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Ahhhh ... very good: the left meter position "might" be a critical clue.

Two questions:

1. The left meter is the "multi-meter". What position is the multi-meter mode knob (to the right of the two meters) in? It will be on of "VCC", "IC", "COMP", "PO", or "SWR".
2. When the receiver is working, I am assuming that the multi-meter is no longer "mid-point", correct?

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-Mat Breton, N8TW

Hi all, I would like to share my technical experience with my FT980. After many many years of no use I wished to make a deep check and precise alignment of the equipment. I found three blocking failures:
- fail contact of the coax connector J02 on RF UNIT (symptom: very poor rx sensitivity and no output pwr in tx)
- output PA UNIT coax shield disconnection (instability in output spectrum and output pwr, in particular on low bands)
- open capacitor C3067 on AF UNIT (tx spurs of 240 Hz and harmonics in SSB, AM, FM)

After these mayor fixing I investigated on the frontend HAM bandpass filters: after a little retuning of the inductances the resulting behaviour was not so good due to frequency regrowth for frequencies lower than the bandpass regions. Probably this is due to the aging of the electrolytic bypass capacitors used in the pin diode switching band circuit. I added two new tantalum smd 47uF 16V cap and a 330 nF smd ceramic cap in parallel to C212, C130, C125, C120, C114, C109, C104, C97, C91. The results were very good: the spectral regrowths disappeared as you can see from the attached pictures. Only four bands are present on the pictures, but all the bands gain benefits from the additional bypass caps. It is important to use very low ESR capacitors, those used in switching power supplies generally fit the scope. Best if you can trust on specific caps datasheets for the ESR value. No significant difference in the response were noted in the bandpass region nor in the higher band frequencies region after the use of additional bypass caps.?

The 10m bandpass filters is a bit worse in terms of insertion loss and form factor, I'm investigating on it because I plan to develop a multiband transverter that will use the FT980 10m band.

The responses were carried out with AGC off, gain RF max,? input rx -30 dBm, output at TP1 on RF UNIT with a 450 ohm resistor in series to the spectrum analyzer input (it results in an additional loss of 20 dB in measurement, but it will not load significantly the circuit).?

The same check was carried out for the GEN (wide) band pass filters, but in this case adding low ESR caps in parallel of the existing bypass caps didn't result in significant improvements, so I don't recommend it.

Next steps will be a new 11m band pass filter and the complete check and retuning. Also 12.5 KHz FM channel spacing and CTCSS encoder are in my plans.?

Thanks for hosting me, best regards

Enrico IK2XEI

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Hallo Len, indeed I need the same replacement you are looking for. My plastic retainer clips cracked due to plastic material aging, I would like to share possibile development or research with you in order to fix them.
Thanks in advance?

Enrico IK2XEI

Thanks for your detailed reply.?

I did also noticed that while this is happening, switching the mode switch, all modes are shown selected on the display except FM. When the receiver is restored, FM is shown on the display and all works fine.
I stand corrected, the meter that sits half scale while this is happening is the meter on the left not the ALC.?

Hi Leo,

There are a couple of RX/TX relays in the FT-980. The most obvious one is the head which switches the path between the PA and the receiver. Three is another (multi-pole relay) on the REG board that switches a bunch of circuits. However, all these relays "default" to the RX position which would not match your symptoms (especially if the receiver was working when you switched it off).

I have found two potential things that DO cause this ... although the list is longer:
1. Intermittent connections, especially connector solder joints on the PCBs. A simple intermittent "RX G" or "RX 13.5V" line to one of any of the AF, RF or other boards would cause this. I had an intermittent connection on the BFO mixer xformer myself. These old single-sided PCBs are known for this type of thing.
2. BFO oscillator (or other independent oscillator) not starting up properly. This can happen due to parts going out of spec, flux contamination, etc. I had to replace a trimmer cap on an oscillator once to get the oscillator to start working again. You can sometimes debug these by switching the mode, and checking to see if you can receive in FM, but maybe not in SSB/CW (or some other combination). Then check the signal path charts in the technical manual.

If it happens again, I recommend first trying all different bands/modes/etc and see if it works in some but not others. Then, rotate the rig (yeah, I know it is heavy), and see if it is intermittent to mechanical displacement/vibration.

Just my thoughts,

Mat, N8TW



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-Mat Breton, N8TW

Hello Everyone,
Is there a switching relay that clicks over to turn on the receiver right after you press the power button?
If so, is that relay serviceable?
Tonight when I switched on the radio, the receiver did not come on. The ALC meter was at the half way point. All controls and buttons frequency display are fine. I powered it down, then tried power cycling it on and off several times. No change.
I came back later and tried again and it powered right up and the receiver turned on.?

罢丑补苍办蝉….

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Hello, Would anyone have a source or replacement for the 2 gray plastic retainer clips for each end of the carry handle? Can they be replaced with a newer type? Any possibility of anyone making a 3D printed version.
Mine are both missing, I know they tend to dry up over the years and crack.?

I believe the same clips are on my FT-ONE.
Thanks,

Thanks Dave,

Great news:?Roger VE7LB (the group owner) has already loaded all the FoxTango articles dealing with the FT-980 into the FIles section.

Look for "Files->06 - FT Club FT-980 Index and Information", and then open either the article index, or the articles themselves.

