Tandy 1000 SL Technical Reference Manual page 206

Star
t-Up
Load power supply with minimum load as specified
i n
Table 1.
Bring up power slowly with the Variable Transformer while
monitoring the +5 output with the oscilloscope and
DVM.
Supply
should start with approximately 40-60 VAC applied, and should
regulate when 90 VAC is reached. If output has reached
5
volts,
do a performance test
on
operating characteristics, if there is
no output, refer to
"NO
output" section.