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FT991 Yaesu : Pannes rencontrées Empty FT991 Yaesu : Pannes rencontrées

Message  F5PBG 1/11/2016, 22:18

NOTA IMPORTANT : N'apparaissent dans ce compte rendu que les équipements en avarie. Sont passés sous silence tous les avis de possesseurs satisfaits du FT991, très nombreux.

Ce sujet recensera les pannes sérieuses rencontrées sur le FT991.
Je commence par indiquer que si je m'intéresse à ce poste, c'est qu'il fait partie des postes les plus intéressants de sa catégorie (en sélectivité notamment).

Avril 2015 / France
Fonctionnement correcte en VHF-UHF mais dysfonctionnement en HF (notamment au niveau puissance émission) Arrow  Retour sous garantie 5cac

Avril 2015 / France / n° série 5E050171 :
Touches de l'écran tactile inopérantes Arrow  Retour sous garantie (4sgu)

Les écrans tactiles sont manifestement une source d'inquiétude sur le long terme,
cela n'arrive pas que chez Yeasu mais aussi chez ICOM cf. ce lien (cliquer ici)

Mai - Juillet 2015 / USA / Australie : Panne de PA après utilisation en AM
Ok, I've been a big supporter of this radio but decided to run AM mode for the first time and I've got the dreaded output power issue.  Have done all the firmware updates and full reset twice.  I'm getting about 5 watts output max although radio is set for 40 watts.  External power meter shows the radio does an initial spike to 40 watts then drops to almost nothing.  All other modes have normal output power.  SWR is low and does the same with a dummy load.  Ideas...or send it back?

73 Jim, N7JS
Can I ask if you guys with the blown transmitters have been using CAT commands to control the radio before they blew up? The reason I an asking is that after playing with CAT control of my FT-911 weird things started happening (like odd modes being selected, and power-on not remembering last used frequency and mode), and the only way to get it working properly again was a firmware reset to factory settings.

I seriously suspect bad CAT commands being able to corrupt the internal operation of the radio, and I'm just wondering if I'm lucky I didn't transmit before I did the reset or I might have suffered the same fate with blown finals.

Steve VK5HSB
My FT-991 is at Yaesu right now due to very low output on the HF bands.. less than 2 watts on 80 meters despite the radio set to 100 watts.

It happened during Field Day. I was using N3FJP's contact logger with an LDG YT-1200 tuner, which were both connected to the CAT port. The software worked flawless once N3FJP updated his ACL program. The tuner also worked great.


Pas d'information sur les conditions d'utilisation lors de la panne des PA concernant les cas ci-dessus, mais il est utile de rappeler : Puissance max en mode AM/FM/Mode numérique = 30% de la puissance max du PA soit dans ce cas présent 30 Watts. Si vous ne respectez pas cette précaution, ne vous étonnez pas que votre PA lâche un jour,
quelque soit le poste utilisé...

PA burning :
Both my 991s failed on 2m ssb and both failed after extended QSO 2 hours.Cheers Grant vk6ngs
Autre panne de PA - Retour de réparation - novembre 2015, désignation des éléments changés d'après la facture :
2 EA   FET RD100HHF-101

2 EA   J24275180 CHIP RES. RMC1/2 180JTE   FT-1000MP

1 EA   AH057M514 WHS6
Janvier 2016 a écrit:Hi
Just started to be happy with my new 991 setup , had it working great now on all digi modes , only problem was internal ATU did not get match on 80 or 160m.
i had used a LDG tuner before and it worked really well and got a good match on all bands for me so i purchased a LDG Z11Pro yesterday and have just been setting it up, with the z11 it will tune as soon as it senses RF and a high SWR, sure i did that fine, i had the radio set to about 15 watts (my normal power level for digi ) and gave a quick shout out into the mic, the tuner kicked off and after a sec or two gave the green led saying good match, i tried this on all bands and it was going well, got to 80m and this time it took a few more seconds to get a match, afterwards i noted the power meter was barely moving now and now i have have little output on the lower bands into a dummy load. on higher bands the output level comes up a bit, 7 watts on40 -30 watts 10m, on 6m and 2/70cms it seems fine.
anyone know the cost of new finals?
is this radio weak on its output protection side, in 30 years of playing radio this is the only one i have every blown a output transistor on, any comments?

