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Mat (and all),

I'm going to order the prototype plate (along with some motorcycle radio project pieces I need) in the next few weeks, then when I finish machine work on a couple of the parts I'll ship everything off to the powder coaters.

There is another plate I'm going to fabricate for this effort, and I may do a CAD pattern for that one too. If you look next to the AC connector on the back of the radio you'll see a punched (but taped) hole; the plan is to use this space to mount a plate that will hold a coaxial DC power jack and an RCA connector for feeding the 8.9875MHz IF out to a YO-901. Plan is to borrow the method Yaesu used with the FT-90x, as this area of the IF strip is identical in both designs.

The other mod I'm going to perform to these rigs is the cascade filter board installation (though I'm going to have to homebrew at least two of the boards). My test rig will be going back on the bench as soon as I finish restoring a couple of FT-902DMs and I'm going to see about decoding the mystery of the Aux Band PROM. FWIW, I did some testing of the Gen TX Mod and from 22MHz up it seems to provide power on par with the Ham VFO/BPF arrangement. For 60M use...no. There's got to be a better way to approach this addition with a '980, and I'll attempt to solve the puzzle.

73 - Fred, N8YX

If you can send a pic of the finished job I'm interested.?

I put a picture of my version of the mod in the files section a while back:?/g/Yaesu-FT-980/files/06%20-%20Mods/Adding%20a%20super-quiet%20always-on%20secondary%20cooling%20fan.pdf?I used an 80mm computer fan right in back of the original. The key was getting a "super silent" on, rated at only 26dBA at full power, while still? moving up to 32cfm.

--
-Mat Breton, N8TW

Hi Fred and Matt,?

All,

I'd indicated in a repair/mod thread last week that I was going to design a mounting plate for an auxiliary cooling fan setup. After a lot of studying and contemplation this afternoon I decided to re-design the entire rear panel for mounting two additional 60mm computer fans over the PSU area. The original PA heat sink fan opening has been given a different look as well.

Original panel mounting hole locations were used. The new panel won't quite be "plug and play" owing to the fact that the holes for the fan screws and 4 of 6 plate mounting holes (center and rightmost two, looking at the rear of the radio) must be countersunk in order for things to fit nice and flush. Plan is to use M4 flat head screws for the fan mounts; these will be captively retained by thin M4 nuts and the fans will slide onto them. I managed to locate a gasket/spacer for a 60mm fan which should allow proper sealing and spacing over the captive nuts. I -may- get lucky and not have to countersink the 4 plate mounting screws with this arrangement but at least there are fall-back options.

This evening I sat down at the CAD terminal and whipped out a design, then played around with the various online laser cutters to see what kind of prices they'd charge. SendCutSend came in at around $20 for single-quantity 1/8" 6061-T6, with the next available lot size at 5pcs. You'll need to finish the panel after machining is complete; I'd recommend powder coating if you have a shop nearby. You'll also need to source slightly longer mounting screws for the plate.

If there's any interest in this effort, I'll upload the DXF to the Files area. I'll get a sample part cut then spec the rest of the hardware and post a list of sources along with an assembly guide.

73 - Fred, N8YX

It's a long shot, I know... but does anyone on the list have one or more of these they want to part with? This is the unit which Inrad marketed for the FT-920.

I'd like to fit three of my four '980s with the boards; I have the required filters. The other radio will stay "wide" for FT8 use.

Also looking for an XF-8.9GA, or the Inrad/Seiwa/Fox Tango equivalent 6KHz B/W filter.

Thanks - 73

Fred, N8YX

(Splitting out from the "File uploaded..." header)

"One thing I found in all the FT-980's I found (5) is the S meter is very scotch.? I hate giving a strong signal that only reaches S5 or 6 when I get a 5/9.? So raise t5he S meter slightly.? I have an older IC-740 I use that is too generous as a standard and usually split the difference."

