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Old 10th Jun 2021, 5:52 am   #1
G7Michael
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Default Yaesu FT-480R off frequency

Good morning,
I'm a newbie here (although my knees let on that this does not apply everywhere), coming back to the airwaves after many years of fooling around with other things...

Due to my location, I always used an FT-480R both as base station and mobile. One of the reasons I went QRT was due to my 480 being off frequency. A friend at the time (sadly now permanently QRT) put it on his test rig and found it was off by 6kHz on both TX and RX...

Its a really nice thing, and I don't want to bin it. Does anyone know where I could send it for overhaul?
Very best regards
Michael
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Old 10th Jun 2021, 6:46 am   #2
dodgy-dxer
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Default Re: Yaesu FT-480R off frequency

Michael

Castle Electronics have a good reputation

https://www.radioworld.co.uk/blog/ca...unications-ltd

Fred
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Old 10th Jun 2021, 7:52 am   #3
Jon_G4MDC
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Default Re: Yaesu FT-480R off frequency

These develop interesting faults in the synthesiser. Quite often a frequency error at one particular frequency is a different amount or completely gone somewhere else. If you have a contant error across the whole range it is probably simply the reference oscillator has drifted.

Do you have anything with which to measure how it behaves? 2nd rig, frequency counter or some such?

This one was eventually fixed but not before some blameless parts were swapped out...In the end it only needed the tweaking of an inductor.

https://www.vintage-radio.net/forum/...d.php?t=158664
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Old 10th Jun 2021, 10:46 am   #4
G7Michael
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Default Re: Yaesu FT-480R off frequency

Quote:
Originally Posted by dodgy-dxer View Post
Michael

Castle Electronics have a good reputation

https://www.radioworld.co.uk/blog/ca...unications-ltd

Fred
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Thanks, Fred,

I'll contact them directly - a recommendation is always a good place to begin.
Best regards
Michael
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Old 10th Jun 2021, 10:48 am   #5
G7Michael
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Default Re: Yaesu FT-480R off frequency

Morninmg, Jon,
Thanks for that link - I'll have a read later... Unfortunately I dont have another rig or test equipmewnt now. I only kept this one by accident as it went off to a local friend who was an ex-government radio tech and then got left there. Quite remarkable that I got it back!
Thanks for your help
Michael
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Old 10th Jun 2021, 3:29 pm   #6
Steve G4WCS
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Default Re: Yaesu FT-480R off frequency

Ive a sig gen and a 2m radio with a recently calibrated reference oscillator. I could check it out on receive and transmit
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Old 10th Jun 2021, 4:09 pm   #7
mickm3for
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Default Re: Yaesu FT-480R off frequency

Hi this rig has cw so you could compare with one of the cw beacons my local is on 144.430 and is gps locked Mick
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Old 10th Jun 2021, 5:56 pm   #8
G6Tanuki
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Default Re: Yaesu FT-480R off frequency

Is the frequency-offset apparent on _all_ channels/modes?

If so I'd be looking for a failed capacitor in the synthesizer's reference-oscillator.

I remember something similar in 1980s Marconi two-way gear - the synth's reference oscillator had two small ceramic capacitors to ground, one from each side of the xtal. When one failed it shifted the xtal's frequency high enough to put your radio on the next-channel-up.
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Old 10th Jun 2021, 6:50 pm   #9
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Default Re: Yaesu FT-480R off frequency

Solder-sealed crystals can also age rather a lot.

If I remember rightly the FT480 has one ref for the main synthesiser and a crystals for carrier creation and it may do crystal pulling to approximate the 10Hz steps on the synthesiser.

So there are a few crystal oscillators to check.

I've got a spare FT480 in a drawer in the shack, but I've not fired it up or looked in the manual for many years.

David
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Old 10th Jun 2021, 7:15 pm   #10
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Default Re: Yaesu FT-480R off frequency

G7Michael, it seems that in the first instance you need some help closer to home so you can diagnose the symptoms more precisely.

I notice there is an amateur radio club in Hornsea which doesn't look far away from your Driffield QTH - of course one man's near is another's far, we don't know how you are set up for personal transport, but if you took the radio along to one of their meetings (circumstances allowing) I'm sure there would be someone of a technical bent there who can at least check the output frequency for you - maybe warn them in advance that you are coming so someone can bring a bit of test gear along?

Amateurs often have some spare kit that needs dusting off (Look at David, with his 480 sitting in a drawer) so someone at the club might well be kind enough to loan you something while you are getting your own radio sorted.

http://www.hornseaarc.co.uk/contact.html
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Old 11th Jun 2021, 8:32 am   #11
G7Michael
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Default

Quote:
Originally Posted by Steve G4WCS View Post
Ive a sig gen and a 2m radio with a recently calibrated reference oscillator. I could check it out on receive and transmit
Thanks, Steve. I have a new antenna on order, so when I get that set up I'll let you know!
Michael

Morning Mick,
Now didn't think of that one - that will at least give me a reference...its so long since it was used now it might have moved even more.
Thanks!
Michael

Quote:
Originally Posted by G6Tanuki View Post
Is the frequency-offset apparent on _all_ channels/modes?

