Radio Shack TRS-80 Service Manual page 50

5-Meg Hard Disk Service Manual
®
POWER
SUPPLY
Figure
8*
Test Set-Up
Section
II
Visual Inspection
Check power supply for any broken
,
burned, or
obviously
damaged components
.
Visually check fuse resistor
,
if
any
question check with ohmmeter
LOAD BOARD VALUES
SAFE
MAX
SAFE
JTPUT MIN
LOAD
LOADR
LOAD POWER LOAD
LOAD
R
LOAD POWER
+5
0.45
A
11.11
ohm 5W
2.5A
2
ohm
25W
+12
1.3A 0.40
ohm 8W
2.02A 24.24
ohm
BOW
-12
120
ohm
2W
Table
1*
Load Board Values
Start-Up
Load power supply with minimum load
as
specified om Table
1.
Bring power up slowly with Variable Transformer while
monitoring +5 output with scope and
DVM.
Supply should start
with approximately 40-60 VAC applied and should regulate
when
95
VAC
is
reached.
If
output
has
reached
+5 volts, do
a
Radio
JiaeJt
-
48
-