Posts tagged: transistor

Tempest monitor repair log – WG 6100 color vector monitor rebuild

Status: FIXED

Repair cost: About $50


Symptom:  Monitor dead.  Original 6100, fireworks on deflection board, R100 burned through.

Diagnosis: Low voltage section of deflection board is toast.  Perform cap kit, install LV2000, concentrate on chassis transistors & power transistors on deflection board.


  • 08/02/2009 – Installed cap kit + extra parts, LV2000.  F100 & F101 blow immediately after powerup.
  • 08/18/2009 – Replace diodes, transistors on LV2000.  Replace blown (underrated) D100-103 with 6A2 diodes.  Replace Q603/Q703 on frame.
  • 08/24/2009 – Learn, inspect work, double-check, triple check…smoke test tonight.  Deflection board fixed – we have monitor chatter, but only half a picture.
  • 09/17/2009 – F600 now blowing on powerup.  Replaced blown Q606.  Powers up and runs for about 5-6 seconds with vertical line before F600 blows again.
  • 06/25/2010 – Replaced all frame mounted transistor sockets with new ones.  Monitor now powering up.  Issue with Tempest boardset (link), monitor verified working with another color vector game.


The frame-mounted transistor sockets were most likely causing intermittent/bad connections from the corroded and weakened leafs.  The intermittent connections were eventually leading to the transistors shorting out, causing a domino effect of other parts to fail, or a fuse to blow.  Every time a fuse would blow, the proper thing to do would have been to test all the transistors (on the frame and deflection board) for shorts before continuing.  Replacing all 6 sockets eliminated this issue.

Eventually, the culprit parts were the MPSU07/57 power transistors on the deflection board.  These parts are very expensive and/or hard to find, but I bit the bullet and replaced them all, which fixed the problem.

Gorf repair log – Space Cadet level indicator issue

Status: FIXED

Repair cost:  42 cents

Symptom:  Space Cadet light doesn’t work.

Diagnosis:  Test bulb/sockets, check level section circuits.


  • 12/2/09 – Swapped bulbs, sockets to test in other rank lights that were working (i.e. Space Captain).  Replaced all bad bulbs that were found, verified all sockets were working.  Light still not working.  Tested caps and transistors, found a bad ceramic cap and one bad transistor.  Replaced bad ceramic cap.  No change.
  • 12/3/09 – Replaced TIP-110 transistor, Space Cadet light now works.