FT857D display zebra

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VK4TI
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FT857D display zebra

Post by VK4TI » Sat Jan 10, 2015 1:15 pm

Ok my not old never mobile FT857D has developed some zebra stripes on the display , I need some instructions about disassembling the head and ideas about what might be wrong , I have some clues but who has fixed one pls

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Re: FT857D display zebra

Post by VK2SL » Sat Jan 10, 2015 3:16 pm

Seems like it might be a common problem with the 857's. The display in my tranceiver seems to develop the "zebra" problem with large changes in temperature. Not sure there is an easy fix but I'll certainly be keeping a close eye on this discussion.

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Re: FT857D display zebra

Post by VK4TI » Sat Jan 10, 2015 3:54 pm

If I can get it apart I think it's a simple solution ( a guess) , the interconnects between the electronics and the rear of the lcd , its like a carbon sponge finger that needs a clean and dry if what I am told is correct ( and that tech should know) as he works on other machines with a similar problem from the commercial world but how to strip the display and head without damage

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Re: FT857D display zebra

Post by VK2JDS » Sat Jan 10, 2015 10:20 pm

internet problem, multiple posted
Last edited by VK2JDS on Sat Jan 10, 2015 10:34 pm, edited 1 time in total.

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Re: FT857D display zebra

Post by VK2JDS » Sat Jan 10, 2015 10:26 pm

................................................. looks like the duplicates cant be deleted
Last edited by VK2JDS on Sat Jan 10, 2015 10:36 pm, edited 2 times in total.

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Re: FT857D display zebra

Post by VK2JDS » Sat Jan 10, 2015 10:27 pm

I have had 2 of mine fail, the lcd has a flexicable which connects to the control panel pcb. mounted on this plastic cable is the lcd drive chip.
the chip goes dry jointed underneath itself.
there are no pins visible as the chip and its contacts sits directly onto the plastic flexicable, so it cant be resoldered.
perhaps a heatgun might be usefull , but a soldering iron with a flat end didnt fix it.
The only option was to replace the lcd and panel, the part number CS2140401 AH007M000 PANEL-UNIT $ 179.99EA USD
i replace mine by ordering from america, and yaesu over there will pack and post for you.
73 Dave vk2jds

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Re: FT857D display zebra

Post by VK3MIX » Sat Jan 10, 2015 10:37 pm

I've just recently had mine repaired for the same issue - sent the radio to JNB Electronics in Thomastown, it was repaired under warranty as the radio is only going on two years old. It seems this issue occurs when the head unit is left in direct sunlight.

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Re: FT857D display zebra

Post by VK4TI » Sun Jan 11, 2015 1:39 pm

It seems there are several issues , often occouring after warranty and considering there are more than a dozen iterations of the radio with differing firmware and other options certainly the radio head has it's own set , only one who has repaired one in the asking and no specific suggestions as to disassembly , certainly my radio was unpacked and never moved but with the heat last week looking like a related incident .

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Re: FT857D display zebra

Post by VK4BVI » Sun Jan 11, 2015 3:29 pm

Unfortunately this is a commonly documented issue.

There is a lot of discussion and remedies on the FT-857 Google group, along with possible causes.

It does not appear to matter whether the unit sits in a shack (like mine does) or is in a mobile situation, sooner or later the stripes appear.

Ron
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Re: FT857D display zebra

Post by VK4TI » Sun Jan 11, 2015 4:05 pm

It would help heaps if there was a common cause and effect , I guess we will find out shortly , damn good radio spoilt by a simple problem

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Re: FT857D display zebra

Post by VK2EM » Mon Jan 12, 2015 7:20 am

Having repaired many LCD displays in the course of my job over the years, I can tell everybody what the problem nearly always is, and how to fix it, if its possible to disassemble the display.

Between the printed circuit and the glass display, (in a slot), there is a rubber sponge-like piece, which has conducting strips imbedded in it. This rubber piece (about 2 x 3 x ?mm) is the only conductor between the LCD and the PCB.

