113

Feb 15, 1968

12:30

During our maintenance period this morning we
ran mechanical margins on the Balun boards in CORE 0,
1, 2, & 3. We used High-Speed Checkerboard for the
tests. The following Balun boards caused errors (all
were fixed by "erasing" their contacts):

CORE 0	CORE 1	CORE 2	CORE 3
J14	J2	J16	(No Failures)
J5
J9
K5
K3

We also re-tested the two Balun boards that
were tested last Monday (see Pg. 89 + 75). The board
with the re-soldered eyelet again worked without failing.
(Section 4 was orginally bad.) The other board (the one
with section 13 bad) failed once; but we were unable
to make it fail again. I don't think that we can
send it to DEC for repair until we can see repeated
failures (DEC has already sent it back to us once with
a "no problems found" sign on it.)

During the above mechanical margin tests (above)
we re-aligned the pinch rollers on the 545 to try to
correct the errors that we got on the MGTST
last night (see pg. 94).

I called Clarence Cichon, the DEC Field Engr., and
told him about our problems with DTA4 (see pg. 93).
He suggested that we interchange the relay boards in
DTA4 with one in another unit. After the Balun board
test we exchanged the head relay board in DTA 3 + 4 with
the one in DTA 1 + 2. Before making the exchange we
repeated the EXDATA test that Steve ran last
night on DTA 4: It repeated! After exchanging the head
relay boards, we ran EXDATA again and found that DTA4
still failed. DTA2 (which now has DTA 4's old head relays)
did not fail with EXDATA. The above EXDATA tests were