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My FT817 has suddenly stopped transmitting on 2M all modes. Its fine on all
the other bands. I have tried the master reset with no result. Does anyone
have any ideas?.
Regards Tim M0AFJ
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Hi i found this when my FT817 did not output power on 2m and it was the Diode that had gone bad,
Good Luck, Dave 2E0DMB
so on Pin 8 of Q3003 on the PA Unit is a voltage called V-TX that
switches the output of the PA FINAL thru to the 2 Meter Low Pass Filter.
There it passes thru the Relay RL3001 which for 2Meter is closed from the
moving contact to the Normally Closed (Black) contact which passes the TX
energy on to the Diode D3003 an HSU277 ( Pin Diode ) and from there on to
the ?front or rear Antenna select RL3015.
Other than that, there is another Diode D3005, that enjoys going bad and it
can also cause the problem you are having.
These are both on the bottom (B side) of the PCB. ?This diode turns on to
protect the RX when TXing. ?This is turned on from pin 4 on the Q3003.
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Hello and thank you for your response. I studied the schematic this morning and came to the same conclusion, it can only be D3003 or D3005. I located them on the layout and I have to remove the plate to see because of the interior side. I will tell you 73's SEB
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Hi the bad thing with mine was I had just got it from eBay, obviously the seller said it was in perfect condition, I could have sent it back, under eBays contract, but it was a good price with a tuner and lipo battery, I did leave him bad feedback, Let me how you get on with it, Dave 2E0DMB?
On Thu, 2 May 2024, 11:24 davebb123456 via , <davidbrowne76= [email protected]> wrote: Hi i found this when my FT817 did not output power on 2m and it was the Diode that had gone bad,
Good Luck, Dave 2E0DMB
so on Pin 8 of Q3003 on the PA Unit is a voltage called V-TX that
switches the output of the PA FINAL thru to the 2 Meter Low Pass Filter.
There it passes thru the Relay RL3001 which for 2Meter is closed from the
moving contact to the Normally Closed (Black) contact which passes the TX
energy on to the Diode D3003 an HSU277 ( Pin Diode ) and from there on to
the ?front or rear Antenna select RL3015.
Other than that, there is another Diode D3005, that enjoys going bad and it
can also cause the problem you are having.
These are both on the bottom (B side) of the PCB.? This diode turns on to
protect the RX when TXing.? This is turned on from pin 4 on the Q3003.
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On Thu, May 2, 2024 at 03:24 AM, davebb123456 wrote:
2E0DMB
Good evening 2E0DMB Well in the end it was D3003. I replaced it and it started again. To disassemble the PA board, it is better to first disassemble the main unit because there are pins connecting the two cards. For reassembly you must first dismantle the main unit, this is mandatory. (otherwise impossible to connect the pins) for the diode format it is SOT-323 I put a BAS316 in and it works great. 73's SEB F5SSL
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Great news, I fixed mine when I got the radio from a seller from eBay, like I said, he said it was working fine, but it wasn't, I had a old parts ft817 so I removed it from there, I am getting fed up getting things from eBay? And the seller's saying it was all working, Dave
On Thu, May 2, 2024 at 03:24 AM, davebb123456 wrote:
2E0DMB
Good evening 2E0DMB
Well in the end it was D3003. I replaced it and it started again.
To disassemble the PA board, it is better to first disassemble the main unit because there are pins connecting the two cards.
For reassembly you must first dismantle the main unit, this is mandatory. (otherwise impossible to connect the pins)
for the diode format it is SOT-323
I put a BAS316 in and it works great.
73's
SEB F5SSL
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yes this is often the case when buying second hand, lots of hidden defects..73's
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Yes but I still can't help myself trying to fix them instead of sending them back to the seller, All the best, Dave 2E0DMB?
yes this is often the case when buying second hand, lots of hidden defects..73's
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On 5/2/24 14:59, davebb123456 wrote:
I fixed mine when I got the radio from a seller
from eBay, like I said, he said it was working fine, but it
wasn't
You have a choice: take the chance or upgrade to currently produced
radio with decent factory parts availability.
I had a old parts ft817 so I removed it from there
If affordable, it's nice to have a parts department carcass or two
from which to liberate parts. I have a number of HW-8s serving in
that capacity.
I am getting fed up getting things from eBay And
the seller's saying it was all working,
Not to cover for unethical sellers, but modern day, 160M-70cm
mulit-mode rigs are complex little beasts - which makes thorough
check outs or spec verification challenging at best.
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Yes I know what?you mean, But when a radio has no power output on 2m ,I think the seller did know, Also sometimes you see things for sale ,and the seller said it is working as it?should as it lights up when powered up,
The last thing I got of eBay was a datong FL3 audio filter, and he said it worked Last time he used it years ago, it is very clean, yes it is 40+ years old, And guess what, it doesn't work, so I will fix this, Yes I did buy it as is, so I did leave feedback, I should have none, but I do like fixing electronics,? Dave 2E0DMB?
On 5/2/24 14:59, davebb123456 wrote:
I fixed mine when I got the radio from a seller
from eBay, like I said, he said it was working fine, but it
wasn't
You have a choice: take the chance or upgrade to currently produced
radio with decent factory parts availability.
