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Hopefully there's a few folks out there still watching this group and can lend some advice.?

I may have made a mistake, and decided to buy an older/classic unit for my -first- HF rig. My thinking was to try to start with the basics and eventually work my way up to a more modern SDR transceiver. Anyway, I got it from a guy on Facebook marketplace who was moving to Texas for a new job and needed to clean house in a hurry.? For being around 40 years old this FT-980 does look immaculate, has the original owners manual and a MD-1 mic.? He did power it up to show me that everything "worked" at least from a lights / meters / band switching and VFO tuning perspective, although not hooked to an antenna to really prove anything and said he never used it because it was given to him.? Maybe that is my first mistake, but I'm trying to learn from them.?

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After I got home I connected a dummy load with a SWR / watt meter on it and was pleased to see that it would transmit right at 100w.? So this past weekend I strung up a dipole antenna tuned slightly above the center of the 40m band. Unfortunately, even with the volume (AF) and RF gain cranked I can barely pick up signals and the voices are all indiscernible. No matter how I try to fine tune the frequency, I can't pull them in and they are weak and garbled sounding whether I'm using headphones or via the built in speaker.? I was able to listen to CW on the lower portions of the 40m band fairly easily and they seem to have more clarity after adjusting the width/shift.? The FM mode is definitely seems louder, but maybe this is normal? ? I feel as if this station almost works.

I'm a little terrified of cracking the case open but have done fairly simple electronic repairs before replacing blown caps and so on, but I feel this is pretty daunting.

Based on what I have described, is it worth opening up to see if I can possibly locate a physical solder connection or visibly apparent failed component(s)?? I saw a few posts indicating this sort of problem, but I don't feel the unit has been abused from the exterior appearance.? Also, would there be standard components I would possibly need to replace just due to age of the unit that would? be the cause?

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Thanks for any tips and advice you can share!

Mike Nicholas, KQ4VKJ

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The FT-980 is still a great rig ... usually very repairable. IMHO, if we could fix the CAT/panel lockout issue and add a selectable roofing filter it would be superior to many DSP radios.

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I had the exact same symptoms in mine once: there are several things that can cause this however. I have a theory (a common cause in fact), but want to ask some questions first.

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So, first a few questions:

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1. Listening to the "static" level, is the background static significantly less on USB/LSB (LSB for 40M) than with FM (w/ SQL off), AM, & FSK?? Or is static the same, and it is just signals that appear reduced? Let's find out if this is purely "Mode" related.

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2. Putting it into "GEN" mode, can you tune to an AM modulated signal somewhere and see if you can hear AM fine?

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-Mat Breton, N8TW

Thank you Mat,?
When in GEN mode I can tune up AM radio stations and listen to them just fine.?

For your first question, the level of general noise/static FM mode is definitely much stronger than USB/LSB or FSK.

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Mike Nicholas, KQ4VKJ

So ... a common issue is in the radio is failure of the BFO (Beat Frequency Oscillator). This is often caused by a value shift in a variable trim capacitor in the circuit.

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But ... at first glance this does not sound like your issue: If we lose the BFO, then we will not be able to receive SSB (USB/LSB), FSK, and CW.? In your case you report that you can hear CW fine. You can see this by looking at the different "signal paths" by mode in the block diagrams in the manuals.

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Note that the BFO, width, and shift oscillators are tied together in a relatively complicated structure designed to cause canceling oscillator errors. You mention that you were able to hear CW better after playing with the Width and Shift functions. Normally, CW should be fine with both centered.

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Where I am: I am not able to totally eliminate the BFO issue yet.? There are two articles in the Files -> 05 Repairs section.? The first one describes how the BFO/Shift/Width works. The second one discusses how I repaired the BFO trim-cap, and also how I fixed an secondary problem (a bad transformer).

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If you have a multimeter, you will be able to remove the topcover, and use the multimeter to check if the BFO is working properly.? On page 23 of the Technical Supplement manual there is a paragraph on how to set it, and then how to check it (using just a voltmeter).?

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-Mat Breton, N8TW

Wow!? I went through checking the BFO value SHIFT setting voltages as you suggested and they were indeed *way off*.?
Once I was able to get them back adjusted to the proper voltages, all seemed to fall into place and everything started working and the USB/LSB voices cleaned right up.? Also, now when checking, I pulled in a ton of CW on the lower 40m and it is much cleaner than before.? I'm thinking the CW modes were also affected but just had nothing to compare to.?

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Thank you so much for your help Mat with this,? I do appreciate it!

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Best,

Mike Nicholas, KQ4VKJ

You are very welcome, Mike. Glad we were able to help!

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Just a note: it is possible, even likely, that the trim capacitor will continue to drift. You might need to repeat this someday ... or possibly even to replace it if at some point it drifts to where you won't be able to find a stable setting.

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P.S. Welcome to the group. There is a LOT of information on the radio in the Files section.

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-Mat Breton, N8TW

Hi, I struggled with the 30 MHz generator for a long time, then I installed TCXO 30,000 MHz 0.01 PPM, and forgot about the problem

Ur9ip,
Sounds very stable / accurate and a nice upgrade.?

Was it very expensive?? I wasn't finding anything with that spec PPM out on digikey.? Do you have a link to where you were able to buy it?
How much trouble did it take to install it?

Thanks,

Mike Nicholas, KQ4VKJ

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There is nothing complicated, we throw away the generator on the quartz, and instead we put TCXO 30,000,000 mHz