Hi James,

Welcome to the group! Before powering it on, I would first open it up and take a look inside. Members have been putting some hi-res pics in the Files section to help others.

The "Technical Supplement" in the files section (Files->"03 - Yaesu FT-980 All Manuals") has some good black and white pics. If you have any questions you can take pics and put in this group .... we can compare to our rigs and pics.?

While there are some common issues, the most problematic appear to be related to connectors (as you might suspect) and solder joints on the single-sided PCBs. If you don't see anything suspect (weird mods, blackened components, no "burnt" smell), you should be OK to power up. No variac or other precautions required.

The FT-980 architecture derived from the FT-One ... but Yaesu DID lower cost: the PCBs went from doubled-sided FR4 to Single-Sided CEM-3 type. The PCBs aren't card type. But the switches, buttons, encoders and knobs seem to be high quality. My unit was made in 1983 and has never had a front panel issue (I did have broken wire in a transformer once).

--
-Mat Breton, N8TW

I have just picked up a Rather Tatty and quite heavily abused Yaesu FT-980 that has not been cared for at all by the look of it, I will upload photos soon, but was after a little advice. The unit was once owned by one of the top BBC engineers of his time, and I’m sure it’s been heavily played with.

I know that when Yaesu released this radio it was in that period that I call “Yaesu’s Lost Years’”, yes they released some good radios, such as this model and the obvious FT-ONE, but I personally think that they hit a wall with regards to quality, if you look at the gear that went before even taking into account the FT-101 Series, they really did produce some very good kit, and say 5-10 years after the FT-980, they seem to start using quality parts again, but in between this and when the FT-980 and ONE were released switches and plastic bit seemed tacky and cheap, maybe it’s just me, but I was always steered away from restoring these models due to quality of parts.

Anyway, what I’m after here is some advise as to if there is anything that I should check before I apply power to the unit?

Are there any good restoration guides available for the FT-980?

Thanks in advance for any advice offered.

Kind Regards

James
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Got numbers 1 and 2 ready to go as soon as your filters arrive, Wald. The other things I need to do to these are to put a new battery backup harness in one and replace the FSK Unit in another. Seems it doesn't want to produce any output - the faulty unit joins a growing collection of modules destined for troubleshooting and repair in the "mule".

Those TCXOs look interesting, particularly in light of the fact they allow for external adjustment. One of my other favorite lines of gear is JRC. Their NRD-525 uses a 12.8MHz TCXO as its reference oscillator. A neat mod involves fitting an adjustable unit then making circuit changes which will allow the BFO control to tune it over a narrow range. (Normally, the control is only operative in CW mode.) This allows for "poor man's ECSS detection" - which is kinda funny as I lucked into a -525 with an Edvis PLAM board already installed.

I seem to recall a similar keyer design for the FT-90x...the several '980s and 901/902s I have which aren't equipped with keyers can benefit from the addition. Happen to have a source of these or a link to the design?

73 - Fred, N8YX

Progress on two of three, and insight to problems with the third.

I installed an AM and a narrow CW (250Hz B/W; 8.9MHz CF) filter in one of the queued-up '980s today and used that radio to test my repairs to the various PLL/VCO Units I have on hand. It still has some warm-up drift which I think will be cured with a master reference oscillator crystal swap. FWIW, Yaesu was still stocking these as of a few years ago (thanks Jose!) but I'm going to look into modifying one of my spare BFO Units to use a garden variety 30.0000MHz computer timebase crystal.

After the RX sections were working, I turned to Ye Olde Junque Box and retrieved one of what is probably the last unused Gen TX kits in existence. It went into the first of the rigs, though it looks like a TX parameter-set procedure is in order. Good power below 14MHz; not so much above. There's adjustments for that.? I had another Gen TX kit on what now appears to be a defunct RF Unit; it was bought for parts regardless and after I removed the kit the board was cycled back into the spares collection. That kit was put in radio #2, which also needs a bit of alignment. Part of this evening was spent setting IF stage gains and getting S meters to accurately track the generator output.

The deaf-as-a-post repair mule got a little more bench attention. It faintly hears a .01uV signal but the AGC doesn't appear to be very effective between On and Off, and I cannot adjust the S meter. Thoughts are that the AGC Detector/Amp section is wonky. Of course, this discovery was made after I bought another IF Unit from the action site...but spares are nice to have, I suppose.

That rig also suffer from the same tuning problem as another rig (still in line) does, and which I detailed in a thread earlier this year. I think what's going on is the MC14093B on the Dial Unit, which receives pulses from the photointerruptors and conditions them. CMOS of the period occasionally goes bad from "tin whiskers". I have another Dial Unit to swap into Radio #3 (due to come out of line when the ones I'm working on go back in service) and have a bunch on 14093Bs inbound too.

One of our members posted an ALC mod which shortens the response. I think both of the rigs currently on the bench sorely need it, based on observations of how the rig controls TX power. There appears to be a positive feedback loop in place due to the long action time - this causes a power rise. One more thing to investigate.

Have a few more mods up my sleeve once everything is up and running. Chief among these are auxiliary cooling fans.

73 - Fred, N8YX

These groups need a "Belay that..." button due to what happened next.