If so I'd be looking for a failed capacitor in the synthesizer's reference-oscillator.

I remember something similar in 1980s Marconi two-way gear - the synth's reference oscillator had two small ceramic capacitors to ground, one from each side of the xtal. When one failed it shifted the xtal's frequency high enough to put your radio on the next-channel-up.
Good morning,
Yes, according to Dez its across all channels and relevent modes. I'' dig out the circuit diagrams...
Thanks!
Michael

Quote:
Originally Posted by Radio Wrangler View Post
Solder-sealed crystals can also age rather a lot.

If I remember rightly the FT480 has one ref for the main synthesiser and a crystals for carrier creation and it may do crystal pulling to approximate the 10Hz steps on the synthesiser.

So there are a few crystal oscillators to check.

I've got a spare FT480 in a drawer in the shack, but I've not fired it up or looked in the manual for many years.

David
Morning, David,
A man with a spare 480 just kicking around - excellent! In chatting around the local area I'm finding bits of test gear here and there that I'll be able to gather up, dust off the memory banks and start poking around...if you pardon the expression... Why do I think this coulkd be a lengthy process..? Ah well, it'll be good for me I'm sure!
Thanks for the info!
Michael

Quote:
Originally Posted by SiriusHardware View Post
G7Michael, it seems that in the first instance you need some help closer to home so you can diagnose the symptoms more precisely.

I notice there is an amateur radio club in Hornsea which doesn't look far away from your Driffield QTH - of course one man's near is another's far, we don't know how you are set up for personal transport, but if you took the radio along to one of their meetings (circumstances allowing) I'm sure there would be someone of a technical bent there who can at least check the output frequency for you - maybe warn them in advance that you are coming so someone can bring a bit of test gear along?

Amateurs often have some spare kit that needs dusting off (Look at David, with his 480 sitting in a drawer) so someone at the club might well be kind enough to loan you something while you are getting your own radio sorted.

http://www.hornseaarc.co.uk/contact.html
Thanks for the link. Yes, I was in contact with Hornsea club years ago. Geographically its not far, but its a bit of a trek to get there due to the roads. I think there was on in Scarborough (where I learned with Dez) but they might be QRT now. Certainly a lot closer than Hornsea. You've set me thinking though, so thanks for your prompt - re-connection is a good way to go!
Best regardfs,
Michael

Thanks to everyone for your time and efforts on my behalf - its very good to be in touch with the community again!
best regards to all,
Michael
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Old 11th Jun 2021, 9:56 am   #12
mickm3for
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Default Re: Yaesu FT-480R off frequency

Hi my ft480 was 3.5khz off it was the trimmer cap in the master reff osc on the pll board if i remember correct with rig display facing you it was on the LH edge of the pll board around the middle just touching/ pushing the trimmer cap caused fx to jump around
when trimmer replaced i just set fx to receive gb2vhf being my local beacon on 144.430 mhz has been ok since Mick
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Old 11th Jun 2021, 7:16 pm   #13
SiriusHardware
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Default Re: Yaesu FT-480R off frequency

Don't disappear just yet G7Michael, it is sounding increasingly likely that your problem is due to a 'stock fault' with the reference oscillator trimmer capacitor, if so, all you are likely to need is a replacement trimmer capacitor and the loan of a frequency meter or the use of some other frequency standard such as an off-air signal with a known accurate frequency.

Looks like the Scarborough lot are also still on the go:-

https://www.g4bp.org/default.php

When I suggested Hornsea I had made a quick crow flies measurement from Driffield Centre to Hornsea centre - the crow files distance to Scarborough centre is actually a few miles further so that's why I went for Hornsea originally, sorry.
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Old 12th Jun 2021, 12:27 am   #14
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Default Re: Yaesu FT-480R off frequency

The Des I associate with Scarborough, used to have an amateur radio shop towards the top of Columbus Ravine, called "Derwent Radio" but I'm afraid he's no longer with us and the shop is long-gone.

David
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Old 15th Jun 2021, 5:42 pm   #15
Damo666
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Default Re: Yaesu FT-480R off frequency

I can't really offer much in terms of technical help, but what I can do is say that many of these forum members really are worth their weight in gold. You're in very good hands here.

There are some very knowledgeable & selfless people on here, & they've been a great help to me both past & present.

Sorry for going off at a tangent, G7Michael, & I hope you resolve the problem.
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