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Vintage Amateur and Military Radio Amateur/military receivers and transmitters, morse, and any other related vintage comms equipment. |
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6th Oct 2018, 11:24 am | #21 |
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Re: Yaesu FT290R Mk 1 squelch fault
Good idea Sparky, I'll try that. Thank you.
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6th Oct 2018, 11:53 pm | #22 |
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Re: Yaesu FT290R Mk 1 squelch fault
I'm delighted to be able to report a happy ending to this saga! The radio is now fixed. The culprit was indeed C104, which after tracing out the PCB tracks turned out to be the capacitor immediately adjacent to the discriminator inductor T1013.
C104 (pictured below) emerged minus one of its lead-out wires and looking very sorry for itself, with a blue-ish crystalline deposit leaking from its base. Some of this had contaminated the board and had to be carefully removed with a drop of solvent on a cotton bud. A replacement capacitor restored normal operation, the voltage on pin 4 of the MC3357P is now back up to 6 volts and stable, and the squelch operates properly once again. Many thanks to everyone for your interest and suggestions. Phil
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Phil Optimist [n]: One who is not in possession of the full facts Last edited by Phil G4SPZ; 6th Oct 2018 at 11:55 pm. Reason: Repetition removed |
7th Oct 2018, 12:06 am | #23 |
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Re: Yaesu FT290R Mk 1 squelch fault
That's good news. I'm a bit late with this but I just uploaded my copy of the FT290R schematic to the link below.
I created this a few years ago by pasting together several images from somebody else's scanned pdf. My version puts them together like a Bayeux tapestry but without losing resolution. Sadly the original pdf wasn't great. Otherwise the quality would be much better. But the image is something like 4000 x 1000 in size and it is much nicer to navigate than having the schematic broken up into several sheets. Try zooming in to see the full resolution as a standard HD monitor won't be able to display it properly unless you zoom in to just part of the image. I posted it up to one of the Yaesu groups a few years ago but thought it might be worth sharing here. https://www.qsl.net/g/g0hzu//RF%20Tr...90_schem12.jpg
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Regards, Jeremy G0HZU Last edited by G0HZU_JMR; 7th Oct 2018 at 12:15 am. |
7th Oct 2018, 12:23 am | #24 |
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Re: Yaesu FT290R Mk 1 squelch fault
Thanks, Jeremy. I have the full-length fold-out circuit diagram that came with the rig. It seems that no service manual, component layout or PCB track layout has been published anywhere.
Phil
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Phil Optimist [n]: One who is not in possession of the full facts Last edited by Phil G4SPZ; 7th Oct 2018 at 12:35 am. Reason: Photo updated |
7th Oct 2018, 12:53 am | #25 |
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Re: Yaesu FT290R Mk 1 squelch fault
That PCB does look clean! I earlier dug out my old 290R and had a peek inside to look for C104 and I can understand why you started the thread. I'd forgotten how cramped this radio is inside and it was just too difficult to work out where C104 is located without further dimantling.
It really is a shame there is no parts layout diagram for the PCB. My old 290R has sat unused for a long time now and is now full of black residue from the internal sponge. It looks to have rotted in some kind of way and I guess I'll have to clean it all out as it looks a real mess inside. I bought this on ebay as a non runner quite a few years ago with a low bid of about £35. Amazingly I won the auction and the fault was just the s meter was stuck over on receive due to an AGC fault. Otherwise it has a Mutek board in it and it worked fine after I fixed the AGC and aligned it all. However, I've never used it on air (i.e. transmit) in all this time! I keep meaning to put it in the car but never seem to get round to it...
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7th Oct 2018, 1:33 am | #26 |
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Re: Yaesu FT290R Mk 1 squelch fault
Hi. Out of interest what did you do to fix the AGC fault?
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7th Oct 2018, 1:47 am | #27 |
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Re: Yaesu FT290R Mk 1 squelch fault
I recall that the previous owner had already tried to fix the AGC fault and had left a mess with some parts soldersucked to isolate them and I think they gave up on it. I'm pretty sure I replaced the JFET Q1015 and a capacitor and cleaned up the mess left behind and it has worked fine ever since. However, I'm not sure this is a typical repair for this fault. It appears to be a common problem and I think the usual fix is to add a bleed resistor somewhere. But for this radio I just probed around with an ultra high Z DMM (several GigOhm input Z rather than 10MegOhm) and worked out what was wrong with this one. But I think there may be several causes for this problem and I may have just got lucky with mine as there doesn't seem to be a definite diagnosis for what causes it. Loads of people resort to fudging the circuit with a bleed resistor for example.
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Regards, Jeremy G0HZU Last edited by G0HZU_JMR; 7th Oct 2018 at 2:13 am. |
7th Oct 2018, 9:30 am | #28 | |
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Re: Yaesu FT290R Mk 1 squelch fault
Quote:
The black sponge had degenerated on mine too. I vacuumed the bulk of the remaining gooey dust away, then used some MEK solvent to remove the rest of the sticky goo. I stuck a sheet of paper over the inside of the lid. I do sometimes ask myself why I keep this radio, and my many other 'vintage' ham radios. The usefulness of any single-band, low-power, non-CTCSS-equipped radio is questionable at best!