If it is possible, the display assembly has to be disassembled, and the conducting edges of the sponge, the PCB, and the conducting edge of the LCD all have to be cleaned very lightly with Isopropyl alcohol, using a cotton bud. When dry, reassemble the display, and the problem 'should' be solved!

In the past I have used Methylated spirit, which is basically the same, but it has additives in it, so before it is allowed to dry, the parts are wiped dry with another, clean, dry, cotton bud!

Good luck... Bruce VK2EM
73
Bruce VK2EM

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Re: FT857D display zebra

Post by VK4TI » Mon Jan 12, 2015 7:40 am

Thanks Rod for confirming what I have been told , when time permits I will go see the tech and get it cleaned , he has done a large number of commercials units so I am hoping your correct , of course stripping is a concern
B

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Re: FT857D display zebra

Post by VK2JDS » Mon Jan 12, 2015 12:05 pm

Hi Bruce, in the case of the ft857 what you describe doesnt work
There is no conductive rubber sheet on these and the lcd is directly bonded to the flexicable.
No amount of cleaning will solve the problem , which is, that the drive chip is directly bonded to the lcd flexicable and it goes dryjointed under the chip
I can post pictures if anyone would like to look at the problem, i have 2 at home.
I am also a radio tech by trade by the way
73 Dave vk2jds

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Re: FT857D display zebra

Post by VK2JDS » Wed Jan 14, 2015 7:50 pm

Today I got to take the pics of the 857 display unit so you can see whats going on
topside.JPG
upper view of the display lcd showing the chip embedded in the flexicable and how its all soldered to the control pcb
underneath.JPG
here we can see the chip in the underside of the flexicable with the lcd directly connected to the flexi
you can clearly see there is no strip of carbon conductor like in the old motorola displays, these units are totally different.
I hope this will explain to you all that there is no easy fix for this problem
73 Dave vk2jds

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Re: FT857D display zebra

Post by VK4TI » Wed Jan 14, 2015 8:02 pm

""Today I got to take the pics of the 857 display unit so you can see whats going on

pics snipped

you can clearly see there is no strip of carbon conductor like in the old motorola displays, these units are totally different.
I hope this will explain to you all that there is no easy fix for this problem
73 Dave vk2jds ""


Tnx for that , frustraiting as its a few days outside warranty but I have suggested it being so common they should come to the party , I doubt it will happen so have a used spare possibly organised just in case , still quite usable but obviously irritating . Damn good radio with lots of enhancements and tremendus performace let down by crap assembly
Tnx
B

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Re: FT857D display zebra

Post by VK2JDS » Wed Jan 14, 2015 8:34 pm

I have worked on many 857's for add-ons, mods, and repairs, and they are a terrific radio.
when 2 of mine failed with the display problem spending the money to repair them is well worth the investment compared to spending 1500 dollars or more on a different but similarly capable set.

The part number (and price in US dollars) i gave in the previous messages is for the complete panel and lcd. thats the retail price out of the US plus freight etc
The replacement job is within the capabilities of a suitably equipped hobby level person.
Take care when dismantling the head unit and reassemble exactly the same and it will all work. You are simply replacing the pcb inside the case. Only one plug has to be desoldered off the old pcb so its not hard.
there are no alignments required. The lcd has a sheet of thin protective plastic over it which you can pull off before refitting it into the head unit case.
screw the back on and reinstall it and off you go.

for more detail of the repair i can take some more pics if required.
but if you are unsure then send it to a dealer like Lee Andrews or a good repairer like RFrepairs to do the job, then you know it will be right.

73 Dave

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Re: FT857D display zebra

Post by VK4TI » Wed Jan 14, 2015 9:46 pm

Thanks Dave for the offer , if you have time , I have a friend who is a 30 year verteran of radio work including M so he will be doing the work as he has the tools , Im just a network and comms guy
B

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