP 163088-2 socket contacts and a standard cable clamp AMP 206966-1. At the Honeywell Unregulated Power Supply end of this cable, AMP Faston lugs 640917-1 (red) are used.

Strip the outer sheath of cable at Honeywell end for about 50mm. Use 70mm clear heat shrink tubing and let about 10mm of tubing extend over stripped wires. Cut wires 30mm after the end of heat shrink tubing and crimp AMP Faston lugs to the three wires.

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PWM rear  -- 1830mm/72" cable --  Honeywell
-------------------------------------------
J7-1 -- white -- TB3-1 (+20V)
J7-2 -- polarizing plug AMP 200821-1
J7-3 -- red   -- TB3-5 (+14V)
J7-4 -- black -- TB3-4 (VHRET)

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See the Haystack drawing 4712A102 for a reference description of this cable. Alpha cable 4x20AWG stranded copper wire type ``1896/4C'' is used.

PWM rear panel connector J8 will accept AMP plug 206708-1 with large AMP 163088-2 socket contacts and a standard cable clamp AMP 206966-1. At the Mark~III Power Supply end of this cable, the standard Haystack design uses AMP 206226-1 plugs with a 206138-1 clamp and 66261-1 extra large pins. The standard pinout is:

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PWM rear  -- 1220mm/48"cable --  Mark III Pwr
---------------------------------------------
J8-1 -- black -- P2/J2-2 (-5V RETURN)
J8-3 -- red   -- P2/J2-1 (-5V)
J8-4 -- white -- P2/J2-2 (-5V RETURN)
J8-5 -- polarizing plug AMP 200821-1
J8-6 -- green -- P2/J2-1 (-5V)
                 P2/J2-4 (dummy pin)

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The Mark~III Power Supply end of this cable is delivered unassembled, because different stations use different connectors in their Mark~III power supplies.

See the Haystack drawing 4712A101 for a reference description of this cable. Alpha cable 4x20AWG stranded copper wire type ``1896/4C'' is used.

PWM rear panel connector J9 will accept AMP plug 206708-1 with large AMP 163088-2 socket contacts and a standard cable clamp AMP 206966-1. At the Mark~III Power Supply end of this cable, the standard Haystack design uses AMP 206226-1 plugs with a 206138-1 clamp and 66261-1 extra large pins. The standard pinout is:

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PWM rear  -- 1220mm/48" cable --  Mark III Pwr
----------------------------------------------
Standard Haystack version:
J9-1 -- polarizing plug AMP 200821-1
J9-3 -- green -- P1/J1-2 (-12V)
J9-4 -- red   -- P1/J1-3 (+12V)
J9-5 -- black -- P1/J1-4 (RETURN)

Local Metsahovi version:
J9 AMP -- J? Vero Trident
J9-3 -- green -- J?-E (-12V)
J9-4 -- red   -- J?-D (+12V)
J9-5 -- black -- J?-F (RETURN)

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Optionally, the Mark~III Power Supply end of this cable can be delivered unassembled, because different stations use different connectors in their Mark~III power supplies. After you have checked and completed the cables ``PWMMKPJ1'' and ``PWMMKPJ2'' for your station, you should document the connector and pinouts used in the ``Station-specific information'' section of the upgrade documentation binder. (A preprinted form is supplied for this purpose.)