Communication-concepts EB63A Construction Hints Bedienungsanleitung PDF herunterladen

CONSTRUCTION HINTS FOR THE EB63A

These construction hints for the EB63A are only to supplement the Engineering Bulletin

and are not meant to be used as a construction manual. Due to parts becoming

obsolete or hard to find, some changes are recommended for the EB63. The 1N4997

bias diode is no longer available and a recommended substitute is the MJE243 transistor

used as a diode. The relay has become very hard to find and if found is very expensive.

An Omron replacement relay is recommended and the board has been modified to

accommodate this relay. Also the original COR circuit did not perform very well as

board.

HEATSINK PREPARATION

A heatsink of sufficient size to dissipate over 140 watts of power should be used. The

heatsink should be marked, drilled, and tapped before construction begins on the PC

board. Using the bare PC board as a pattern or template, lay the PC board on the

heatsink in the desire position and mark the four mounting holes. Do not mark or drill a

hole for D2. Typically, placing a metal bolt through the mounting hole of the diode D2

will short out the bias supply to the heatsink. Drill and tap the four mounting holes for 4-

40 screws. After the four mounting holes are drilled and tapped, mount the bare PC

board flush on the heatsink using 4 – 40 x ¼” or 3/8 “ screws. Place the RF transistors

through the PC board so they rest flat on the heat sink. Mark the mounting holes for the

RF transistors. Remove the RF transistors and PC board from the heatsink. Drill and

tap the mounting holes for the RF transistors (4 – 40 screws). The heatsink can also be

fitted with connectors, cover, etc. at this time if so desired.

BROADBAND TRANSFORMERS

Just a quick word about the broadband transformers. The low impedance winding of the

input (T1) and output (T2) transformers consists of a one-turn winding. Two tubes form

the low impedance winding. The tubes are electrically shorted on one end by a piece of

copper-clad laminate (PC board) with holes for the tubes. The tube ends are soldered to

the copper foil. A similar piece of laminate is soldered to the opposite ends of the tubes

and the copper foil is divided into two sections, thus isolating the ends where the primary

connections are made. The high impedance winding is formed by threading Teflon

insulated wire through the tubes for the required number of turns. The transformers are

loaded with ferrite material to provide sufficient low frequency response.

PC BOARD ASSEMBLY

Install the ¼ watt metal film or carbon resistors R2, R3, and R7 in their proper locations

(refer to the placement layout in the construction) and solder in place. Clip the leads

close to the PC board. R1 is not used.

Install the 1N4148 diodes D3 and D4 as shown. Observe the polarity..!! The banded

end is the cathode.

Install transistors Q1 and Q2 as shown in the component layout. The flat sides of the

transistors face the outside of the PC board.

1 2 3 4 5 6 7 8 9

Inhaltsverzeichnis

Seite 1

CONSTRUCTION HINTS FOR THE EB63A These construction hints for the EB63A are only to supplement the Engineering Bulletin and are not meant to be used

Seite 2

Install the 1N4001 diode D1 as shown. Observe the polarity..!! The banded end is the cathode. Position the transformer T2 on the PC board as shown

Seite 3

Install the 0.1 ceramic mono capacitor C4 on top of the PC board as shown in the component layout. Install the 470 uF electrolytic capacitor C22 (obs

Seite 4

Install the 330pF mica capacitors, C8 and C9, on top of the PC board as shown. The capacitors should stand approximately ¼” above the PC board. Thi

Seite 5

relay will drop out. Also the relay may drop in and out during SSB operation if the relay hold delay is not long enough. 2. Relay locks up – this c

Seite 6 - EB63A PARTS LIST

Figure 2 - EB63A COMPONENT LAYOUT EB63A PARTS LIST C1 33 pF Dipped Mica R1 Not Used C2 18 pF Dipped Mica R2 47K ohm ¼ W Resistor C3 0.1

Seite 7 - EB-63 COMPONENT LAYOUT

Q2R3Q1C3D3 D4 R2 R7 C11C12C1K1D1OUTPUTINPUTR6T1C10T2C20C8Q4 C9C4R4 Q3 RFC1 C6 C7C5R5C2 C21 C22Q2R3Q1C3D3 D4 R2 R7 C11C12C1K1D1OUTPUTINPUTR6T1C10T2C20C

Seite 8

D2 is mounted flush on the bottom of the pcb with the metal portion of the transistor/diode against the heatsink D2D28

Seite 9

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Communication-concepts EB63A Construction Hints Bedienungsanleitung

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