Mars 2016 - PE1RBR - n° de série : 5J170387 - Panne de puissance sur 1.8 MHz = 20W max et 3.5 MHz = 50W max
Retours d'expérience ci-dessous très complets faisant apparaître comme origine de la panne un mauvais courant de repos des PA en sortie d'usine (d'après le réparateur). C'est le même problème rencontré parfois sur l' IC7000 dont les PA sont similaires. En conclusion, suivre la procédure de contrôle des courants de repos pourrait être intéressant cf. manuel de service :

Serial number: 5F070389
Firmware was updated 25 JULY 2015, using updates published 24 JULY 2015:
MAIN: V02-02
DSP: V01-04
TFT: V01-02
C4FM: V02-10

Purchased: 3 JUNE 2015 from Strictly Ham, Melbourne
Country: VK
Faults: Decreased Power on HF ~30Watts only. No movement of ALC bar.
Comments: Excellent audio reports on 7MHz local rag chew using ~20Watts. Performed well using HRD + WSJT-X in WSPR mode, QRP 5Watts. I had to increase HF Power Out to get those 5 Watts on my PWR Meter, and initially incorrectly attributed the problem to low audio levels from WSPR via Ham Radio Deluxe to the FT-99 1s soundcard! I began using the radio at QRP levels as a matter of principle, having experienced problems with stray RF energy sneaking back via USB cables etc into the computer.  
Tx OK on 50Watts on VHF/UHF. Rig firmware was updated in an attempt to see if that would fix the above fault. There was no effect. I did note that some WIRES-X functionality was meant to be introduced with this latest firmware upgrade, and although a WIRES-X button has appeared on the F M-LIST menu, it is greyed out. There is one other amateur in town who has a WIRES-X node, so we are waiting to see what the new function in my 991 will do.

The rig is currently in transit to Melbourne for repair.The technician informed me that he had seen the symptoms displayed by my before, and that it was highly likely that they were related to the bias current to the finals having been set too high in the factory. In my case only one final has blown, so allowing me to Tx at low power but not the full ton.

I have a FT-991 SN 5J1703xx.
I have a friend who also has a FT-991 SN 5J1703yy (around 50 units before).

The symptoms observed are/were:
- very important ALC deflection with the default settings
- inconsistent ALC deflection within the same bands even if connected to a dummy load
- some units had their HF PA MOSFET destroyed out of the box or quickly after few hours of utilization
- abnormal SWR report done by the transceiver even if the swr observed using an antenna analyzer or with an external swr meter was low.
You can find a lot of videos on the Web about these issues.

We could observed the symptoms on both units connected to a dummy load: incorrect ALC behavior.
Another friend, ham for nearly 40 years, could not explain the behaviors observed.

After the update of the latest available firmware dated of February 2016, it seems that the problems were less important: better (good) ATU behavior from my point of view.
Following the informations I got from the reseller, it seems that the idling current for the HF MOSFET were set too high at 1.8 A for each instead of the 1.5 A as recommended in the FT-991 TECHNICAL SUPPLEMENT.
Other users reported asymmetrical idling current settings on the MOSFET.

I sent my transceiver back to the reseller.
He set the idling current to 1 A and installed a protection diode.
After that, the ALC alignement procedure is needed unless you still have some strange ALC behavior when connected to a dummy load: no ALC deflection at all with the default settings (no equalizer, no Proc, default value of mic gain at 50) on some portions of some HF bands.
I performed it.
But I have now only 90 W on the 12 my bands but now a consistent ALC deflection on all HF bands.
My feelings: if the idling current for the MOSFET are set to the 1.5 A and then the ALC alignment procedure is performed, the behavior of the ALC and the output power should be as expected.
But, as stated by the technical supplement, a complete alignment should be performed after a hardware change.

An information found on eham.net says that all FT-991 with a serial number 5N or later should not have any issue at all.
Perhaps someone with a FT-991 with s/n 5N or later can comment this.
Some users report that their "early s/n" FT-991 was correctly fixed by their reseller and now the transceiver is performing very well.

