Philips 22 dc 682 service manual

Page 2

SERViCiNG HINTS

6
sec am

Ali 105 and many other semi-conductors are susceptible
to electrostatic discharges (ESD).

Careless handling during repair can reduce service life
drastically, When repairing, make sure that you are
connected to the same potential as the mass of the set
via a wrist wrap with resistance.

Keep components and tools also at this potential,

SERVICE TEST PROGRAMME

The test programme can be called without first entering
the security code.

DISPLAY TEST

This test is called by switching on the set while keeping
the keys preset-up" and band depressed. A number
of easily recognizable patterns are then displayed in
succession. (see figs. 1a to 1d). If you want to make one
of the patterns visible for a longer time, you only have to
keep any arbitrary key pressed for the required time. The
test is stopped by switching of the set.

SOFTWARE CHECK

in this set are two so called OTP's (One Time
Programmable) uC's applicated. This has been done in
order to be flexible in case of future software changes.
The software check gives the possibility to readout the
ROMcode and to display it. for both the applied uC's.
This is a usefuil feature in case of software related
customer complaints. The format of the readout is as
shown in figure re.

The explanation of the format is given below:

M Next 3 characters refer to the Main chipset
E Main - interface 110 software pair indicator
3 Software release version Main processor
B

Main 110 - Main EEprom software pair indicator

next 3 characters refer to the Interface chipset
interface - Main pC software pair indicator

Software release version interface processor

[Dwi'i'l

interface p0 - interface EEprom software pair
indicator

The 3th and 6th digit should always be matching
otherwise the 1105 in the set cannot communicate
properly with each other.

The microprocessor and EEorom within a chipset should
also match.

The EEprom pair indicator has to be read from the
EEprom iiselves.

This test is called by switching on the set while keeping
the keys "Tune down and Preset clown depressed.
The test can be stopped by switching of the set.

DISASSEMBLY V

- Demouniing the RDS unit IS done by removing two
screws obviously used for securing the bracket. The
lower metal housing part of the unit is removed by
unsnapping the metai snaps.

- After removing first the lower then the upper metal
housing parts, two PCB's, hold together by a plastic
holder, are left.

CS 17 097

The plastic hotder supports the thick-film unit which is
vuinerable.

- Opening the unit is done by iifting the PCB, which
does not contain the thick-film. on the ends indicated
by the two arrows on the white plastic holder.

- Mounting is done in reverse order.

- Measurements on the stereo decoder panel.
To perform measurements on the stereo decoder
panel it will be necessary to remove the tape deck.

- To prevent metal parts from bending the tape deck
may not be removed from the set at the cassette lift.

SECURITY CODE

General

To reduce the risk of theft, this car radio has a built~in
electronic lock. The security code has been entered in
the factory and cannot be changed by the customer. The
security code consists of four figures varying between
"0000" and "9999". The figures are selected by pressing
the a and r keys and are entered by pressing the key B

if the Security Code has been activated and the power
supply is interrupted, the radio will only operate for 5
minutes interrupted by beeps. The radio then mutes. The
Security Code must then be entered. The radio will
operate for a further 5 minutes. again interrupted by
beeps. before confirming whether the correct code was
entered.

it the correct code had been entered, a beep will be
heard and the radio will operate normally. If however an
incorrect code had been entered, a warning tone will be
heard and the radio motes. It is then possible to enter a
code again. This process continues unless the correct
Security Code is entered.

This will happen each time the car radio is switched on
until the correct code has been entered.

Activiting the security code

Proceed as follows:

0 While keeping the button pressed, switch on the radio.
The radio mutes and the displays shows CODE.

Entering the code:

0 Press the .3 button.

0 Press the c or r button until the display shows the first
figure of the Security Code.

0 Press the 5 button again.

0 Press the n or ' button until the display shows the
second figure of the Security Code.

0 Press the 6 button again.

0 Press the ~ or * button until the displays shows the
third figure of the Security Code.

0 Press the 6 button again.

0 Press the ~ or ' until the display shows the fourth
figure of the Security Code.

0 Press the 6 button once more.

Example: Suppose the code is 7349
Action Display

- Press 6
Select with A/' 7
- Press 5 7
Select with /r 7
- Press .3 7
Select with A/' 7
- Press .3 7
Select with A /v 7
- Press 6

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