Hope these help ... they are great reading regardless ...

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-Mat Breton, N8TW

I modded a TS-930S with an Inrad roofing filter which also kills the AM bandwidth. How I ended up fixing that problem was to buy one of their blank roofing filter carrier boards and designed my own 6-pole filter to put on the carrier board. Switching between the two is done by another board and a set of relays; the 6-pole/6KHz B/W filter is inline with the 4-pole OEM in AM and the Inrad 8-pole/2.4KHz B/W unit is the active filter in all other modes. Both really work to tighten up the receiver.

A similar arrangement might be utilized with the '980. My "mule" will probably get the mod and I'll work out the particulars to apply to the others.

73 - Fred, N8YX

Inrad experimental #906 :) We have a section in the Files->Mods section. Inrad still has it in stock and sells it for $125, but it will have two side-effects I believe:

1. The additional insertion loss will slightly degrade receiver sensitivity (I believe)
2. While good for CW/SSB/Digi, it will limit AM/FM bandwidth I believe ... probably only noticeable for audiophiles.

If anyone in the group has one, maybe they report out on its effects and improvements? If anyone is going to throw one out, please send it my way :)

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-Mat Breton, N8TW

Hi Fred,

That VCO trimmer is a known problem: I replaced mine about 5 years ago for exactly that symptom. Anecdotal evidence says that the flux bath Yaesu used before wave soldering results in contamination of the ceramic, which eventually causes the value to go out of range of adjustment. Not sure if that is true or not, but it matches the symptoms for sure. I don't see that issue with other older ceramic trimmers ... so I suspect it was something yaesu did ... or maybe another component value going out of range (unlikely).

If you know the approximate cap range the VCO wants, I recommend getting a smaller trimmer value in that range ... makes it easier to find the sweet spot. The stock value requires a bit of patience and skill sometimes.

Just my thoughts ...

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-Mat Breton, N8TW

Hi Phil, There are two interfaces to the PC I can discuss ... the Audio Links, and the CAT control.

Audio: I personally use a USB Signalink to interface because:
1. It has a built in VOX that creates a PTT function, so I don't have to worry about setting up RTR/DTS in every SW program
2. It is galvanically isolated (audio rx, audio tx, and PTT): no grounds loops or noise transfer.
3.?
However, you can always direct connect everything up w/o isolation if you PC has a line in/out jacks. Have to get PTT somehow though.

CAT HW: My rig came with a Yaesu FIF-232 which I use mostly out of habit (and it matches the rig). Some in this forum have bought the USB cables and have them working ... but I will defer to them for advice on this.

CAT SW: For compatibility, the software doesn't need to directly support the FT-980 anymore: Hamlib has a "translator" software that will convert FT-980 into FT-2000 ... so if the software supports the FT-2000 you should be good to go. I tested this with a couple programs and it seemed to work. See the files section for instructions and advice on this ... but I bet you could get N1MM logger working if you tried :)


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-Mat Breton, N8TW

If we have all of the Fox-Tango Newsletters covering the '980...I seem to recall a filter change/addition that helps to fix leakage and blow-by issues. Inrad may stiock the required filters. Back in the day, these were Fox-Tango parts and I'll see the occasional unit show up on the auction site.

73 - Fred, N8YX

Been away from the group and on the repair bench for the last several weeks. There's a pile o' R-7000s which are gradually getting straightened out and that's been consuming a lot of my tinkering time.

One of my '980s - which I use for 75 through 15M SSB/CW ops - decided not to kick any more. The VCO circuit responsible for BFO generation wants to go full-rail as the rig warms up; the effect is that the BFO is shifted all the way up in frequency and the IF Shift control is inoperative. The bench mule '980 gladly donated its VCO-PLL Unit to the rig in the lineup, and all is well again. First steps are a recapping of the now-removed VCO-PLL Unit and replacement of TC4001 (the VCO Adjust trimmer) along with modifying it per the Yaesu Service Bulletin in the Technical Supplement. The board itself appears to be an earlier revision so the mods will aid stability too.

My -only- real gripe with the radio is that the squelch isn't all-mode, but I'm working on a mod for that involving a CD4066 IC to switch the Squelch potentiometer leads to either the FM circuit (when FM is selected) or to an add-in circuit for the other modes. FWIW, my FT-901/902s will get the same treatment.

73 - Fred, N8YX

Nicely done, Mat.

Not sure if everyone looks at Sherwood Engineering's receiver performance specifications, but the FT-980 was measured many years ago. It is interesting to contrast it with new rigs.


My thoughts from the table:
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-Mat Breton, N8TW

Just an update: I ran the ARRL DX Phone Contest 1.5 weeks ago. Not nearly as successful as the CW contest; band conditions weren't as good, and there was a lot of noise on 40M. I fired up the linear, but ran it lightly at only 700W or so output.

The FT-980 did great again of course. Without the sunspots it really helps to have the great receiver sensitivity.

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-Mat Breton, N8TW

The following files have been uploaded to the Files area of the [email protected] group.

• /05 - Mods/Wireless Article - FT-980 Breakout Bar.pdf

By: Mat Breton <i.m.n8tw@...>

Description:
Not really a mod, more of a convenience. But I use it a LOT.