I had a old parts ft817 so I removed it from there
If affordable, it's nice to have a parts department carcass or two
from which to liberate parts. I have a number of HW-8s serving in
that capacity.
I am getting fed up getting things from eBay And
the seller's saying it was all working,
Not to cover for unethical sellers, but modern day, 160M-70cm
mulit-mode rigs are complex little beasts - which makes thorough
check outs or spec verification challenging at best.
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I have a gen 1 FT-817.? Recently replaced the finals board (had very low power on TX all bands).? Incidentally the board is still available from Yaesu for $24.? P/N CB1333004.
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I thought I had the problems solved, however now I have discovered no TX power on 2M band.? Other bands are fine.? ?I plan to dig in the diode issue next.? Has anyone found a video or guide to assist with this repair?? I've looked around the web and not much out there for this specific issue.? ?Looking for any high res photos of the PCB and the diodes.? I understand need to get under the main PCB.? ? Thanks for any advice.
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Hi KA6BPV,?
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I posted a video a few months ago in response to a Youtube viewer who had no TX on 70cms. The 2m VHF and 70cms UHF TX paths are very closely related, so this 70cms video will help you understand the potential areas to look at for no TX on 2m. Here is my channel video: ?
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In this video, I review the schematic from the TX predrivers, PA finals and into the RF filtering to the antenna. Alas, most of the components will sit on the underside of the RF filter board, so you would need to pull the board out. And when out of the rig, there is no easy way to test the radio, so you will have to revert to basic diode testing of the diodes or transistors that could be affected, but this is straightforward with a multimeter diode test function: test the diode/transistor junctions wiht leads one way, then reverse the leads and retest. You can expect 0.7V(ish) in the conducting direction and 'OL' in the other. Anything else and it makes one suspect the diode/transistor is faulty.
?
Schematics are found on the internet - I use ? ?For an early FT817 (early LOT numbers), go to page 71 for the relevant schematic page, and p. 73/74 for the physical board layout drawings. There were some very modest changes in components in later versions (changes from resistors to inductors in the RX path for example), nothing significant in 2m troubleshooting. Look here to identify your LOT number as the schematics (different pages in the pdf above) to change:
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Before pulling the board out: confirm the rig RX on 2m with no issues - this helps narrow the issue to TX related control voltages, and RF TX path switching via relays. If there also no RX on 2m, the issue could also then be in the LPF and HPF circuits with an open or short/low impedance path to ground.
?
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Good luck and let us know how it goes.
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73 de Matt, M0NJX
Westerham, Kent, England.
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Hello from the UK.
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I have a gen 1 FT817 that I still love.?
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I have just had your problem and it was fixed by Yaesu here in the UK - they take 3 to 4 weeks to repair and always do a fantastic job.
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Basically I blew the front end a couple of years back and Yaesu replaced the PA board with the new rugged version.
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I then lost the power output on 2m a few months back, like you are experiencing.
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Karl, head of tech.sales at Yaesu UK, diagnosed the fault over the telephone as I was transmitting on all other bands and still had receive on 2m, but extremely low output.
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If it helps you, there was a faulty switching relay and diode that are used to switch between the VHF and UHF section … the service note from the Yaesu service engineer says “replace Relay RL3001 & Diode D3003 on PA Unit”
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I hope this helps!!
Neil Bundle, G4LRV
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Dorset, England
DT10 1HQ
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Hi Neil
What did they charge for the repair,
Dave 2E0DMB
Hello from the UK.
?
I have a gen 1 FT817 that I still love.?
?
I have just had your problem and it was fixed by Yaesu here in the UK - they take 3 to 4 weeks to repair and always do a fantastic job.
?
Basically I blew the front end a couple of years back and Yaesu replaced the PA board with the new rugged version.
?
I then lost the power output on 2m a few months back, like you are experiencing.
?
Karl, head of tech.sales at Yaesu UK, diagnosed the fault over the telephone as I was transmitting on all other bands and still had receive on 2m, but extremely low output.
?
If it helps you, there was a faulty switching relay and diode that are used to switch between the VHF and UHF section … the service note from the Yaesu service engineer says “replace Relay RL3001 & Diode D3003 on PA Unit”
?
I hope this helps!!
Neil Bundle, G4LRV
?
Dorset, England
DT10 1HQ
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Hello Dave 2EODMB
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About ?132 - ?90 labour (1.5 hrs) plus ?4.60 for relay plus diode, plus VAT plus ?15 carriage.
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It’s fiddly stuff !
I’m happy … your call …
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Neil
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Hi Neil
Thanks for the info,
Yes it is a big job, but I have done a lot of smd work so I changed the diode myself,
Good luck
Dave 2E0DMB
Hello Dave 2EODMB
?
About ?132 - ?90 labour (1.5 hrs) plus ?4.60 for relay plus diode, plus VAT plus ?15 carriage.
?
It’s fiddly stuff !
I’m happy … your call …
?
Neil
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Thanks Dave … I never had the opportunity or training for SMD work … well done!
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Thank you very much. Here the same, but a couple of hours after turning it on, the power goes back to normal.?
I'm not sure I want to spend 130� for the 2m band only... I'm thinking about a heater? ;-)
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Pietro I2OIM
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Seb5347
Jeff WN1MB
Pietro Molina