Minutes of the HV Board Meeting 
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      Participants: M.Staric, S.Korpar, P.Krizan, U.Uwer
      Time:         09/12/98, 14:10 - 14:50
   
   
   
      Topics: 
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      1. Status of the board production
      2. Further strategies of the HV boards production
      3. Shielding plates
      4. Potting and Testing

       
  
 
  1. Current status of the board production:

     - MC1- boards will be finished (including cables) by Tuesday 15/12.
       They will be brought to Hamburg by Samo or Marco.

     - MC2+/MC1+ board design is almost finished. Boards are foreseen 
       to arrive in Hamburg by end December / beg. January.



  2. Further strategies of the board production:

     - the boards needed for TC1- and PC4- should be done in the 
       "unswapped" (current) design.

     - Samo will produce for one of the 16 types a "swapped" version.
       The design will be send to Hamburg and should be checked
       with respect to the routing of the rylsan pipes: Since there
       are 2 capacitors on the bottom side of the board they might 
       interfere with the routing. 

       Once the details of the routing are fixed he can produce
       the remaining 15 types.


  3. Upper shielding cover:
  
     Marco presented the new design of the shielding cover:

     - 500 mum thick Fr4 plate with an conductive layer  is used
       as upper cover

     - the HV boards are grounded to base plate and upper cover
       with the help of 3 soldered grounding pins 

     A detailed sketch of the grounding in the HV Board region 
     can be found on the Web
     http://www-hera-b.desy.de/subgroup/detector/tracker/
                              outer/electronics/hv/welcome.html



     In addition Marco presented a scheme for the mounting of the 
     boards:

    (1) fold all connecting wires upwards, cut them to appropriate lengths
    (2) put distance holding plate (not shown in the picture) onto the base
        plate
    (3) put all large boards (without small ones), position them such that
        board's soldering pads and anode wires are in line and the distance
        between HV board and G10 endpiece is approx. 2 mm.
    (4) solder the ground pins to the base plate
    (5) fold the connecting wires down to the soldering pads, solder them
    (6) do the HV test (as we did in Zeuthen), disconnect bad wires
    (7) connect small boards, repeat steps (5), (6)
    (8) mount the cover plate, solder the grounding pins
    (9) remove (pull out) the distance holding plate

    The grounding pins will be already soldered to HV boards, with right
    lengths.




  4. Potting:

     Doubts about the need of potting were expressed. In particular
     in case of the "swapped" design the lower capacitor have to be 
     potted. Space problems could be the consequence.

     Nevertheless the possibility of potting is checked with the 
     company. 
     Due to limited time no potting is done for the MC1/MC2 boards.