[drakelist] DR-7 Display

[Mike Williams]

Thanks to all who offered advice on the digital display on my TR7 which was ( is) going bonkers.  The problem was that after an hour of warm up the display would start to display random digits  very rapidly.  The radio was still on frequency.  To complicate matters, I tried the counter function with a wire in the back of the ext  counter connector and switch set to EXT. for the external counter function.  Sometime the counter display worked properly with a 144 MHz signal input and sometimes not.  Tested dc voltages and tried to signal trace but my scope's bandwidth prevented any solid measurements.  Finally isolated the problem down to U9013 on the DR7 board by blasting it with freeze mist; repeated this test numerous times with the same results.  Looks like a thermal intermittent.  Here is the question;  anyone know where I  can find this chip?  MC 10138 P is stamped on the top of the case and the Drake parts list just calls  it a 10138.  I have searched a few electronics sites with no avail.      Thanks much,   Mike W4DL