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Author Topic: FT-897D lots of internal static  (Read 12597 times)
WW5AA
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Posts: 2088




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« Reply #15 on: April 06, 2010, 03:50:04 AM »

Before installing my FT-857D in the car, I set it up on the base. It compared very well with the Pro III and 751A. No unusual noise level or static sound. I have had it installed in the car for over three years without a problem. I would agree with the others, something is not right with the radio. Good luck.

73 de Lindy
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KE3WD
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Posts: 5694




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« Reply #16 on: April 06, 2010, 08:12:08 AM »

My "static" problems were evidently caused by poor factory soldering on Q1092. I've been using the radio for two months now, and I've only heard a couple of short static bursts since it was "fixed." I'm keeping my fingers crossed.

I'd order up a new Q1092 then, exact part number if possible. 

Sounds like you located a leaky transistor junction, sometimes the heat of resoldering will indeed serve to quell the leakage for a short time, but since you also say that you've heard "a couple of short static bursts" it sounds indicative of the problem. 

Best to replace a leaky bipolar transistor *before* the junction goes to short mode completely, which can take out other components in the circuit such as resistors. 

If a quick shot of Freeze Spray right on that transistor serves to quiet the static, then you've found the transistor with the leaky junction.  Replace it. 

Likewise, application of a small amount of heat to the face of the case on that transistor should make the static leak increase.  OK to use the tip of the soldering iron for that, just don't get carried away.  A short application in time is all that would be needed to ascertain the leaky junction. 

Heat makes it happen, Cooling it down makes it go away. 

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KE5KDT
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Posts: 47




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« Reply #17 on: April 06, 2010, 03:44:36 PM »

Greetings gentlemen.  I apprecaite all the input this post has created. It seems a few folks have had similar static issues but not necessarily the same components.  I really appreciate the components being identified.  I've had no issues lately with the 897 and will be using it portable for a while on internal batteries so we will see if anything crops up.  Sounds like carefully using a small soldering iron and some cool spray on the mentioned parts might help locate the culprit unless it has fled the scene.  As for me being chastized for repeating something I heard about Yaesu quality, I long for the day that folks were not so politically correct and so easily offended.  I still own two Yaesu's, two Icoms, eight Kenwoods, and lots of MFJ stuff, all of which works well for me.   I will post any findings on further use of the 897 and any recurrance of static noise and would appreciate the same from my fellow ham friends.  73s Bob KE5KDT
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LU8AOI
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Posts: 2




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« Reply #18 on: May 31, 2010, 04:42:54 PM »

Hi everyone.
I have a FT-857d also, and suddenly using it in RX, the static noise appears in all bands and modes without antenna connected (some of them are very noticeables), the s-meter goes crazy also when it happens. I have a service manual (i don't know which revision), but no Q1092 appears. Could you pin point me where is located this transistor in the circuit?.
Thanks you very much for your help with this.
Regards LU8AOI.
Leandro
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K4FX
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Posts: 166


WWW

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« Reply #19 on: June 03, 2010, 01:24:23 PM »

I have heard of several hams having issues with 20db over S9 noise at all times with no antenna attach with 857D's.  Several people have had this traced back to a bad batch of AM filters, CF1005. I don't know if the 897 was also involved, it wouldn't surprise me if it was.
One ham came out with a mod adding caps to the circuit claiming it was a design fault. However so many of these rigs are in service without any issues, I tend to think it is probably just a bad batch of filters.
If memory serves me, I think that they mentioned the age of the rigs having this issue as around 2 years old. The older rigs and the newest ones have not had this issue from what I have read on the Yahoo 857 users group.
Good luck

Bill K4FX
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LU8AOI
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Posts: 2




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« Reply #20 on: June 03, 2010, 03:39:37 PM »

Thanks Bill for your comments on this. I have read also something about a defective SMD AM filter too, but I don't know if my case. Examining the failure more closely (and with a dummy load attached and another receiver), this static sounds also can be heard in the TX audio, even with the mic gain adjusted at "0"! trying different modes, the more noticeable is AM, but in the others too. I think in my case should be something else, otherwise these filters has to be with the transmission...
What also fit to the pattern, it's mine also belong to that window of time (two years approx).
If anyone has experienced this strange behaviour, your input will be very appreciated.

Best regards,
LU8AOI
Leandro
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KE5KDT
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Posts: 47




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« Reply #21 on: June 22, 2010, 07:25:37 AM »

In conversations with  Yaesu service, they recommended I replace all three filters to handle the static problem.  I am still awaiting the last one before installing them.  They are only a few bucks each.  Bob
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WO4V
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Posts: 12




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« Reply #22 on: July 12, 2010, 09:00:41 PM »

Well folks, my 897 has developed this problem (the radio is about 2 years old). So far, I have removed the main board and touched up a couple of questionable solder joints, cleaned all the cable plugs and jacks, and put new heatsink compound on places where it needs to be, and tightened all the screws. This seemed to help, but the problem comes back occasionally. I found a mod adding a ground jumper from the trace for Q1092 to the main ground on mods.dk but I have not tried this yet.

