Yamaha HS80M Service Manual page 9

HS80M
4-3 Unsolder soldered parts (22 locations) on the pat-
tern side of IC801 and IC802. (Photo. 1)
4-4 Remove the two (2) screws marked [A] and remove
the heat sink with IC801 and IC802. (Photo. 1)
Remove the two (2) screws marked [B] and remove
IC801 and IC802. (Photo. 1)
4-5 Remove the four (4) screws marked [C], remove the
AMP mounting bracket. The AMP circuit board can
then be removed. (Photo. 1)
HEAT SINK HEAT SINK
SPACER SPACER
AMP mounting BRACKET AMP mounting BRACKET
AMP AMP
[B] [B]
[C] [C]
Photo. 1
5. INPUT Circuit Board
(Time required: about 3 minutes)
5-1 Remove the rear panel assembly. (See procedure 3.)
5-2 Remove the four (4) screws marked [110] and the
screw marked [115]. (Fig. 3)
5-3 Remove the LEVEL knob, the hexagonal nut [E] and
washer [D]. (Fig. 3, Photo. 5)
5-4 Remove the hexagonal nut [F] on the phone type in-
put connector. The INPUT assembly can then be re-
moved. (Photo. 5)
5-5 Remove the three (3) screws marked [G] and remove
the case PWB. (Photo. 3)
The Input circuit board can then be removed.
* The case PWB is not a component of the INPUT cir-
cuit board. When replacing the INPUT circuit board,
remove the case PWB and reuse it.
[A]
AMP mounting BRACKET AMP mounting BRACKET
AMP AMP
IC802 IC802
[C] [C]
IC801 IC801
AMP circuit board AMP circuit board
AMP AMP
<AMP Unit>
CASE PWB CASE PWB
[G] [G]
Photo. 3
HS80M/HS50M
INPUT Circuit Board INPUT Circuit Board
INPUT INPUT
Photo. 2
<INPUT Assembly>
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