Fitting a HAPN-T V2.0 4800 board to a Paccomm Tiny 2 Mk II, V1.7

Modifications to the PACCOMM Tiny2 Mk II Rev 1.7

Some of these mods are necessary to connect the modem on J5, some change the on board pre-emphasis and others are to fix PACCOMM's design faults. In my case, the circuit diagram supplied with the TNC did not accurately reflect the actual board implementation.

While you are at it, you might check if your board is one of the many with a production fault. The C23 + terminal should connect to U20-15 (ignore the overlay and actually check the tracks - the overlay is incorrect in the faulty units).

Tiny2M201.jpg (160202 bytes)


  1. Cut the track from J5-11 to J5-12
  2. Cut the track from J5-16 to J5-17
  3. Cut the track from J5-21 to J5-22
  4. Cut the track from the jumper JPR on top of the board just in front of C18 (the track does not connect to C18).
  5. Cut the track on the bottom of the board between U11-3 and the nearby via hole
  6. Run a wire from JPR-2 to the via hole on the cut track
  7. Run a wire from U10-1 to U11-3
  8. Run a wire from JPR7 to J5-16
  9. Cut the track under the board from S2 near P3-1 (the track does not connect to P3)
  10. Remove R11 and replace it with a jumper
  11. Remove C8 and replace it with a jumper
  12. Set JPL to NORMAL
  13. Set JPR to 1200
  14. Remove JPA
  15. Remove JPD
  16. Remove JPRA
  17. Replace C27 with 0.01uF
  18. from J5-11 to J5-12

Tiny2M202.jpg (153568 bytes)

Modifications to the HAPN-T


  1. Install a 26 pin header
  2. Run a jumper from U6-2 to U6-14
  3. Run a jumper from J4-2 to J102-5
  4. Run a jumper from J4-21 to J102-1
  5. Remove the 2 pin header and replace it with a 90 degree 2 pin header
  6. Install a switch on the front or rear panel and wire it to a 2 pin header plug, and fit to the above header

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