Tektronix DM 5010, Instruction Manual

Page: 241 / 347

Maintenance —DM 5010
Table 7-3 (cont)
Typical Symptoms
Circuit Section— Verification
Hangs up bus, or will not communicate
over bus with controller.
10. GPIB—Connect a 4051 or 4052 to the DM 5010 power module. Turn all
power on. If the message:
NO SRQ ON UNIT-MESAGE NUMBER 43
is received, type:
POLL X,Y;16
where 16 is the instrument address. Short the DM 5010 inputs. Type the
following:
PRI @16: ‘DCV 2"
INP @16: AS
PRI A$
The last line on the controller display should be: 0.; or 0.0001; or —0.0001;. The
instrument does not have to be within specification to verify bus operation.
Before beginning troubleshooting on the selected circuit
section, visually inspect the circuit board for broken,
damaged, or loose components, damaged or shorted circuit
paths, etc.
1. POWER SUPPLY, CLOCK, PON CIRCUITS
a. POWER SUPPLY, Isolation Board, Diagram 4
If verification indicated a +5V malfunction, remove the
Isolation board from the DM 5010, but leave the board con­
nected to the flexible extender cable. Check for +5 V at
J1733-1A or 1B. If +5 V is present, then a load on either
the Main Interconnect board or CPU board is pulling down
the 4-5 V supply.
Check the 3 A fuse on the Isolation board.
Check for 4-5 V at U1000-2. If not present, check
Q1105, Q1104, and PWR (P1031-6B) from the power
module.
Check that VR1216 is not shorted.
b. CLOCK, CPU Board, Diagram 7
Check U1320-37 for a 1 MHz squarewave.
Check U1320-38 and 39 for a 4 MHz squarewave.
c. PON, CPU Board, Diagram 7
Check VR1232.
Check U1230 (all pins).
2. MICROPROCESSOR, CPU Board, Diagram 7
To troubleshoot this circuit, do the following steps or use
a signature analyzer to check the signatures in Table 10A in
the pullout pages.
a. On U1320, check that the address and data lines are
toggling; IRQ, RESET, NMI, and HALT are not stuck iow;
check for clock pulses on pins 37, 38, 39. Check power and
ground to U1320.
Check U1000 and Q1101.
Reinstall the Isolation board.
b. Check power, ground, data, and address lines in the
circuit area including U1235, U1420, U1510, U1520, U1620,
U1720, U1730, U1435, U1430, U1425, U1200, U1300,
U1305, U1400, U1600, U1505, U1220.
ADD JAN 1982
7-11