@VK2AAF Icom AT-150 matic



5 thoughts on “@VK2AAF Icom AT-150 matic

  1. Dear friend, any chance of getting a high resolution copy of Icom AT-150 schematic as seen on your website? David Brown VK2DAR Hunters Hill Sydney.

    • When I got this AT-150, it would not tune. The motors are driven by +12V and -12V generated by a charge pump power supply which is contained in an RF shielding can. The -12V supply & its can were getting very hot. The reason for the hot -12V was the two driver transistors shown at the end of the red line. They deliver either +12 or -12 depending upon which way the motor has to spin. I replaced the two drivers. If this is the same problem your AT-150 has, do the same. You’ll find that the part numbers given (2SB562 and 2SD458) are for obsolete transistors. Use a cross reference to find modern equivalents.

      • I did that repair several years ago. As I revisit the schematic, you see the DC-DC converter on the right hand side. You can follow the -12V (-13.8V)line from the DC-DC charge pump converter to Q2, which is the -V driver for the motor MF2. Shorted Q2 was probably the cause but I replaced Q1 & Q2 because these are very cheap transistors, about $AUD0.30. So cheap that I think I had to buy a minimum quantity of 5.

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