Yaesu FL-2100B/2277B Circuit Diagram

Power Input and Distribution

The unit accepts multiple AC input voltages: 220V, 117V, and 100V, each with associated switches (e.g., S3 POWER SWITCH) and input terminals (J1, J2). The diagram shows input selection mechanisms.

Two fans, FAN 1 and FAN 2, are present for cooling.

Power Supply Circuitry

A main transformer (T1) provides various AC voltages. A 13-volt secondary is isolated from chassis ground, necessary for a voltage doubler addition for increased cutoff bias.

The circuit includes a voltage doubler stage (DI IS1943, C224, C225) which changes cutoff bias from -18 volts to -36 volts. A modification note specifies adding a 130 ohm 5 watt resistor (R100) to correct relay and bias voltage after this addition.

Multiple rectifier diodes (D101-D110, D201, D202, D3) and filter capacitors (C101-C106, C200, C201-C209, C211-C226) are used to create stable DC voltages, including a +2.4KV supply.

A BIFILAR FILAMENT CHOKE (L2) is part of the filament circuit.

A V-METER (M2) and an I.C-SWR meter (M1) are included for monitoring.

Control and RF Section

The RF section features two tubes, V1 572B/T160L and V2 572B/T160L.

Various switches (S1, S2, S4, S5, S6, S7) control different operational modes and safety features (S7 S. SAFETY LOCK).

Potentiometers VR1 and VR2 are used for ALC (Automatic Level Control) adjustment, with VR1 being the main control and VR2 allowing a wider range of adjustment.

VR3 100K is the SWR SET CONTROL.

RF input (J4 RF IN) and output (J3 RF OUT) connectors are provided.

Multiple inductors (L201-L209) and capacitors are used in the RF path.

A relay (RL1) is present, likely for switching or protection.

Notes and Specifications

Notes:

• All resistors are in OHM, 1/2W ±10% unless otherwise noted.
• All capacitors are in F (Farads) unless otherwise noted.
• 'Value is nominal'.

Modification Notes:

• A modification for the SK-201 interface by Harbach Electronics involves changing R1 to a 22K ohm resistor to work with -36 volt key voltage.
• Added voltage doubler to change cutoff bias from -18 volts to -36 volts. A resistor (R101) must be added between bias set resistor (R4) and relay to correct voltage across relay and bias voltage. 13 volt secondary from transformer and lamp grounds must be isolated from chassis.
• Added 130 ohm 5 watt resistor (R100) to correct relay and bias voltage after voltage doubler addition. Cutoff bias voltage changed from -18 volts to -36 volts.

Key Components

This section summarizes key components identified in the diagram. For precise values and types, refer to the diagram itself.

Tubes:

• V1: 572B/T160L
• V2: 572B/T160L

Transformers:

• T1: Main Power Transformer

Chokes:

• L2: BIFILAR FILAMENT CHOKE
• L201-L209: Various inductors

Diodes:

• D1: IS1943
• D101-D110: 10D10
• D201: IS1007
• D202: IS1943
• D3: IS1007

Switches:

• S1, S2, S4, S5, S6, S7 (S. SAFETY LOCK)
• S3: POWER SWITCH

Potentiometers:

• VR1: Variable ALC control
• VR2
• VR3: 100K SWR SET CONTROL

Connectors:

• J1, J2: Power Input/Selection
• J3: RF OUT
• J4: RF IN
• J5

Meters:

• M1: I.C-SWR
• M2: V-METER

Capacitors:

• C1, C2: 0.01u
• C7: 0.01u
• C8, C9: 0.01u
• C101-C106: 100u 500WV
• C201-C202: 200P
• C204: 50P
• C205, C225: 0.01u
• C206, C207: 0.01u
• C210: 0.01u
• C211-C212: 200P
• C213: 350P
• C214: 500P
• C215: 100P
• C216: 200P
• C217: 250P
• C218: 400P
• C219: 1000P
• C220: 1000P
• C221: 1000P 3KV
• C222: 1000P 3KV
• C223: 500P 3KV
• C224: 1000P 3KV
• C226: 3000 3KV

Resistors:

• R1: 220K 2W
• R2: 2.2K
• R3 SHANT
• R4: 30 10W
• R5: 1.5M 5%
• R100: 130 5W
• R101: 100K
• R102: 22K
• R101-R110: 470K
• R111-R115: 220K 2W
• R201, R202: 33 1W
• R204: 4.7K
• R205, R206: 22 2W
• R207: 47K 2W
• R208: 22W
• R209: 3.3K 1W