I regrets the reaction of Yaesu on this crisis.
There was no communication at all about this.
I sent two emails (1 from the contact page on the Web site and one directly to someone with I was in contact for my FTdx-5000) but I did not receive any answer at all.
At least, an answer like "this is a known problem. Please contact your reseller for fixing under warranty" would have been correct.
But nowadays, with Internet, everything is known around the world and also very quickly.
The FT-991 is a great transceiver.
But now, it suffers of a bad reputation.
>From what I could see from my exchanges with the reseller, it seems that they were not informed by Yaesu of the correct fixes needed: he did not set the idling current to the value mentioned in the technical supplement.
Or the technical supplement I found on Internet (Google is your friend...) has been updated in a more recent version.

The FT-991 is a good rig when it is correctly aligned.
The receiver is very good and the transceiver audio is very good when you found the good settings of the equalizer.
The menu systems depends on personal preference.
The possibility to customize the four buttons differently for each mode is great.
Would I recommend the FT-991 to someone?
Probably yes even if my unit is not yet completely fixed.

Nicolas F4FXH

Juin 2015 : VFO HS (IV3NEP)

Août 2015 : VFO HS (OE3JTB) - Autriche / N° de série 5F060*

Janvier 2016 / Australie : Problème de VFO également rencontré par VK8KMD lorsque la température augmente (température ambiante de 29°C).

Juillet 2015 / France : Plantage logiciel lors du passage de VHF à HF nécessitant un reset du poste

Août 2015 / USA : Bug de la boite d'accord
From:"Jim Marr jcmarr4@mac.com [Yaesu-FT-991-group]"
Date:Mon, Aug 10, 2015 at 7:39 AM
Subject:Re: [Yaesu-FT-991-group] FT-991 antenna tuner strange behavior

Generally my FT-991 has been working well for me up until this strange behavior today that occurred when I was preparing to check into a 40m net on 7.185 MHz LSB. I set A=B (to set the split frequency to the same as the dial frequency based on some observations reported in this group that doing so helps ensure that the antenna tuner works), set RR PWR to 5W and initiated a tuner tuning cycle, which appeared to proceed normally to completion. I then set RF PWR to 100W and proceeded to check into the net but folks on the net said that my signal was unusually weak and I noticed the PO meter was only showing about 20W. Fearing that I may have had a PA failure that others have experienced, I turned off the radio and used another radio for the net.

After the net, I turned the FT-991 back on, dropped power to 5W, changed the Meter to SWR and noticed that the SWR was full scale (infinite). Seeing that, I initiated a new tuning cycle that, as before, appeared to go through the tuning cycle normally (not remembering its prior tuning; a first indication that something might be amiss) but the SWR remained full scale. When I switched the tuner off, the antenna SWR was about 1.5:1 on this frequency. Switching the tuner back on, doing another tuning cycle (full cycle again), resulted in the same full scale SWR.

I then switched to CW on 7.050 MHz using the preset band stack setting (where the antenna SWR is about 3.0:1), set A=B, turned the KEYER off and activated the tuner, which completed a tuning cycle normally, with resulting SWR about 1.0:1. When I set RF PWR to 100W, I observed 100W out on the PO meter.

After this, I went back to 7.185 MHz LSB (again using the band stack setting) and now the tuner was able to achieve about a 1.1:1 SWR on 7.185 MHz and I was able to achieve 100W PO. The radio has continued to work normally since then.

I do often use CAT with MacLoggerDX but wasn't using it during any of the above described events, although I might have been using it prior to the radio's previous shutdown (I honestly don't remember). I haven't had an issue with this previously, even when I forget to stop MacLoggerDX prior to turning off the FT-991 (although there might be a race condition here that I was just lucky to have missed until this time), so I don't know whether the use of the CAT interface contributed to this strange radio behavior or not.

For reference, I purchased my radio in June 2015 (S/N 5G080451) and it is still running the 3/20/15 software versions (Main V01-13; DSP V01-02; TFT V01-02; and C4FM V02-10) that came with the radio. I've been waiting to see how stable the 7/24/15 updates are before doing those updates.

I don't really expect anyone to know what happened here but I thought that it was worth adding this event to the database of the FT-991 antenna tuner behaviors.

