Modifications for the ICOM - RogerK

26-06-2001(IC-575) General Coverage TX ModificationAuthor: Adam MAURER, VK4CP - vk4cp@bigpond.com.MODIFICATION.NETAccess to the LOGIC UNIT is required.PREPARATION:1. Disconnect mains lead and antenna lead.2. Remove the EIGHT screws from the TOP COVER.3. Remove the FOUR side screws. (Two left & two right).4. Remove the top cover.5. Remove FOUR screws holding the PA/REG UNIT. (Two at top front & two at rear).6. Carefully hinge PA/REG UNIT back out of the way.7. Remove shield to LOGIC UNIT. (Unit on right hand side).MODIFICATION:Refer to diagram above.This modification is done to the LOGIC UNIT in three parts;1. Cut the red wire to J32. Add a diode (small signal type ie; 1N914 etc.) between PIN 18 of IC5 74HC244 [ANODE END OF DIODE] and the CATHODEof D10 [CATHODE END OF DIODE]. The back-up battery may have to be carefully levered out of the way in order to gainbetter access to PIN 18 of IC5.3. Add a diode (small signal type ie; 1N914 etc.) between the pad where D25 CATHODE would go [CATHODE END OF DIODE]and the pad just opposite D20 CATHODE [ANODE END OF DIODE]. See diagram for details. (that's coming later)Thanks to http://www.qsl.net/vk4cp/ for the modification.This modification is read 707 times.top of page