TX Power








Spurious Oscillaton of PA

Problem: I have been in contact with another Ham over a problem that we both seemed to have. He is a FT1000MPMK5 owner, and I am the owner of a recently purchased second hand FT1000MPDC. We both have the problem that the PA takes off on 15 and 17mtrs with our station setups.

Solution: I have cured my problem by having a word with Yaesu UK, they sent me a modification kit comprising of 2 small toroidal coils and a strip of sticky back copper tape. The mod consisted of changing 2 air cored coils on the bandpass filter board with the toroids, and making sure that the PA compartment made good earth bond to the side of the rig chassis using the copper tape ( note, on my rig there was tape already in place but the corners were doubled over making the bonding worse ---- scratch off the corners and clean the bonding areas ! ). Also extra earth bonding of small screens on the PSU filter and bandpass filter boards by way of soldered 6mm earth braid. The paperwork for the mod appeared to originate in the USA, and was titled --- Antenna wont tune on 15mtr band. For anyone out there with similar problems I hope this proves of interest ! Yaesu UK said as an initial possible quick fix, try winding a 2 inch / 50mm diameter 6 turn coil in the coax lead to the antenna terminal on the rear ( external ) of the rig ---- alas this did not work for me ! Graeme G4CKH. graeme@g4ckh.fsnet.co.uk

Note: Had a similar problem with an older MP (Vintage 95). I did the braid and solder mod, moved the cable as recommended and did not do the toroids re-work. Did do the copper tape trick. All of the problems went away and have never had any problems since the mods. Ron - W4LDE




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