I would really appreciate it if some of you who have posted here on this problem would re-post what the outcomes/fixes you have discovered. I would not be adverse to sending the rig into Yaesu or somebody who has fixed this problem for one of you. I will gladly heed recommendations from any of you for a repair facility that fixed your static problem. I really like this radio, but it is going on the tailgate at the next hamfest if I cannot get it to stop this...

Thanks in advance,

Dave
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DL1KD
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Posts: 1




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« Reply #23 on: January 23, 2011, 05:23:45 PM »

Hello together,
has anyone no an fix for this static problem? I have it now for 8 month. (VHF & UHF) But only from time to time. I can exclude a thermal problem. When i turn my 897D on (cold) an let it run a few hours, nothing happends. The problem still remains.  Angry

Thanks in advance,
Alex
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KE5KDT
Member

Posts: 47




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« Reply #24 on: March 20, 2012, 10:23:34 AM »

I made the original post on this and ended up sending it to Cal Fisher at hamrepair.com.  He found the following part defective, which others have identified on this post.  Evidently there was a bad batch.
H390054Z ALFYM455H=K 455khz Ceramic Crystal IF Filter 6KC
You can get this from Yeasu parts for $2.75 or so. 
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K1FJ
Member

Posts: 1




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« Reply #25 on: March 23, 2012, 08:30:48 AM »

I bought my FT-897D as a used radio about a year ago. The person I bought it from had it for about six months, and so it is likely under two years old. I have been using the radio mainly for listening to air traffic control in the AM mode. A few days ago the radio developed the same type of annoying S-9 level static posted by others.

I came across a fix published by AA7FV. His fix describes the mods for a FT-857/897, but the general schematic and architecture at the 455 kHz AM filter circuit is still valid. I made the modification to isolate the 455 kHz AM filter from any DC bias. I was concerned that maybe my 455 kHz AM filter was damaged by the DC that had been applied. After I modified the radio, I powered it up with the original filter in place and I had NO static at all. The radio now operates as it did before this static appeared. No loss in sensitivity. (I have a full up lab at home to check radio performance.)

An observation is that AA7FV mentions that the Toko Ceramic filters are not supposed to have DC applied to them. CF1005 is the only one that has DC applied to it. It is interesting to note that a similar Toko Ceramic filter, CF1004, is properly DC blocked. It is also interesting that when the ceramic filter generates static with DC applied, it can also couple that noise into the other modes besides AM. I suspect that there is a DC bias applied to the AM filter whether it is actively on or off. It seems like a sad decision by Yaesu not to add two SMD capacitors for the cost of a few pennies to preclude this from happening, especially since they did use two capacitors for the other filter.

One other observation. Before I made the modification, I notice that if the radio was off for a bit, and then turned on, the noise was initially gone. Then after a few minutes it would start out intermittent and then a full run of S9 static. So it implies that the filter can handle the DC for a period of time, and then whatever is inside starts to be affected by the voltage after some time. So the point is, changing the filter with a new one and not doing the modification may work, but time and voltage will eventually cause this noise to re-occur. It is important to make the mod and remove the voltage from the filter. I don't believe this is a "bad batch of filters", just a bad design decision by Yaesu.

Frank K1FJ
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KE5KDT
Member

Posts: 47




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« Reply #26 on: March 25, 2012, 08:50:16 AM »

Thanks for your input.  Sounds like some good troubleshooting.  I only see one problem with your conclusion.  You say that they will eventually go back to having the static condition.  If that is so then every 897 ought to develop this problem and the forum would be flooded with folks with static problems.  Fortunately, I don't see that happening.  I hope Cal was right and the problem is gone.  I have another 897 now and it doesn't have that problem.   Bob
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KB9MIE
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Posts: 3




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« Reply #27 on: February 16, 2014, 01:01:21 PM »

I'm late to this party but my 897D developed the static noise recently. I bought it in 2007 and used it for about 3 months per year since. I'd looked at these discussions and suspected the ceramic filters. After taking a look at the SMD boards I decided that discretion was the better part of valor and sent it to Cal. He replaced the defective CF 1005 , and DC blocked it, CF 1002, and CF 1003 with .001 microfarad capacitors on both sides of the filters He calibrated the Master Reference and the radio is now working well.
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KC9HVA
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Posts: 59




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« Reply #28 on: February 23, 2014, 07:33:49 AM »

you need to ship it back to the factory to get the three filtres replaced.  and at the same time it needs to have the bias current adjustments done in the finals . if the bias currents adj are done you should be able to run 100% mic gain with no problem 50% max without bias adj.
i had my ft897d done by the factory and able to run 100% mod with no problem.
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