Problem: Tuner does Not Tune-Up Properly


UPDATE: Download Yaesu Service Bulletin
Bulletin TSN-9606-A (Page 1)
Bulletin TSN-9606-A (Page 2)
Bulletin TSN-9606-A (Page 3)

I was using the antenna tuner on 15m and noticed that the tuner did not tune anymore. Actually when I press tuner- button, the "tuner" and the "wait" light was on, hen I press tune-button and nothing happened except SWR in the mp-meter was 3.0:1, but it did not tune at all. I check other bands 40-10m, where I have antennas and all has the same thing, swr was even more than on 15m and tuner did not work at all. So I took power down from the front panel, I took power down from the separate power supply and wait, thinking at the same, that what the heck I made wrong. After a while, less than a minute, I heard tiny "klik... klik" sound, maybe two of them. I decided to put power back on and everything seemed to be normal again, it does tune on every band properly. So I do not know what happened, but time made the trick this time. I did not "reset", nor "boot" my mp. I wonder, what was it? Normal? or just maybe overheating. Does someone else had the same problem? I remember tuner troubles written before here on reflector, was mine the same thing and does it have a cure, or should it be cured?  OH2BV

I have experienced two inexplicable incidents recently in which after I switched bands, the SWR maxed out with or without the tuner in line. The only way I have been able to correct the high SWR condition is to turn the power off and then on. This is the first time I have observed this behavior in three years. Joe


It's because you exceeded the 39 memory channels allocated to the antenna tuner. There has been much said about this. Search through the archives, there is a ton of information on this subject. John Winward, K3AOT

Press SUB/CE and ENT together while powering up. The will reset the tuner memories (and all other memories). It will not reset the menu settings. You do not have to run TUNE for the antenna tuner every time you change bands. It remembers tuner settings 39 times. It is suggested that you use TUNE only two times for each band -- once for the low end (CW) and once for the high end (SSB). The tuner does a good job of tracking between these two memorized settings. If you do this, you will never fill up the 39 tuner memories again. Earl K6SE

Hit the tune button 39 times and your tuner memories are full. Think of these "tune button" settings as dots on the curve. The MP will fill in between the dots using a straight-line extrapolation method. When you are tuning around with the tuner on, you will sometimes see the little "wait" light come on. That's the tuner extrapolating.
I cover 40 meters with 4, 80 with 7, 160 with 5, 10 with 5, the other bands with 3. the three points are low swr point, 2/3 of way from there to high end, and 2/3 of way from there to low end. The one in the middle might not need tuning per se (it could be 1:1), but it tells the tuner where the swr curve reverses direction and to start extrapolating with the "dot" for the other end of the band.

Tnx, John. However, I recently reset the tuner memories. Maybe I may have already again exceeded the 39 limit, since I use the rig both barefoot and with an amp and frequently hit the tune button. I'll have to check. On the other hand, this problem seems to occur somewhat somewhat unpredictably and inconsistently. If it were the memory issue, I would think it would occur every time I changed bands or hit the tune button. Joe

As far as my problem was concerned, I called Yaesu UK and they sent me out the modification free of charge and it arrived next day. I removed two inductors from the RF unit and replaced them with the supplied toroidal types and also fitted some copper tape to improve earth bonding. On reassembly the rig worked first time without any further problems.

Now, it has been pointed out to me by other members on the 1000mp reflector that you may be interested in placing a 'clean' copy of the scans for this mod on your website. M0JWB Portishead. UK




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