Test Function; Troubleshooting; Signature Analysis; Introduction - Tektronix DC 5010 Anleitung

reached. If a count greater than or equal to the proper count
has not been accumulated, the error code for that accumu-
lator stage is displayed and the self test sequence stops.
-
An improper count might occur because of a bad counter
chip, a bad readout chip, or a disconnected cable.
NOTE
The signal path starts at the D/A converters and the
cycle must pass through the amplifiers, gating, and
the accumulators. A first bit error (320, 330) may indi-
cate an amplifier, FET or Schmitt error.
7. If the counter integrity test fails for any of the de-
scribed reasons, the D/A converters will be set to -2
V.
The gating (schematic 3), remains in the RATIO B/A func-
Internal signature analysis-this is a microprocessor
driven pattern generator contained in the ROM. This meth-
od will only work when the kernel microprocessor and its
associated ROM, RAM, and connections are functional.
Kernel signature analysis-this requires the use of an
external kernel test service kit (Tektronix part number 067-
1007-00). This method allows qualified service personnel to
test and isolate problems in the kernel of the instrument.
Internal Signature Analysis
The internal signature analysis mode is entered at power-
on by pressing the CHANNEL A TERM button (50 Q) as
power is applied. This mode will not operate if the instru-
ment fails the power on RAM test. Refer to Figs. 8-6, 8-7, 8-
8, and 8-9 in the pullout pages, for the inter~al signatures
setup information for each circuit board.
tion and by applying a signal, that crosses the -2 V Trigger
level settings, to the appropriate channel input, the service
In the internal signature analysis mode, the serial loop is
personnel can trace this signal through the amplifier, gating, easily The START,
and
and accumulator circuits. Also refer to Table 8-2 in the
edge polarities r ~ s t be properly set as shown on the appro-
pullout pages.
priate signature diagram. When the instrument is in this
mode, all segments and annunciators in the display are
TEST Function
The TEST function from the front panel and over the bus
is similar to the Power On Self Test sequence with one ex-
ception. The RAM test is not executed, thereby preventing
the instrument's settings from being lost while in the TEST
function.
TROUBLESHOOTING
The following is a general troubleshooting procedure to
use when the instrument malfunctions.
First, verify that the instrument is properly connected to
the appropriate power module and that this power module is
operable. Then refer to Fig. 8-5, General Troubleshooting
Flowchart, in the pullout pages. This flowchart is a guide for
qualified service personnel to locate various areas of circuit-
ry, depending on the instrument symptoms. It may also refer
the service personnel to the following signature analysis
procedure.
SIGNATURE ANALYSIS
Introduction
The DC 501 0 was designed to be compatible with two
signature analysis methods.
lighted, with the extreme left digit brighter than the other
digits. The pushbuttons are also lighted.
To exit the Internal Signature Analysis mode, the instru-
ment must be powered down and then powered up.
Kernel Signature Analysis
The Digital board microprocessor, U 130 1, is removed
(observing proper static handling procedures) before
making the kernel test.
The kernel signature analysis mode is used to diagnose
problems that prevent the microprocessor kernel circuitry
from functioning properly. It is used with a signature analyz-
er to verify signatures in the kernel circuitry.
Make certain the power module power is off when con-
necting this service kit to the instrument. To make the
DC 501 0 kernel board connections, the GPlB board (A1 4)
must first be removed (refer to Circuit Boards Removal and
Replacement). Then, connect J1002 and J1003 of the Ker-
nel Test board to J1210 and J1211 on the instrument Digital
board (A16), respectively, using the cables and square pin
adapters provided with the kit. Make sure that the cables do