![background image](http://html.mh-extra.com/html/sony/ss-cm90/ss-cm90_service-manual_1329653021.webp)
20
HCD-M90
(4-3) DSP Driver Test
Test signal data
→
DSP driver
Error: Not detected.
Caution: Do not conduct this test with a mechanical deck
connected.
The maximum voltage is applied to the servo driver IC
(IC401). If mechanical deck is connected, the motor and
optical pick-up could be damaged. Disconnect mechanical
deck following the output message, then enter specified 4-
or 5-digit number from the remote commander, and press
the
[ENTER]
on the remote commander. The test is con-
ducted only when the input data accord. Check the output
level, then press the
DVD
>
on the remote commander
to finish the test. This test is skipped if “All” is selected.
Supplement: How to disconnect mechanical deck
Disconnect flat cables connected to the CN009 and CN010
of DVD board. Also, disconnect harness from the CN402.
5.
Supply
Caution: Do not conduct this check with a mechanical deck
connected.
An access is made to the stream supply and servo control
IC (IC302) and external RAM (IC303) using check data.
If mechanical deck is connected, the motor and optical
pick-up could be damaged. This check is also executed
by the “All” menu item.
Supplement: How to disconnect mechanical deck
Disconnect flat cables connected to the CN009 and
CN010 of DVD board. Also, disconnect harness from
the CN402.
(5-2) ARP Register Check
Data write
→
read, and accord check
Error 08: ARP register write, and read data discord
Data 0x00 to 0xFF are written to the TMAX register (ad-
dress 0xC6) in ARP (IC302), then they are read and checked.
(5-3) ARP to RAM Data Bus
Data write
→
read, and accord check
Error 09: ARP
↔
RAM data bus error
Data 0x0001 to 0x8000 where one bit each is set to 1 are
written to the address 0 of RAM (IC303) connected to the
ARP (IC302) through the bus, then they are read and
checked. In case of discord, written bit pattern and read
data are displayed. If data where multiple bits are 1 are
read, the bits concerned may touch each other. Further, if
data where certain bit is always 1 or 0 regardless of written
data, the line could be disconnected or shorted.
(5-4) ARP to RAM Address Bus
Data write
→
other address read discord check
Error 10: ARP
↔
RAM address bus error
Caution: Address and data display in case of an error is
different from the display of other diagnosis (de-
scribed later).
Before starting the test, all addresses of RAM (IC303) are
cleared to 0x0000. First, 0xA55A is written to the address
0x00000, and the address data are read and checked from
addresses 0x00001 to 0x80000 while shifting 1 bit each.
Next, the data at that address is cleared, and it is written to
the address 0x00001, and read and checked in the same
manner. This check is repeated up to the address 0x80000
while shifting the address data by 1 bit each. If data other
than 0 is read at the addresses except written address, an
error is given because all addresses were already cleared to
0. In this check, the error display pattern is different from
that of other diagnosis; read data, written address, and read
address are displayed in this order. However, the message
uses same template, and accordingly exchange Address and
Data when reading. The following display, for example,
### Syscon Diagnosis ###
5-4. ARP to RAM Address Bus
Error 10: ARP - RAM Address B
Address
: 0000A55A
Write Data : 00000000
Read Data
: 00080000
Press NEXT Key to Continue
Press PREV Key to Repeat
_
shows the data 0xA55A was read from address 0x00080000
though it was written to the address 0x00000000. This im-
plies that these addresses are in the form of shadow. Also,
if the read data is not 0xA55A, another error will be present.
(5-5) ARP RAM Check
Data write
→
read, and accord check
Error 11: ARP RAM read data discord
The program code data stored in ROM are copied to all
areas of RAM (IC303) connected to the ARP (IC302)
through the bus, then they are read and checked if they ac-
cord. If the detail check was selected initially, the data are
written to all areas and read, then the same test is conducted
once again with the data where all bits are inverted between
1 and 0. If discord is detected, faulty address, written data,
and read data are displayed following the error code 11,
and the test is suspended.
6.
AV Decoder
(6-2) 1930 RAM
Data write
→
read, and accord check
Error 13: AVD RAM read data discord
The program code data stored in ROM (IC108) are copied
to all areas of RAM (IC504, IC505) connected to the AV
decoder (IC503) through the bus, then they are read and
checked if they accord. Further, the same test is conducted
once again with the data where all bits are inverted between
1 and 0. If discord is detected, faulty address, written data,
and read data are displayed following the error code 13,
and the test is suspended.