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IC-476 and PRO LCD backlight repair mod [message #1484] Thu, 06 September 2012 02:07
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IC-746 Backlight Repair / IC-746PRO Backlight Repair

Here is how I mounted a TO-220 type transistor in place of the original backlight driver transistor, Q302. An ECG/NTE 378 in the TO-220 case style will substitute for the surface mount 2SB1201 that came with the IC-746.
You will need to unsolder and remove the shield, drill a hole in the case and mount the new transistor.

This provides a larger heatsink and a transistor with more thermal dissipation ability. You will need to isolate the transistor from the shield using the insulating kit that comes with the transistor. Be sure and use thermal heatsink silicone grease.

After mounting the transistor, solder the shield back into place.

You will need to run small jumper leads soldered to the NTE-378 and run over to the pads on the PC board where Q302 was lohoneyed. Looking down from the top where Q302 was lohoneyed, the lead configuration is Base Collector Emitter from left to right. The Base pad is close to the shield, and the Emitter pad connects to L301. Collector goes to the center pad.

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E. Kirk Ellis, KI4RK

[Updated on: Thu, 06 September 2012 02:07]

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