Service manual hamamatsu, japan 1.507k-033 k printed in japan 2001.08 011592 ga 20010720-17800 contents specifications .............................................................................. 3 panel layout .................................................................................. 3 ci...
2 f-20b important notice this manual has been provided for the use of authorized yamaha retailers and their service personnel. It has been assumed that basic service procedures inherent to the industry, and more specifically yamaha products, are already known and understood by the users, and have th...
3 f-20b specifications panel layout rated output power: 20w speaker: 25cm x 1 controls: volume, treble, high mid, low mid, bass, input level select switch (passive/active) input/output terminals: input, aux in, phones power consumption: 25w/120v (ul, csa) 25w/230v (e, bs) power requirements: u.S. An...
4 f-20b circuit board layout main 1/2 main 1/2 main 1/2 main 2/2 main 2/2 ac cord power transformer block diagram +b +12v -12v -b gnd power amp ic4 ic1 ic3 1 2 3 1 1 4 input fuse fz1 active type tone control power supply circuit power transformer 4 Ω speaker phone aux in cn2 4p cn1 2p cn3 3p cn4 5p ...
5 f-20b disassembly procedure [30] x 4 [60a] [a] backboard speaker pre-main unit pre-main unit (fig.1) main1/2 circuit board needle-nose plier needle-nose plier main1/2 circuit board [p40] [p40] (fig. 2) [30]: truss head screw 4.0x25 mfzn2bl (vn347600) [a]: bind head tapping screw 4.0x25 fcrm3-bl (e...
6 f-20b main 1/2 main 2/2 [p100], [c] [a120] [p60] [p70] [p80] [a140] [p70] [p60] [p40] [p40] power transformer [a120]: hexagonal nut 9.0 12x2 mfni33 (lx200060) [a140]: hexagonal nut 12.0 14x2 mfni33 (es200210) [p60]: pan head screw 4.0x10 mfzn2bl (v7018000) [p70]: hexagonal nut #1 4.0 mfzn2y (vb837...
7 f-20b high mid low mid bass aux in phones power to speaker to main 2/2 cn4 from power transformer to power transformer from ac cord to power sw a' a input gain select volume treble a' a main1/2 circuit board circuit boards main 1/2 (j, u, c): cna-v755470 main 1/2 (h, b): cna-v755480 main 2/2 (j, u...
8 f-20b inspections ic block diagram ba4558 (xo078a00) dual operational amplifier 1 2 3 4 -v 8 7 6 5 output a +v non-inverting input a -dc voltage supply +dc voltage supply output b inverting input b non-inverting input b inverting input a + - + - main: ic1,ic2,ic3 1. Preparation to inspect the main...
F-20b 1 parts list bass amplifier contens overall assembly .................................................................................. 2 pre-main unit ............................................................................................ 4 electrical parts .................................
F-20b 2 overall assembly 50 20 10 c40 c60 c50 c60 c50 c30 c30 a c20 c70 c90 c80 40 30 c100 c110 overall cabinet assembly pre-main unit 60 60a.
F-20b 3 ref no. Part no. Description remarks qty rank rank: japan only *new parts 10 20 20 20 20 30 40 50 50 50 60 60a c10 c20 c30 c40 c50 c60 c70 c80 c90 c100 c110 a -- -- -- -- v 7 4 6 11 0 0 -- -- -- -- vn347600 e t5 0 0 040 -- -- -- xo361a00 vb403600 v 7 4 6 11 0 0 -- v 5 9 6 9 0 0 0 2 1 7 7 0 2...
F-20b 4 a10 a70 a60 a40 a10 a30 a80 a90 a20 p60 p40 p60 p30 p75 p70 p50 p10 p20 p90 p80 a50 p100 p120 p110 a100 a110 a130 a140 a120 amp kit p77 pre-main unit.
F-20b 5 ref no. Part no. Description remarks qty rank rank: japan only *new parts p10 p20 p30 p30 p30 p30 p40 p50 p60 p70 p75 p77 p80 p90 p100 p110 p120 a10 a10 a20 a30 a40 a50 a50 a50 a60 a70 a70 a70 a70 a80 a90 a100 a110 a120 a130 a140 -- -- -- -- v6954800 v7460600 -- -- -- -- v 7 5 11 4 0 0 v7017...
Ref no. Part no. Description remarks qty rank f-20b 6 rank: japan only *new parts v 7 5 5 4 7 0 0 v 7 5 5 4 8 0 0 v 7 5 5 4 7 0 0 v 7 5 5 4 8 0 0 -- -- -- v 6 6 0 9 9 0 0 vv29 1 40 0 ur866100 v z 3 5 3 5 0 0 ur847100 v z 3 5 3 5 0 0 v z 3 5 3 5 0 0 ur866330 vv06 1 20 0 ur865470 vv06 0 60 0 ur865100 ...
F-20b 7 ref no. Part no. Description remarks qty rank rank: japan only *new parts hf456330 hf457330 hf457330 hf458100 hf457100 hf457330 hf456100 hf457100 hf457470 hf455470 hf457220 vc740100 vc745000 hf456470 hf455560 hf455560 vr140800 v6607700 v7649200 v7649200 v7649200 v7649200 vg440200 vg440200 xo...
A b c d e f g h 1 2 3 4 5 f-20b f-20b f-20b overall circuit diagram note: see parts list for details of circuit board component parts. Trans former main 1/2 main 2/2 power on/off input aux in phones j, u, c s, bs 250v 315ma 250v t160ma l warning d2sba20 (vp344100) diode stack 1.5a 200v db1 gain sele...