As soon as I hit "send" on my previous message I went to check on the rig, and the misbehavior which prompted me to replace TC01 was back. Hmmmph. Since I had a production line set up at my rework area I changed the trimmer on every loose PLL/VCO Unit I had and tried each in the rig - along with one from another radio in the repair queue. Apparently, the issue wasn't with that assembly - sounds like random noise modulating the VCO and eventually it drifts out of lock.

I swapped a spare BFO Unit in and that cured it. Question for Matt/Wald and whomever else has repaired this assembly: When the RF transformer went bad (open), what were the symptoms? I think this may be what's going on here.

A second rig in the queue appeared as deaf as a post. Its RF Unit was swapped into a working rig for test purposes and is fine. Next, the IF Unit was swapped...problem follows the board. That one's now headed into my "test mule" for additional troubleshooting. I've a couple things to do WRT RF Unit testing (evaluating a spare board) and installing filters but two of the rigs are coming along nicely.

Wants:

If anyone has a spare Inrad 2110.1 (2.4KHz B/W; 8.9875MHz center) filter or its Fox Tango/Seiwa equivalent, I'm interested in buying it.

Will post more as I solder.

73 - Fred, N8YX

For all who have repaired the VCO/PLL unit:

Did you replace the electrolytic capacitors when you had the unit out of the radio? I just replaced TC01 on the first of two boards and so far it seems to be working. Any value in swapping these out?

73 - Fred, N8YX

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One on the auction site at the moment, though a little more than you want to spend.

73 - Fred, N8YX

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Dave,

Not sure - going on some data from the FT-301 group. Randy, W7CPA managed to get ahold of the JA-release documentation for an FP-301D (w/ ID timer) and within was the layout for programming the PROM with your call sign.

Stands to reason that the FT-980 Aux Band PROM info may also be in limbo somewhere. If Chip knows of documentation and can release it for use, I'll be glad to work through the RF Unit end of things - including winding the various BPF coils. 60M is definitely on my Want list. When all is said and done with programming and RF setup I'm going to throw the converted '980 on my spectrum analyzer and verify it meets emission purity requirements.

On the old list (circa 2010) someone claimed to be in the process of reverse-engineering and re-writing the main PROM for the CPU. I've played around with 8085 programming and may very well attempt to do same, but the Aux Band Challenge needs completed first (too many projects in the queue...).

73 - Fred, N8YX

More assorted ramblings on the Aux Band ROM:

The device is listed as a TBP18SA030. Equivalent to an NS82123 and similar. These can be found on the auction site and via a few other sources...but the programmers may be a little harder to source.

When I was researching this project a while ago I ran across the following:



I bought a couple of them plus a programmer that supports the SST39SF010. If one leaves the Aux Rom socket empty, all the data lines should be set "High". Thus, to set a band segment one will have to program a "0" into the bit location. Per earlier comments, 5 bits should cover the entirety of the HF spectrum...leaving 3 bits for housekeeping stuff. I revisited the CPU Board this morning before typing out this reply and there doesn't appear to be anything special going on with the high (or low) bits of the band-data byte: All 8 are put on the bus and processed. Thus, any filter or VCO switching logic is probably done as a function of the CPU programming.

Those extra bits could be used to set the VFO (Ham or Gen) and for TX Inhibit. A bit of empiricism is going to come into play, one supposes. Given I can program the Flash ROM as many times as needed, I'm thinking of setting Bit 1 high, 2-5 low and 6 and 7 low...as a baseline. Then test and record. All 255 combinations could be tested sequentially and I just may do that to flesh out a data sheet completely.

There is still the matter of filter switching on the RF Unit (D70-D72) but I think I figured out what Yaesu did with regards to the control logic here. First things first: Getting the band segments recognized and the rig generating the correct LO/control signals.

73 - Fred, N8YX

Dave,

Best way to get extra coverage (IMHO) is for the group at large to reverse-engineer the Aux Band PROM programming, or to possibly get ahold of a JA-issue Technical Supplement (which - if like the FT-301 stuff - has service and mod information which never made its way into NA-distributed materials).

8 bits of data at each address; the chip connections allow for selection of 3 discrete addresses. Assume 6 of the data bits will be used to set the band edges (60 possible combinations) and that possibly leaves two for other (TBD) housekeeping functions. I have to study the interconnections again but I think all VCO and filter select data is controlled via that band segment data, rather than as a discrete nibble. Some RF Unit changes have to be made to enable the new "Amateur" Band Pass filters and the components themselves will have to be sourced. I've gotten very good at building these things...

Thoughts are to fit 5.0-5.5MHz (for 60M) and then work out the programming and coil data for 20-20.5, 26.0-26.5, 26.5-27.0, 27.0-27.5 and 27.5-28.0. That would hit all the popular transverter ranges. Proper selection of BPF and LPF is really the only way to go here and I don't see Yaesu's Gen TX mod offering anything in that regard unless the radio is operated above 22MHz. Even then I'd like to see a correctly tuned front-end circuit in play.

73 - Fred, N8YX

?

Hi Wald,

Would it be feasible to add a 6-dB or so amp just prior to the filter (I think most 6-pole xtal filters run about 9dB loss for CW ?)? That should compensate enough for the loss before the 3rd IF Amp.?

--
-Mat Breton, N8TW

Let me have a look at my filter stash and see if I have enough to filter all of mine up. If not I'll be in touch off-list. May also grab these for my FT-726Rs.

Thanks!

73 - Fred, N8YX

Which filters did you use, Wald?

I may be interested in them.

73 - Fred, N8YX