Dave and all,

Agreed WRT S-meter. This is a function of meter amp circuit linearity and could probably be addressed by a re-design of said circuit. I spent a bit of time at the bench over Christmas break with 3 of 4 FT-980s and a service monitor w/ calibrated RF generator. Best I can do with the three is S-8 indicated @ 50uV applied, S-9 @ 100uV applied and 40/S-9 @ 10,000uV applied; this at 14MHz. A/B tests with my TS-930S on the same antenna show the '980 tracks within an S unit everywhere; usually they're right on the mark at anything above S-8. FWIW, I can turn the generator to its lowest setting (< .01uV) and the FT-980s still hear it.

Another "challenging" S meter setup lies within the NRD-515. Above S-7, those meter circuits and meters track EXACTLY for a 6 or 10dB increase or reduction in applied signal; below that it's Forrest Gump's box of chocolates. Rob Sherwood and I have gone back and forth about the subject at length, and some of that discussion may make its way onto a JRC reflector at some point.

In regards to:

"Chip K7JA told me at Dayton in 1994 that the 980 had the best receiver of any Yaesu.? You just had to ignore the phase noise which I never found a problem.

73 Dave K4JRB"

I played around with my 40/75M '980 last night for a bit on the low end of 40. Lots of CW out and about to allow one test the various filtering functions. There was someone whose keyer was stuck on "dah", either intentionally or not. Less than 100Hz away was an S-4 DX signal. 600Hz filter engaged, notch on the offender, APF used to peak the desired signal. I heard an absolutely pure, perfectly readable tone with no hints of interference or modulation from the nearby neighbor - or from anyone or anything else on the band for that matter. Granted, on SSB these rigs could probably benefit from a cascaded filter arrangement (as some of my others employ) but they're great on CW and FSK in terms of interference suppression.

A question for the group at large: Does anyone notice "phase noise" with these rigs, and if so under what conditions?

73 - Fred, N8YX

My 40/75M FT-980 now has the 3-cell backup unit in place. That mod looks interesting, Matt. Next time any of them have to be disassembled to the point of CPU access (which I hope is never!) I'll perform the mod.

Part of my holiday ritual (both Christmas and 4th of July week) is to replace any AA backup batteries in the various gear that uses them with freshly-charged cells then throw the extracted ones on the charger for use elsewhere. Right now, two active FT-980s and an FV-102. An FV-101DM and several JRC NDH-51x memory units will be joining that collection, though I'm tempted to mod the JRC gear to use a 1F, 6v supercap in place of the batteries (which are a known major PITA in those units).

73 - Fred, N8YX

I concur: 4.5V looks to be OK ... especially since the?

Note: the root cause of the relatively short battery life is extra leakage though R09 (>100uA). There is a simple mod in the Files section (?/g/Yaesu-FT-980/files/06%20-%20Mods/Article_%20Extend%20backup%20memory%20life%20to%2010%20years%20on%20FT-980.pdf?) that REALLY extends the life. Although I haven't tried the mod myself, the mod makes sense ... you basically add a transistor that will switch off the leakage path when the uC is "off".


--
-Mat Breton, N8TW

In a recent shipment of parts, I got the memory battery trap door from an FT-980. On it was attached a 3-cell "AA" holder.

The OEM unit was a 2-cell (3v). Looking at the CPU Unit's RAM (uPD445LC) device specs, I see a max VCC of 7.0v. There are blocking diodes in series with both the 5v supply to the chip and from the battery bank to it, so the max applied voltage looks to be around 4.5v...and around 3.9v when the battery backup is supplying power. Well within safety limits.

Consensus on switching to a 3-cell arrangement? If will definitely give longer backup life.

73 - Fred, N8YX

All,

The LEDs are 1x5mm rectangular. NTE3160 (red) and NTE3161 (green) are commonly available and I see a few eBay sellers with other branded LEDs in the same form factor. Pretty sure Rohm and Liteon made these at some point.

Yaesu used the same type LEDs for the FT-707's S meter, in a green-yellow-red arrangement. These can be cannibalized if all else fails...as can the numerous models of CB radio and car audio equipment which also employed them.

