Heathkit
HW-104

[Rear Panel]   [Chassis Wiring]
[Improved Bypassing and Termination Checklist



[HELP! I just got a SB/HW-104.]

CQ, August 1975, pages 28-32, 68, 69, 73

[Functional Block Diagram]
[Receiver Block Diagram]  [Transmitter Block Diagram]
[HW-104 Large Full Page Schematic]

SlotBoard NameSB-104
(85-14xx-x)		HW-104
(85-16xx-x)		SB-104A
[A]Counter[85-1417-1]--------[85-1417-2]
[A]Calibrator--------[85-1636-x]--------
[B]Transmitter Audio
Regulator		85-1580-1[85-1634-x][85-1580-5]
[C]Transmitter IF[85-1420-x][85-1627-x]
[85-1929-2]		[85-1929-3]
[D]HFO
Premixer		[85-1418-1][85-1626-x][85-1418-4]
[E]Carrier Generator
Crystal Filters		[85-1581-2][85-1635-x][85-1581-6]
[F]Receiver IF
Audio		85-1462-1[85-1631-x][85-1462-6]
[G]RX Front End85-1459-1
85-1463-1
[85-1666-1]
85-1708-2		[85-1788-x][85-1931-1]
[H]Power Amplifier85-1422-1[85-1629-x][85-2055-1]
[J]Driver85-1421-2[85-1628-x][85-1421-5]
[K]ALC
Output Filters		[85-1425-1][85-1630-x][85-2056-1]
85-2187-1
[L]Noise Blanker<===== [85-1412-3] =====>
VFO Filter[85-1516-1][85-1633-2][85-1930-1]
VFO Oscillator
Buffer		85-1205-3
85-1206-1		[85-1624-2]
[85-1625-1]		85-1205-7
85-1206-3
  Later revision board should be used if available  
  Wiring to use Noise Blanker (L) may need to be installed  
  Chassis or board mod required to use SB-104A board in older radio