-- Jim AA6QI
That pretty well sums up my experience with the ft991 tuner. I believe this tuner was not engineered properly by factory engineers. Until they provide a fix, this radio has a non functional tuner. I believe that is why people are blowing finals. Check my previous posts on this subject. Of course the immediate fix is an external tuner. Please post if you find a solution.
Carl K0YCR - Mon, 10 Aug 2015 08:19:08 -0700

Août 2015 / France - Département 22 : Panne du PA HF 6cht
Septembre 2015 / France - Département 61 : Panne du PA HF 4gop
Novembre 2015 / France - Département 61 : Panne de réception HF 4gop
Encore une nouvelle panne sur mon Yaesu FT-991. Un matin j’allume le poste, j’écoute la bande 80m donc le poste fonctionne à merveille,
je passe sur le VHF sur 145.700 MHz pour écouter le relais R4, puis après je reviens sur 80 mètres et
là plus de réception sur la bande HF, donc avec le préampli 1 et 2 un peu de réception mais sans plus.
Donc retour chez B**** E**** , et pour moi fini les Yaesu car je n’ai eu que des problèmes.

Janvier  2016 / US (KDØSZT) : Panne du PA HF (déjà réparé en septembre 2015)
FET replacement - AM Repairs - AH057M514
I called the service warranty and asked them what had been done to fix the rest of the radio that was allowing this repeat failure to continue.
Without specifics they assured me that the real problem was fixed.

Some have complained about the behavior of the tuner.  The internal tuner obviously isn't very good but perhaps even more troubling is how fickle the thing is.
I can tune a frequency on 40 meters, on a resonant antenna mind you, come back to it later and it will indicate high SWR.  
Attempts to tune the frequency again may or may not result in an acceptable tune.  
This is true even after the repairs they made.

Avril 2016 : Panne de PA - US
After having 2 Elmer's checking out my 991 and finding the finals are blown, I'm sending the rig back to Yaesu so they can sort it out. Hopefully this will solve my HF issue and I can get on the air.
73 - K9FBA James

Avril 2016 : Panne de PA - FR - Dept 22 6CHT
A l'allumage au moment où j'ai voulu faire qso sur 80m, puissance réduite 50 watts et 40 sur 160m.
Puissance correcte sur les autres bandes.

Avril 2016 : Mise en veille du VFO  - FR - Dept 77 6HFH
Au bout d'une heure d'écoute sans toucher au poste, le VFO ne fonctionne plus, voyant VFO disparu, HP gauche clignote
Le poste refonctionne en appuyant sur touche "UP" ou "DOWN". Une RAZ du poste ne change rien.
=> Changement de la carte principale du FT991.

Juillet 2016 : Dysfonctionnement AM  : Cas isolé ? - USA
Tweaking the audio settings is a superficial fix for a more basic issue that the FT991 has.

The "supposed" AM TX carrier level fix that everyone claims is the fix is also lame as this does not address proper power output calibration and AM issues on the higher(50MHz and above) bands. Try your rig on 6 meter AM on 50.400, without audio EQ and verify that the power output metering tracks correctly on the meter when tinkering with the AM TX carrier level.

Yaesu is struggling with this issue. I sent my FT991 back in January of this year. They performed an alignment and the rig still had AM ALC issues on 6 meters and above.

A properly modulated AM rig will display upwards power peaks on your power output meter. The FT991 in AM mode has DOWNWARD power output on modulation peaks. You should be able to accomplish a fully modulated AM signal WITHOUT audio EQ with a carrier level of 25 watts. Other manufacturers such as KENWOOD and ICOM easily demonstrate this.

Why is Yaesu struggling with such a basic form of modulation ?

In early June I sent my FT991 back to YAESU service in Cypress, CA after extensive conversation with Wes Grey (Service Manager) and Tim Factor (Service Tech) at the Dayton Hamvention. I had emailed Wes numerous times and did not receive any responses from him about this issue. They finally acknowledged that my statement that the FT991 has an issue with poor AM on the higher bands was verified. They agree with me. They still have my FT991 as of today(7/30). So far this year since I bought the FT991, the RIG has back in the CYPRESS service center for a cumulative total 10 weeks excluding shipment time of 1 week each way from the east coast. If you include shipment time, I have been without my FT991 for 3 months total now.