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7th Oct 2018, 11:31 am | #29 |
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Re: Yaesu FT290R Mk 1 squelch fault
Well done on the accurate diagnosis and repair.
I keep my 290R2 partly because I've owned it from new and so we have a 'history' together, and partly because it is still the only 2 metre SSB radio I have. I have the official clip-on linear for it as well, so it is quite usable as a mobile radio. Most of my operation is simplex anyway. At one time I used to carry it with me on every ascent onto the high fells in the Lake District, but the level of SSB traffic declined to such an extent that I often found myself carrying its not insignificant weight all the way up a hill for no reason. However, that was before the SOTA scheme kicked off, so it might well find a new lease of life on the hills now. |
7th Oct 2018, 12:12 pm | #30 |
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Re: Yaesu FT290R Mk 1 squelch fault
Thanks very much! I've had it on monitoring S20 most of the morning. The squelch seems perfectly okay now. I have to check from time to time, as 2 metres is so quiet around here. In two hours I've heard one call...
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7th Oct 2018, 3:13 pm | #31 |
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Re: Yaesu FT290R Mk 1 squelch fault
And did you answer it?!
Gordon G7KNS |
7th Oct 2018, 4:13 pm | #32 |
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Re: Yaesu FT290R Mk 1 squelch fault
No... it wasn't for me! What you mainly hear is one station calling another specific station.
CQ calls on 2 metres are as rare as hens' teeth nowadays, although I did hear one this afternoon. I didn't reply to that either, because I don't happen to like the person who was calling. Never mind, this little episode has sparked a bit of interest in using my vintage ham kit more often!
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Phil Optimist [n]: One who is not in possession of the full facts Last edited by Phil G4SPZ; 7th Oct 2018 at 4:14 pm. Reason: Clarity |
7th Oct 2018, 7:04 pm | #33 |
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Re: Yaesu FT290R Mk 1 squelch fault
I like the vintage kit as well and have a 290 Mk1 also. Straightforward, does the job and not full of menu driven functions you never need or use.
Gordon |
8th Oct 2018, 10:18 pm | #34 |
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Re: Yaesu FT290R Mk 1 squelch fault
Agreed, Gordon.
You might like the postscript to this story; I have left the radio running for the past couple of days while I've been doing some painting, monitoring the FM calling channel S20 and the squelch is still working fine. This afternoon a CQ call came in from M0VCM/P, which I did answer as he was up on top of Brown Clee Hill running just 5 watts. I received an RS 55 report from my 2.5 watts, with my radio sitting on top of the wheelie bin on the drive with just its built-in telescopic whip aerial extended. It's probably fair to say that despite the oft-heard criticism that the '290 in its unmodified form was 'deaf', at least its transmit and receive capabilities were roughly reciprocal. Many people added the MuTek front end and subsequently found that they could hear a lot more stations, but couldn't work any of them!
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Phil Optimist [n]: One who is not in possession of the full facts Last edited by Phil G4SPZ; 8th Oct 2018 at 10:21 pm. Reason: Update |
8th Oct 2018, 10:59 pm | #35 |
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Re: Yaesu FT290R Mk 1 squelch fault
For the potential benefit of anyone else searching for this particular fault, I've posted a brief Success Story here.
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9th Oct 2018, 11:15 pm | #36 |
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Re: Yaesu FT290R Mk 1 squelch fault
Perhaps the final post in this thread... thanks to John, who mentioned in his post #3 the vintage FT290 User Group on Yahoo. I have finally been approved to join, and sure enough there is a drawing of both sides of the PCB available to members in the 'files' section, as well as a recent detailed article covering the wholesale replacement of all the electrolytic capacitors showing component placements and values. One to bear in mind for future reference.
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13th Oct 2018, 7:17 pm | #37 |
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Re: Yaesu FT290R Mk 1 squelch fault
Hi Phil, I'm guessing that you probably have the 290 all screwed back together gain now, but if it's still opened up, I wonder if you've done anything with the little bulb which lights both the frequency display and the meter?
Having just dug my 290 out of the cupboard, I find that bulb has failed, and a search of Google suggests this is common and is best dealt with by putting in a LED. There are articles giving a detailed description of what's involved, but unfortunately, getting at the bulb means lots of dismantling! . B
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13th Oct 2018, 10:37 pm | #38 |
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Re: Yaesu FT290R Mk 1 squelch fault
Hi Bazz. Indeed, it's all back together again. The bulb in mine had actually failed some years ago. I resisted the temptation to tackle that problem, largely because I have heard too many horror stories concerning damaged displays! It seems all to easy to end up with no display at all, so I thought it best to leave well alone, given that the lack of a backlight is of minor consequence.
Good luck if you plan to tackle yours, though! If you succeed and write about it, perhaps I will be encouraged to have a go myself...
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14th Oct 2018, 12:00 am | #39 |
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Re: Yaesu FT290R Mk 1 squelch fault
I hadn't heard of displays failing, but on a piece of equipment of this age, that's not all surprising. It's a terrible bit of design!
B
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14th Oct 2018, 12:11 am | #40 |
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Re: Yaesu FT290R Mk 1 squelch fault
I don't think the display 'fails' as such; it is just very easy to break it in the process of replacing the bulb
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