IBM 1620 Manual page 35

15) Ground A2
D1~:f.-.-
collector pullover punch
Trans Accu Latch.
16) Single cycle UT ring for A 1B1 to A2B2 transfer -
A1B1 and A2B2lights should be on for all positions.
17) Replace Relay 32.
18) Run any card with all 80 columns punched through
the punch feed (any punches).
19)
Sing~e
cycle UT ring for RB-2 to A2B2 transfer
(RB-2, A1B1 and A2B2 lights should be on for all
positions) •
20) Again single cycle UT ring to check RB-2 to A2B2
transfer (RB-2 and A2B2 lights should be off and
A1B1 lights should be on for all positions).
Stop on Error - IBM 1622
For highly intermittent trouble experienced in comparing
circuits on the 1622, the following circuit can be wired
temporarily. Itwill stop the clock in the UT ring posi-
tion and scan ring position in which the failure occurred.
To check read trouble, it is necessary to gang punch a
deck of cards from one given card (preferably an error
card) having random punching in it. Trans Accu
operation (Test 3) can only be checked with cards
having a single punch per column.
To check punch trouble, it is only necessary to punch
repetitively from a given area of memory having infor-
mation similar to that described in the previous para-
graph. (See Page 3.39)
CHARTS
Pages 5.40 through 3.43 are improved timing and
function charts for 1620-1622 transfer operation.
3.29