When swapping the LEDs, remove the Attenuator shaft from its coupler (and from the radio). Unscrew the top-most two screws which retain the front panel and tip it downwards onto your bench. I put bubble wrap under the radio and on the bench as a cushion. Work on the Display Board LEDs first - all three boards come out sequentially. A good temperature-controlled vacuum solder sucker (Pace, Metcal, Weller, what have you) is essential for the removal of these LEDs. The holes in the board are somewhat of a tight fit for the leads even without solder. It may take a few sessions with the desoldering tool at each LED for remove them, working each out bit by bit until free. Afterwards I apply some solder to the now-vacant holes and use the desoldering iron to completely clean them.

Insert the new LEDs, carefully replace the front-most Display Board as you guide all the LEDs into their respective front-panel holes. You want to ensure the board is seated correctly before positioning the "loose" LEDs you changed out. When all looks good, solder and cut the leads flush then reinstall the middle and rear Display boards. The Keypad Board LEDs are MUCH less fiddly in terms of removal and installation. Trickiest thing here is to make sure the keys and foam inserts stay in the front panel when you lift the Keypad Board and that all the keys work properly when it's re-installed. There are three wires which must be desoldered from the board as the LEDs are being removed: Yellow (RXC LED), Green (TXC LED) and purple (Ham VFO LED). It goes without saying that if you elect to change other LEDs these instructions are partially accurate...but this should give one a good idea about what to expect. I also remove the Memory Switch and FWD Set potentiometer from the front panel prior to removal of the Keypad Board.

The same caveats hold true for positioning the Keypad Board LEDs as the Display Board's parts: Ensure correct position of ALL LEDs (including the OEM ones) before you solder; the freshly installed parts can be moved in or out as needed prior to application of the iron. Re-solder the three wires you removed then attach the insulator/hold-down plate which covers the RX/TX Clarifier LED area of the board. Remember the solder lug which grounds a small capacitor from the Memory switch. Replace the Memory Switch and FWD Set pot along with their knobs.

In my new color scheme, Green is Good. The Ham VFO and VFO Control indicators are both green, so at a glance if this is what you see you're good to operate without worries. I changed the RX and TX Clarifier LEDs to red, as well as the Split and Remote (CAT) LEDs. The Gen VFO was left yellow as were the others. If the operator sees red in the status window and yellow in the VFO indicator area, it behooves him or her to pay attention to which VFO is selected for TX and which other operating parameters are in play so as not to damage the rig.

I'll touch briefly on the "Gen TX Mod" (Yaesu kit) in a separate posting.

73 - Fred, N8YX

Mat,

What type of LED did you use?

Has anyone replaced the meter backlighting bulbs? Drake uses a blue (filtered bulb). I was thinking something like a "cool blue", or "light green" LED might make things "pop" and provide better coverage. For those ex-mil, maybe tactical red?

--
-Mat Breton, N8TW

One thing I've noticed is that there are two different CPU Units used in these rigs. They aren't readily interchangeable given the location of one of the connectors on the rear of the unit. The wiring harness in an older version is about 1/2" too short for the mating connector to plug onto its CPU Unit complement.

An FYI for those with a flaky CPU Unit. The newer one uses right-angle headers mounted on the vertical walls of the unit enclosure, while the older version used straight headers and a slightly larger PCB. An older CPU Unit SHOULD work in a newer radio, but double-check the identity of all connectors on the back of the unit

73 - Fred, N8YX

Happiness is 3 working '980s and a 4th well on the way (test-bench mules are never done).

Got an FSK Unit in the mail, swapped into the radio w/ no FSK output...and full output. Aligned the transmitter sections of #1 and #2, put the covers on and pulled #3 (my FT8/PSK rig) out of line for troubleshooting. It had a wonky tuning problem wherein after it warmed up the dial wouldn't move the frequency (as I noted earlier in thread). A spare Dial Unit fixed it and I now have MC14093Bs for the defective one. This rig also had a transmitter/receiver alignment performed.

