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Final board version

 

I recently replaced the final board in a hamfest special. I have read about some versions with finals oscillating and destroying them with low internal battery voltage. Is there a version of board with a fix for this? How to identify it? The radio came with two battery packs. I may just keep using the external battery.
73 John N4HNO?
 

Hi John and the group,

I have never used the internal battery for this exact reason, only external PS and my 817 is from the pre lot 45 so very very early production, this has original finals..I bought it new in 2001 from radio world in Toronto.
Best regards and enjoy that 817, they are incredible little radios!
Rick VE1RNM?

On Tue, May 20, 2025, 11:01 a.m. Tech Guy via <tech48055=[email protected]> wrote:
I recently replaced the final board in a hamfest special. I have read about some versions with finals oscillating and destroying them with low internal battery voltage. Is there a version of board with a fix for this? How to identify it? The radio came with two battery packs. I may just keep using the external battery.
73 John N4HNO?
 

I believe the original FT817 is subject to this problem, but it was repaired in the FT817ND. The best way to tell if you have an 817ND is by the choice of backlight colors for the display. I think the original FT817 only had two color choices, and the ND has more. I have never had any problems with my FT817ND.

Zack W9SZ

Virus-free.


On Tue, May 20, 2025 at 9:01?AM Tech Guy via <tech48055=[email protected]> wrote:
I recently replaced the final board in a hamfest special. I have read about some versions with finals oscillating and destroying them with low internal battery voltage. Is there a version of board with a fix for this? How to identify it? The radio came with two battery packs. I may just keep using the external battery.
73 John N4HNO?
 

I should have said it was a 817 not nd. I meant was the fix on the replacement board. My gel cells are working ok. I will just stick to those.
73 John
 

It was over 10 years ago when Yaesu went with the newer PA board, claimed changed due to transistors on old board were no long made.? Yaesu never admitted to the oscillation issue.

I am sure the PA board you have is the newer version.

One thing to prevent the oscillation was to reverse the coax input and output cables of the PA board.

There is in FILES instruction and info on the PA board replacement.

73, ron, n9ee/r

Ron Wright, N9EE/R
Hernando Co ARES EC
Spring Hill, Florida also n9ee55@...


On Tuesday, May 20, 2025 at 12:09:16 PM EDT, Tech Guy via groups.io <tech48055@...> wrote:


I should have said it was a 817 not nd. I meant was the fix on the replacement board. My gel cells are working ok. I will just stick to those.
73 John
 

The earliest '817's had no fuses, but got a 3.15A battery fuse (F1001) for the second revision.
ND's got a second 2.3A "protector", F1002, for the 13V lines going down to the PA board.
This might also prevent destruction of the PA transistors when it goes unstable.
F1002 in my ND has gone in the past.
I would probably add it if I had an '817 I was fixing.

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