HITACHI 60CX29B
Manual de Servicio

General Soldering Guidelines 1. Use a grounded-tip, low-wattage soldering iron and appropriate tip size and shape that will maintain tip temperature within the range 500°F to 600°F. 2. Use an appropriate gauge of resin-core of 60 parts tin/40 parts lead. 3. Keep the soldering solder composed

Removal 1. Desolder and straighten each IC lead in one operation by gently prying up on the lead with the soldering iron tip as the solder melts.2. Draw away the melted solder with an anti-static suction-type solder removal device (or with solder braid) before removing the IC. Replacement 1. Carefully insert the replacement 2. Carefully bend each and solder it. 3. Clean the soldered (It is not necessary IC in the circuit board. the circuit foil pad

iron tip clean and well-tinned.

4. Thoroughly clean the surfaces to be soldered. Use a small wire-bristle (0.5 inch or 1.25 cm) brush with a metal handle. Do not use freon-propelled spray-on cleaners. 5. Use the following desoldering technique. a. Allow the soldering iron tip to temperature (500°F to 600°F). reach normal

IC lead against

areas with a small wire-bristle brush. to reapply acrylic coating to areas.)

b. Heat the component lead until the solder melts. Quickly draw away the melted solder with an anti-static, suction-type solder removal device or with solder braid. CAUTION: Work quickly to avoid overheating the circuit board printed foil. 6. Use the following soldering technique. a, Allow the soldering iron tip to temperature (500°F to 600°F). reach normal

�Small-signal� Discrete Transistor Removal/Replacement 1. Remove the defective transistor by clipping its leads as close as possible to the component body. 2. Bend into a �U� shape the end of each of three leads remaining on the circuit board. 3. Bend into a �U� shape the replacement 4. Connect to corresponding crimp the �U� metal contact, transistor leads.

replacement transistor leads to the leads extending from the circuit board and with long nose pliers to insure metal to then solder each connection.

b. First, hold the soldering iron tip and solder strand against the component lead until the solder melts. c. Quickly move the soldering iron tip to the junction of the component lead and the printed circuit foil, and hold it there only until the solder flows onto and around both the component lead and the foil. CAUTION: Work quickly to avoid overheating the circuit board printed foil or components. d. Closely inspect the solder area and remove any excess or splashed solder with a small wire-bristle brush.

Power Output Transistor Devices Removal/Replacements Heat and remove all solder from around the transistor leads. Remove the heatsink Carefully mounting screw (if so equipped). from the circuit board.

remove the transistor

Insert new transistor Solder each transistor
Y.

in circuit board. lead, and clip off excess lead.

Replace

heatsink.

Diode Removal/Replacement 1. Remove defective diode by clipping possible to diode body. 2. Bend the two remaining circuit board. leads

its leads as close as perpendicularly to the

3. Observing diode polarity, wrap each lead of the new diode around the corresponding lead on the circuit board.
Use Solding Iron to Pry Leads

4. Securely IC Removal/Replacement Some Hitachi unitized chassis circuit boards have slotted holes (oblong) through which the IC leads are inserted and then bent flat against the circuit foil. When holes are the slotted type, the following technique should be used to remove and replace the IC. When working with boards using the familiar round hole, use the standard technique as outlined in paragraphs 5 and 6 above.

crimp each connection

and solder it.

5. Inspect (on the circuit board copper side) the solder joints of the two �original leads�. If they are not shiny, reheat them and, if necessary, apply additional solder.