IBM System/370 145 Reference Summary page 107

INITIAL REGULATOR ADJUSTMENT
FOR POWER UP PROCEDURE
Use this procedure when you are not able to power
sequence or get memory voltages or when TR401-V2,
TR202-V2, TR102-V2 or V4 circuit breakers trip. After
initial settings and power sequences up properly, all regu-
lators must be properly adjusted.
Tri-level Regulator
Power Up Procedure
A Tri-level regulator is +1.25, -3.00 and 7 volts (on B-gate
CPU stage 1 and 2 for memory).
Go to CE Over-ride Mode
*Trip Bias Circuit Breaker Single Handle
CP104 Stage I
CP404 - Stage 11
CP203 - MSF
Pull Start Wires off of +1.25, -3. Regs 103 E 11 Stage I CPU
201 E11 MSF
404 E 9 Stage 11 CPU
+7V. Regs 106 E12 Stage I CPU
402 E 12 Stage 11 CPU
202 E12 MSF
Set all 2V Regs to 2.171V. (Note: If not adjusted to
2.171, other supplies will have
to supply more current and
perhaps will trip breakers.)
B-Gate and MSF
B-Gate and MSF
B-Gate and MSF
MSF Only
A2K2B04 2.171 V
B2K2B04 2.171V
C2K2B04 2.171V
C3K2B04 2.171V
*Now put Bias Breaker that was previously tripped to
the on position. Leave start wires off.
Measure DC Outputs Stage I
MSF
+1.25 A2K2D03 for
- 3.00 A2K2B06
+ 7 .00 A2K2G09
Power Down!
.31V
.6V
1.5V
Put respective start wires back.
Bias breaker is on.
Power up adj +1.25, -3, and
+7 volts.
9.5
Stage 11
OV Initial Volt.
OV Initial Volt.
1.5V Initial Volt.
(If not at this initial
value, adjust by varying
voltage adjustment
potentiometer. If un-
attainable, replace
regulator card. If that
does not fix it, replace
the regulator.)