Liquid Nitrogen Tests of Proposed ROCK Components
         -----------------------------------------------------

                                                              8,9-JULY-1997


Part   Raw Values     On Cable     1st     2nd       3rd       liquid      RT
----   ----------     --------    -----   -----     -----      ------     -----
C1      93.75 nF      121.7 nF    2.968   2.996     3.009       3.026     107.5
C2      95.40 nF      134.2 nF    4.259   4.238     3.952       3.024     117.2
C3      91.91 nF      125.0 nF    5.324   4.228     3.440       3.035     111.1

T1      10.13 uF      10.10 uF    8.386   8.371     8.460       8.488     10.11
T2      10.35 uF      10.33 uF    9.109   8.783     8.489       8.638     10.36
T3      10.15 uF      10.12 uF    9.251   9.073     8.679       8.550     10.15

L1       15.4 uH       16.4 uH     14.7    14.7      14.5        14.6      16.5
L2       15.5 uH       16.6 uH     15.1    15.0      14.9        14.3      16.3
L3       15.4 uH       16.3 uH     15.0    14.8      14.6        14.2      16.3

R1      109.7 ohm     110.1 ohm   112.5   112.4     112.9       112.9     110.1
R2      110.0 ohm     110.3 ohm   112.4   112.5     112.7       113.8     110.3
R3      109.9 ohm     110.2 ohm   111.5   111.9     112.6       113.8     110.2

Ag-Mi   2.478 nF      2.490 nF    2.481   2.481     2.481       2.481     2.493

NP0     2.049         2.063       2.054   2.055     2.055       2.056     2.061



C = Ceramic Capacitor     Sprague  0.1uFd  50Volt Z5U

T = Tantalum Capacitor    Sprague  10uFd 16Volt 20%
                          Part No. 293D106X0016C2T   Date Code 9302


NP0 = Test a single  2.2 nFd  NP0 Ceramic  SMD 1206 capacitor


L = Inductor
R = Resistor
RT = Room Temperature

Ag-Mi = Silver-Mica Capacitor     2.5 nFd   500Volt  5%


Capacitance of the test leads measured   12.7 pFd
Parameters were measured with a Philips RCL Bridge



Test two more 0.1 uFd ceramic Z5U caps just to see the change due
to heating during soldering:

   Cap ID   Raw Value   After Heat   ~5 min later   ~10 min later
   ------   ---------   ----------   ------------   -------------
     C4       94.71       118.4         111.9           110.8  nFd
     C5       91.24       114.4         108.3           105.8  nFd



Test an Yamaichi 68 pin socket.  Measure it, cycle it to LN2 temperature
three times, and measure it again.  There were no measurable changes.
Measuring the length of the 4 sides repeated to 0.001 inch.



24:27-OCT-1997

Made nitrogen temperature tests on the Belden 9930  30 gauge wire, the
AMP connector housings and Elmer's Wonder Bond cyanoacrylate super glue
which holds the twisted pair #30 wires in the 1/8" copper tubes.  This
setup was slowly cooled once and plunge cooled twice with no ill effects.
The Belden wire does not appear too stiff at nitrogen temperature.  The
super glue was still holding fine after 3 cycles even though the inside
of the copper tube had not been cleaned in any special way before the glue
was applied.  No problems seen so far.

Made nitrogen temperature test of the ROCK circuit board.  The test setup
was 7 connections to the double GND planes by 35 mil via's, and 7
connections to the single Analog VCC plane, 4 by 35 mil via's and 3 by
13 mil via's.  Check for both continuity (0.1 to 0.2 Ohm resolution) and
shorts.  Two slow cool downs (30 min) and one fast cool down (5 min).
No problems seen so far.