Discussion in 'Radio Circuits, Repair & Performance' started by KJ4BJ, Sep 12, 2019.

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  1. KJ4BJ

    KJ4BJ Ham Member QRZ Page

    Need help. If anyone has any ideas, or better yet, knows exactly what the problem is, I am up for suggestions.


    Some time ago I was on 160 meters talking to some local hams. All was going well when I noticed my amp was only doing about 400 watts. I retuned my antenna. Flat SWR on antenna, amp, and radio. No fix. Then I checked the FT-1000D barefoot. The TX output power had dropped from 90-100 watts down to about 60 watts and could not do more. Turned up the DRIVE control to full meter deflection. No change. Later, after finishing on 160 meters, I started checking all the bands. On 80 meters, got 200 watts output but the DRIVE control would only deflect the meter to about 1/4 scale. Then from 40 meters through 10 meters, full 200 watts output and DRIVE control would deflect the meter to full. I thought it was just something in the 160 meter portion of the radio.


    Popped the covers and started looking around. Still had same readings as above into a 50 ohm dummy load. After weeks of looking, I decided to take the PA/PS units out and check the boards. As I was setting the assembly on the bench, a disc capacitor just fell out and landed on the table. I thought that was the problem. Replaced the cap with same value and reinstalled the assembly. Still no fix. But now the situation was worse. Now I had no TX output power at all on any band. Eventually per the service manual, I discovered I did not have the 31.5 VDC on the PA but did have the 13.5VDC. So I thought the PS board went out but could not determine which components were bad. Finally, decided to search for, and acquired another working PS board. After I installed it I now have the 31.5VDC and the 13.5VDC on the PA board after setting it per service manual. Still no TX output power on any band. I started thinking it was the driver and/or finals. Per service manual, I do not have any idling current on either the driver or the final, best I can tell. When in transmit, the rig's meter shows 31.5 VDC on the VCC scale and shows 2A on the IC scale. DRIVE control has no effect whatsoever and no TX output power on any band. I have even resoldered some possible cold solder joints to no avail. Everything else on the radio works fine. It receives like it was new. All the controls and buttons work as well as all the RX filters. Only thing the rig does not do is TX power. As of this writing I am going to connect a mic and see if I at least have audio output by listening to another rig.


    If anyone has any idea how to fix or troubleshoot, please let me know. Much appreciated. I am hoping the PA is ok and something else is the problem? If it IS the PA, well, I can pray I find a PA board. So far, it's like looking for a needle in a haystack. Thanks to all in advance for any assistance.

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