Icom IC-775DSP internal antenna tuner replacement.
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- Опубликовано: 6 сен 2024
- While I wait for my replacement parts from China I decided to replace the entire antenna tuner assembly. After replacement you need to follow the internal tuner reset procedure to get things working correctly.
Glad to see you got it fixed! Hope the new chips workout! Nice station you have...wouldn't mind seeing the antenna farm! :) 73's OM. ~Jack, VEG
I originally bought one new back in November of 1999, had it for almost 10 years and reluctantly sold it to get something else. Acquired both of these off eBay, aside from the issue I had with one of them they are solid performers. I plan on getting around with an antenna video but the snow has arrived. I just received a new Hygain AV-640 40 through 6 meter vertical. 73 Jack and thanks for watching.
Having issues with atu also found 1 motor not working and plastic shaft connector with grub screws has a crack got parts coming but the receiver sounds deaf now would that be the case if the atu isnt tuning ?
I would say that is likely. I notice on my 775's the receive is muted and the sensitivity comes up as the tuner reaches the point of match. I find this preferable since the tuner acts like a bandpass filter to help attenuate strong out of band signals.
That's brilliant. My old icom 775dsp died, but I loved that rig and have been trying to get another one for ages, but trying to find one that works and in good working order over here is just about impossible.
73 zl3xdj.
I hear ya, these transceivers make an appearance on eBay from time to time but some have seen some pretty rough service. Others are simply unloading them because Icom no longer services them and getting parts can be difficult. But, every once and a while you can find one that the owner has kept serviced.
I also have an issue with my at in the 775dsp.
With certain amounts of outputpower it tunes.
After crank up the power a bit it drops seeking again.
Think it needs a reset as well.
Seems it is an alignment thing?
If it interests you i can post the result,doing the reset soon.
Rob de PE1RYX
Hi, can it just be that the original tuner also needs the reset? And has no hardware issue??Rob de PE1RYX
Greeting Rob, I reset this tuner twice and had the same results both times. It would complete the procedure without errors but still wouldn't tune 15 or 10 meters. With a bit of troubleshooting I discovered that the fault was being caused by a defective relay driver, however also discovered that it was the relay driver for the inductance selection relays. I originally suspected the capacitance section but this wasn't the case. Thanks for watching! 73
hey craig leigh VK7 WUU in Tasmania Island just wondering what the chip set cost you from china as in the cost of the chip set and freight as I'm just about to purchase long overdue ic 77s DSP and it have and intermittent tuner issue ??? may be connector or just a reset may fix issue as it still does tune on second attempt so could be the beginning of the chip set issue OR perhaps the reset of the tuner re setting ( memoriesing ) all the values of flat match on all bands fingers crossed may correct issue if I'm lucky , either way id like to obtain a chip set to future proof myself from that issue ?? did it fix the tuner unit you took out of the second 775dsp ?? and can you notify me of any other common issues re this icom model please cheers 73's VK7WUU LEIGH SOUTHERN TASMANIA ISLAND AUSTRALIA ...
Good Morning, at the time I purchased these I paid a total of $27.48 for 5 units including shipping. In my case the outputs that close the inductor relays on 15 and 10 meters were not engaging. I even sent 5 volts to the inputs on the IC and all the relays closed except 15 and 10 meters. An identical IC is used to select capacitor values and it worked fine. I still have this tuner on the shelf, it hasn't been a high priority for repair since I had another fully functional tuner and simply swapped it out. When conducting the tuner reset procedure use a high quality RF load, avoid the typical loads like "cantennas" or other cheap RF loads. I used a Motorola model T1013A RF load. Also use an oscilloscope set for DC coupling and limit the bandwidth to 20MHz or less, you can then adjust the trimmer for minimum voltage. So far this is just one of the issues I have come across with these tuners. The other issue is where the tuner cannot match the antenna due to the mismatch being out of the tuners range, or the tuner will only tune part of a given band. This is usually fixed after readjusting the reference voltage and forcing a re-learn, if not there may be something wrong with the antenna or the feedline. 73 and thanks for watching!
@@CraigPetersen12f36b
thx craig , thought id finally score a unit but the owner was an elderly man whom's eyesight as far as condition of the unit was far from expectations once photos were received lol so still looking for an amaculate unit in Australia as still after cover freight pretty much kills anything out side Australia cheers leigh vk7wuu
No problem Leigh, I originally purchased an IC-775DSP back in November 1999 used it for about 8 years or so and sold it. The two units I have now were purchased off of eBay about a month apart. The first unit I received is in very nice condition and came with the CR-282 high stability reference installed. I was able to find all the optional filters off of eBay as well and now have a fully optioned unit. The second unit has a few more wear and scuff marks, this unit was modified for 60 meters and has the UT-66 voice module installed, this also is the unit that had the tuner issue. It is possible to find good working IC-775DSP transceivers, it just may take awhile to find one, these units were manufactured all the way to 2003 so you should be able to find a clean unit. 73..