DSP-10 from W7PUA: Hints for Assembly and Test
Things to be aware of...
Collected here are hints to aid in the assembly and testing of the
DSP-10. This needs to be used along with the other information, as this is by
no means step-by-step instructions. But use this as a check list to be help
catch problems that will slow down getting everything to work!
In addition to the material on this page,
there are Corrections and Modifications that are listed on the
DSP-10 Page Home Page.
- If you are using the Epson 10 MHz crystal for Y101, rather than the ICM
crystal listed in QST, you will need to add capacitors across C108 and
C108 as described on Parts Page.
- The ground connection to the EZ-KIT Lite board is not shown explicitly.
The negative lead for the power will probably handle the grounding, but two
short ground wires from P3-1 and P3-50 to the box will make sure there is a
good ground for the digital wires. No problem has been reported for the grounding
of the analog lines. The 10 to 20 kHz range is reasonably immune from such
problems. If there is any question, you can catch an analog ground in the
area around J1 and J2 on the EZ-KIT board.
- On the subject of P3. The pin numbering for P3 on the EZ-KIT board is
confusing. This seems to relate to the PCB layout program that was used. Any
reference to P3:2-xx should be P3-xx. The ':2' and ':1' are not needed.
- Be careful in winding the toroids. Too tight and they will crumble
into pieces. The best procedure is to just bring the turns snug. After
the toroid is finished it can be helpful to cover it with "Polystyrene Q-Dope"
(GC Electronics 10-3702).
- By keeping the voltage going to the EZ-KIT to 9 Volts, the temperature
of the U6 regulator on the EZ-KIT is hot, but not excessive, as long as the
overall box is at room temperature. To provide some margin, one can attach a
piece of metal between the regulator and the box. If this is bent at right
angles it can be fastened with machine screws.
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This was revised 22 Dec 01. Bob Larkin, W7PUA