I have been calling Wes Grey on a regular basis and I have yet to hear feedback from him about when Yaesu is going to address this issue properly.

The AM issue has existed since 2015. Why is Yaesu struggling with this issue ? It seems all related to ALC. I understand there are extensive PA issues on this rig. What is up with the design of this rig ?

I think the FT991 is a good rig otherwise. It functioned well while I had it in the shack. Now it is probably sitting on a shelf in the service center collecting dust at this point. $1200 of my hard earned money just sitting there waiting. I also got the $100 rebate when I bought it which was immediately burned up when I shipped the unit back to the CYPRESS service center.

Will Yaesu come through on resolving this issue soon ? We all need to be more vocal about this issue with YAESU. We need to let them know we need a proper resolution on this issue.Call YAESU and push the issue. I am certainly pushing the issue with them but I need support from the rest of the FT991 owner community.

Stephanie WX3K

Septembre/Novembre 2016 : Panne de boîte d'accord - FR - Dept 22 (F6CHT) et Dept 24 (F6EJW)
Ros infini sur 7 MHz

J'ai une vague intuition que la boite d'accord n'est pas étrangère à la série de pannes de PA. Personnellement je ne l'utiliserais pas.
Parmi les avis qui vont dans ce sens :

W2CTX - Septembre 2016 a écrit:Yes, I was using the internal tuner, but no more! I have it disabled and use an MFJ-939 now. In my case, Harsh wound up replacing both the tuner and the finals and realigning the radio. In my case, whenever the tuner was on, SWR on 40M went off scale high. When it came back, the internal tuner worked for a few times then began intermittently doing the same thing. I will not use the internal again lest Is another set of finals!
W6ZAR - Novembre 2016 a écrit:Seems like my radio also is having issues with the antenna tuner. It's intermittent and seems to randomly tune to whatever. I tried it last night on the same frequency 3 times with 3 different results. I run a 80m horizontal loop that plays well on most bands but needs some help on a portion of the 20m band so I hardly ever have a need for it. Radio is a few months old so I guess I will have to send it in for repairs. Maybe they also can fix my multi knob which always had some play in it. I am getting into digital modes and just figured out how Fldigi and N1MM works so hopefully they won't have it too long. Love the 991 as my first HF rig.
73, Ryan
F6EJW - Décembre 2016 a écrit:Plus de puissance en sortie - Retour en garantie
K0HCV - Juin 2018 - Dégagement de fumée a écrit:My FT-991 literally went up in smoke the other day. I was talking with a friend on a UHF Fusion repeater when smoke started pouring out the back of the radio. I immediately turned off the power and disconnected all cables from the back. There was so much smoke I was concerned for a moment that it was on fire. It has taken several days to get the smoke smell out of the shack.

I took the top cover off and removed the inner cover and found burn marks about the size of a quarter on the underside of the cover. I looked at the V_U-PA UNIT board and found an area about the size of a dime next to RL4501 and L4533 that was melted. The components were totally gone with melted solder in their p lace and the area was completely blackened.

I bought this unit in January of 2015 and its serial number starts with 4N02 so it is no longer under warranty. I sent it back to Yaesu and their repair estimate consists of replacing the V_U-PA UNIT and realigning the unit for $261.

My question is has anyone else had this experience. I have another FT-991 with a serial number starting with 6J33 and I am wondering if I will have the same problem with it. I sometimes leave my radios on but unattended and now I'm thinking that may not be such a good idea, at least for the FT-991. This may have had the potential of setting my shack on fire if I had not been present.

Yaesu has given no explanation as to why this happened. I have no schematic so I don't know what part of the circuit these components were in. The obliterated components appeared to be chip components of some kind so unless there was something else on the underside of the pc board I can't imagine what caused them to expire.

As an aside the SWR of my VHF and UHF beams are well below 1.5:1 and have been in use since before I purchased the unit. I have been using the unit on HF in FT8 mode with no problems.

A bientôt,
Ludovic - http://inforadio.free.fr

Date d'inscription : 08/06/2008


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