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Ref: DS989-DSP-2
TX-DS989 With THX-ULTRA-2 Addition or omission of parts.
When servicing the DSP of TX-DS989 with
the optional THX ULTRA-2 upgrade, make
sure to refer to this page as well.
Do Not attempt to modify the hardware of a none
Preprocess DSP
THX-ULTRA-2 unit assuming THX-Ultra will work. The
upgrade requires software also. Since the upgrade is sold
separately as an option, this information must be treated as
supplemental technical information for those units having such Q721
an upgrade already in place.
Parts location ID listings in Blue block at the top are for Q721 corresponding to PIN 1~6
and 40 ~ 44. The parts location listings within the yellow block correspond to the SM
components associated to Q721 pin# 18 ~ 28. As the arrow indicates, a wire from a
removed R768 solder landing that connects to IC Q761 pin #22 location (below) is
connected to R745 which is also connected to pin#3 of IC Q721.
Note: All connections at Q761 are in direct relation to the IC pins while at Q721
connection will be through the referenced resistor which is in series to the IC pin.
Jumper wire from Q761 Pin#22 to Q721 pin R745 of Pin
mostly black in color.
Post processing DSP IC Q761
Q761
R768, R769 and R770 may be found to have been removed following the
optional THX ULTRA-2 upgrade. Jumpers are in place as illustrated in the
picture with Red and Yellow lines.
R768 Removed R769 Removed R770 Removed