Yaesu FT-1000MP Mark V No RX-TX Troubleshoot & Repair Part-4 of 4 

Have fun, these radios can certainly be a handful.

@@M0XFXUK Hi John. Just as a note for future repairs, Yaesu UK still has stock of the original relays. Not cheap but keeps things OEM spec.

Hi Chris me too as I have come to the conclusion that these are not the best radios to work on. Thanks for the comment and I'm glad you found it interesting.

Thanks I am glad you enjoyed it.

Hi Bob I am chuffed that you are finding the videos helpful. My approach to making these videos is to try and cover what I wish someone would have gone through with me when I started out fixing radio equipment but that being said everyday is a learning day for me too. As you can imagine it's difficult for me to gauge how people are finding these videos so feedback is always welcome. Thank you I appreciate your comment.

The part about the company swapping good boards for bad.... i believe it, you ever seen certain techs on ebay selling faulty radios or even parted out radios ? makes you wonder why there's so many broken radios knocking about, strange though a couple of 'techs' have vanished though.

The FT-1000MP MKV is an attractive and feature rich radio and in my opinion a good performer however; they are as you say notoriously unreliable. A major problem is the front end of the receiver blowing diodes making the receiver deaf. I have done a little research and this seems to be by far the most common issue with these radios. I think there are a number of things at play here and most of which ultimately stem from a poor design. The radio suffers from a distinct lack of lightning and surge arrest devices in the front end which is odd as you would expect these radios to connect to large antennas, whilst lightning and surge arrest devices won't save the radio from a lightning strike they do offer a level of day to day protection against static discharge which is quite common and can easily damage the radio. Also the antenna socket A/B switchover relays always leave a path to the front end from the antenna even when the radio is switched off. Another problem is that the RX relay switching circuit is very poorly designed and leaves current on the relay coil when in TX condition, I think that this issue could well be up there for general reliability issues. If the RX Relay pulls in TX mode it will blow the front end of the receiver. The relay is boarding on pulling in when the radio is in TX mode and this only gets worse with ageing and hence why the radio starts making more and more trips to the repair house. The problem is primarily caused by the ageing of Q6450 (2SD667D) on the Tuner Main Unit which over time develops a creeping forward voltage across the collector and emitter this in turn moves the RX relay closer to it switch over voltage threshold. We are only talking about a few tens of millivolts of drop across the transistor but that is all it needs, again it's bad circuit design and the annoying thing is that with the addition of just few more components this stage would be much more reliable. The original design called for Q6450 to be a 2SA**** and it looks to me like Yaesu changed this to a 2SD667D for this very reason. In my opinion the whole Tuner Unit RF switching circuitry is a ticking time bomb and shame on Yaesu for releasing this. I really do feel that this is the problem most techs are overlooking when repairing this radio and I honestly think most techs are fixing effects and not addressing or being aware the cause. I have made a mod to this circuit which removes the RX relay current however; only time will tell if this holds up however; I am sure there is a better way to do this. As for repair bills, I guess this radio would certainly burn a hole in your pocket as they are very time consuming to work on. Regarding people swapping out boards I would say this has been going on since time and memorial with radio equipment as there sure are some unscrupulous people out there. Thank you for your comment I found it very interesting and good food for thought. I may just make another video going through the reliability issues with this radio once I've carried out some more research. Best Regards M0XFX

@@bigpimp347 Hi Mark Yep you've hit the nail on the head.

Thanks for the comment Alan. I am glad that you enjoy the repair videos.

Hi Chris thanks for the comment. LOL regarding the gloves they are a bit of a tradition with me and I guess it's a bit of a trademark. I tend to wear antistatic gloves when handling electronics not just for the antistatic effect it's more to do with leaving finger marks on PCB's. The grease dulls PCB's and over time erodes solder also I guess it is how I was trained when I was younger working on instrumentation and high frequency communication equipment PCB's. Not really necessary with what I'm doing in the videos but more of a habit I guess or OCD maybe?🤪 Re equipment thanks for the offer and yes I am running out of projects so if you want something sorting out please ping me an email and we can discuss it further. m0xfx.channel@gmail.com

Hi Alfio. I am unable to comment regarding the field version as I have never looked at one, however; they do share a lot of the same circuitry. There is an issue with MK5 MP which basically boils down to poor design of the RX/TX switching circuits in the Tuner Unit, which is a shame as the rest of the rig is pretty good. I made a mod using a diode, but if I am honest, I would not recommend this unless you really know what you are doing. I am thinking of making a follow-up video with a reliable modification and possibly a new PCB for the RX TX path switching, that's if I can find the time. The Yeasu FT-1000 MK5 is still a top performing rig and can more than compete with modern equivalent radios, that is of course they are running correctly. Also, radio's 20 years and over start to suffer from ageing, especially the electrolytic capacitors and tuning. It can become costly keeping these old girls going. That being said, they are a great rig to operate, I hope this is of help.

Hi Mark I don't think the RX issue was related to the MOLEX plug being in the wrong place on the PA board. I think that who ever was trying to carry out the repair could not manage to find the main fault and put the plug in the wrong place when reassembling the radio. This just made it harder for me to completely fix this radio. The main fault with this is poor design of the RF path switching on the tuner unit. It amazes me such a high end radio had such poor design. Yeah I did get lead up the garden path so to speak when a purchased this radio but it is what it is. I hope you are well mate.