Many years ago, I did a modification to my FT1000D to reduce the internally generated diode noise as well as to reduce the radios' susceptibility to strong broadcast band mixing products. I have previously published the modification for the FT1000MP and have had a lot of positive feedback from that modification, so in response to a number of queries about whether the MP mod would work on the FT1000D, I have decided to publish my mod for the FT1000D and FT1000 as well. The replacement diodes that I have used are the HP 5082-3081 Pin Diodes. This type of PIN diode was carefully chosen and provides the best performance. I DO NOT recommend substitution of any other kind of PIN diode as the 5082-3081 provides the lowest distortion by a significant margin!!! The HP 5082-3081 can be obtained from Allied Electronics and Newark Electronics as well as several other companies.
The diodes are not cheap, but their improved performance more than justifies the cost!
The diodes on the RF unit to replace are:
Main Receiver BandPass Diodes:
D1007
D1008
D1009
D1010
D1011
D1012
D1013
D1014
D1015
D1016
D1017
D1018
D1019
D1020
D1021
D1022
D1023
D1024
D1025
D1026
D1027
D1028
D1029
D1030
D1031
D1032
D1033
D1034
D1035
D1036
D1037
D1038
D1039
D1040
D1041
D1042
Main Receiver Preamp Bypass:
D1044
D1047
Main Receiver Preamp Switching:
D1045
D1046
Sub Receiver BandPass (BPF1):
D9801
D9802
D9803
D9804
D9805
D9806
D9807
D9808
D9809
D9810
D9811
D9812
D9813
D9814
D9815
D9816
D9817
D9818
D9819
D9820
D9821
D9822
D9823
D9824
D9825
D9826
D9827
D9828
D9845
The theory of operation of this mod is discussed in my FT1000MP Receiver Noise Reduction.
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