Sony DVP-S335 Service Manual page 70

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 ad-
dress 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 al-
ready 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. How-
ever, the message uses same template, and accordingly ex-
change Address and Data when reading. The following dis-
play, 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 (IC104) are copied
to all areas of RAM (IC504, IC505) connected to the AVD
(IC502) 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.
(6-3) 1930 SP
ROM → AVD RAM → Video OUT
Error: Not detected.
The data including sub picture streams in ROM (IC104)
are transferred to the RAM (IC504, IC505) in AVD (IC502),
and output as video signals from the AVD (IC502).
They are output from all video terminals (Composite, Y/C,
Component) except EURO AV terminal.
7. Video
(7-2) Color Bar
AVD color bar command write → Video OUT
Error: Not detected.
The command is transferred to the AVD, and the color bar
signals are output from video terminals.
They are output from all video terminals (Composite, Y/C,
Component) except EURO AV terminal.
(7-3) Composite Out
EURO-AV Composite video output check
AVD color bar command write → Video (EURO-AV Com-
posite) OUT
Error: Not detected.
With the Component of video output turned off, the color
bar signals are output from the EURO-AV terminal.
(7-4) Y/C Out
EURO-AV Y/C video output check
AVD color bar command write → Video (EURO-AV Y/C)
OUT
Error: Not detected.
With the Y/C of video output turned on, the color bar sig-
nals are output from the EURO-AV terminal.
(7-5) RGB Out
EURO-AV RGB video output check
AVD color bar command write → Video (EURO-AV RGB)
OUT
Error: Not detected.
With the RGB of video output turned on, the color bar sig-
nals are output from the EURO-AV terminal.
(7-6) Component Out
EURO-AV Component video output check
AVD color bar command write → Video (EURO-AV Com-
ponent) OUT
Error: Not detected.
With the Component of video output turned on, the color
bar signals are output from the EURO-AV terminal.
(7-7) Euro AV Through
Euro-AV2 input check.
Check video and audio signal pass through from Euro-AV2
to Euro-AV1.
Error: Not detected.
6-3