I get ~105w out on 160-30, 120 on 20, 140 on 17-12 and 100 on 10. This is uniform across all three radios and far below the max rating of the PA transistors. Full power is achieved at the 9 o'clock setting of the Drive control. I may tack a resistor across the "mule's" Drive pot when I get that one on the air and see if the spread can be made more linear, a la the FT-90x's Carrier control mod.

While I had the radios apart I changed some of the indicator LEDs, using different colors. Yaesu loved yellow for these; Kenwood, red. I like to see status-at-a-glance and chose mine based on operating parameters and warning level. A pic of the result is in the Files area. Should anyone want more details I'll create a separate thread on the mod.

Also got Wald's XF-455MC filters installed in two of the rigs. These have narrow(er) filters at 8.9MHz, so I swapped the CW-W and CW-N lines of J01 on the IF Unit. Dave ('JRB) pointed out that the Yaesu Gang recommended using the 455KHz/600Hz B/W filter in combination with the APF function. My observations are that it'll work well for everything but the most demanding contest operation, so it's nice to have both options.

Next project...I'm weighing two options for the auxiliary cooling fan arrangement. One is a mounting bracket made from aluminum angle; the other is a flat plate w/ cutouts for air flow. If I go with the latter I'll design a plate on my CAD terminal then post the DXF file into our Mods area. Members who want them can go to one of the online laser-cutting outfits and submit the file. FWIW, I'm going to use a pair of 70mm 24v computer fans so the mounting holes will be dimension-ed accordingly.

73 - Fred, N8YX

The following photos have been uploaded to the Indicator LED mods album of the [email protected] group.

• 20211227_180026.jpg

By: Fred_N8YX <N8YX@...>

Thanks Mat for the pointers, will check to see what it is like under the panels and will post some photos, no rush on this one, but would like to have her running for just the beauty that she is.

James
www.Md0mdi.im

On Thu, Dec 23, 2021 at 11:20 AM, Wald N4PL wrote:

I also thought of the TXCO solutions. It looks like Seiko has an interesting part in the pipeline, available next year from Mouser:

Hi Wald,

I've also considered installing a TXCO. I actually had to change the pulling trim capacitor (larger value) in the existing circuit to extend the adjustment range ... it has drifted beyond what the original trimmer could compensate for.

I think the "poor man's" xtal heater in these rigs is tough on the xtals (worse than normal aging drift). And even with the heater working properly there is still some amount of drift as the fan turns on/off, room temperature changes, etc.

One thought I've had is the effect a CMOS square wave or clipped sine wave might have if not filtered. The tank circuit on T11 (VFO board) does a great job of cleaning up the existing oscillator ... so maybe we could inject the signal ahead of that stage? The output of T11 is supposed to be around 1.5Vp-p (nominal) I believe.
?
--
-Mat Breton, N8TW

Hi Fred!

"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."

I was very lucky in two respects:
1. The transformer that went bad was the BFO mixer, and therefore easy to locate. This transformer is actually in the first stage of the AF board.
2. I was able to repair the transformer (vs trying to reverse engineer and fine a similar one)

1. The symptoms for mine were obvious: I had great audio for FM, AM-N, AM-W ... and no audio for RTTY, CW-N, CW-W, USB, LSB (even with strong RX signals injectected). A look at the signal flow in the Technical Supplment guide showed that the common circuits would be either the BFO, or the BFO Mixer. After verifying the BFO was working, I was left with the mixer circuit.

2. Inside the transformer, one wire had broken off right where it was soldered to a pin. While the wire was too short to directly connect, I was able to "extend" the pin with a piece of thicker wire, and then attach the broken wire to that.

On the downside, the broken wire was intermittent, and it took me several attempts to track it down. Just rotating the rig would sometimes make it work/non-work. Temperature would cause it to occur or "fix itself". Pushing on the AF PCB in different spots would do things, misleading me to thinking it was a solder joint or trace issue.

But ... once found and fixed the rig has performed flawlessly since.

--
-Mat Breton, N8TW