Ericsson LBI-31511B, Maintenance Manual, Page: 4 / 18

MICROCOMPUTER SOFTWARE (U705)
The latest software package is a 19A703244P23 or a
19A703868G5; replacing the following packages:
Narrowband Wideband
19A703244P10 19A703244P21,22
19A703241G3-8 19A703868G2-4
PROGRAMMING TIPS
When programming with the Suitcase Programmer or a
Personal Computer, Jumper P707 (if present on Negative
Ground System Boards only) must be removed. If programming
the S950/S990 Control Unit for download to the radio, P703 on
the rear of Control Unit must be disconnected to isolate Advance
Change Pulse Line.
When the 4EX22A10 Hand Programmer, Jumper P706
(Negative Ground T/R/S Boards) must be removed (to discon-
nect D720), or lift one end of D720 on Floating Grd T/R/S
Boards.
ALIGNMENT
After the radio has been programmed with new user fre-
quencies, the radio re-alignment procedure is as follows:
UNDER SYNTHESIZER AND TRANSMITTER
ALIGNMENT PROCEDURE
1. Check 9 volt regulator.
2. Adjust the synthesizer transmitter VCO.
3. Adjust the synthesizer receiver VCO.
4. Tune the exciter.
5. Adjust transmitter power amplifier.
6. Set the reference oscillator frequency (one setting for
both transmit and receive).
UNDER RECEIVE ALIGNMENT SECTION
1. Adjust local oscillator-buffer injection.
2. Adjust front end.
3. Adjust IF selectivity.
4. Adjust FM detector/audio pre-amp.
SERVICE TIPS
CHANNEL GUARD BOARD
When servicing the transmit/receive/synthesizer board it
may be helpful to remove and relocate the Channel Guard board.
Both the Channel Guard board and Channel Guard extender may
be removed and set aside during servicing. While servicing the
radio install P608 to connect VOL/SQ/HI.
MICROCOMPUTER
When servicing the microcomputer/synthesizer circuitry
it is sometimes desirable to force the microcomputer into
specific operating modes. Following are some tips that allow
you to initiate these modes.
•
To force the microcomputer to continually try to
reload the synthesizer. This mode will enable you to
check the serial data, clock, channel change pulse and
enable signals to the synthesizer. Grounding the lock
detect line into the microcomputer at U703-8.
•
To stop the microcomputer from running, disable the
watchdog timer by shorting the collector and emitter
of Q714 and ground the single step line at U705-5.
MICROPHONICS
Synthesized radios tend to be sensitive to shock and
vibration, creating microphonics. The construction of the
DELTA-S, radio with its die cast aluminum frame, cast shields,
and multiple board mounting screws, provides a high degree
of immunity. When removing either printed circuit board or
the shields, note the exact location and position of all mounting
hardware including rubber padding and bracket (if included).
When servicing the radio be sure that no solder buildup
has occurred on the chassis or shield.
To assure a high degree of resistance to microphonics be
sure to replace exactly, all hardware removed. Be sure that all
mounting screws are properly torqued and shields in place.
Refer to Mechanical Layout Diagram.
TEST FREQUENCIES
If the EEPROM is not custom programmed to the custom-
ers specified personality, then a standard test program is pro-
vided. The EEPROM is programmed on channels 1 through
16 including tone and digital Channel Guard and carrier con-
trol timer. Table 1 identifies the programmed test frequencies.
BAND
SPLIT
T/R/S BOARD
(NEG. GRD. ONLY)
T/R/S BOARD
(FLOATING GRD.)
450-470 MHz
470-494 MHz
494-512 MHz
403-430 MHz
450-470 MHz
470-494 MHz
494-512 MHz
403-430 MHz 19D901620G1 (Tin Cont.)
19D901620G2 (Tin Cont.)
19D901620G3 (Tin Cont.)
19D901620G4 (Tin Cont.)
19D901620G5 (Gold Cont.)
19D901620G6 (Gold Cont.)
19D901620G7 (Gold Cont.)
19D901620G8 (Gold Cont.) 19D900920G1
19D900920G2
19D900920G3
19D900920G4
NOTE
Typical voltage readings are provided on the Schematic
Diagram for reference when troubleshooting.
NOTE
Loose or rubbing parts, especially in the VCO area
are particularly sensitive and can cause microphon-
ics. Again be certain all hardware is properly installed
and torqued.
LBI-31511 LBI-31511
3