G4BLL,
What is the part number for the transistor in the FT817/8's PA.? I'd like to get some.
I like dealing with Digi-Key for they do sell what they list, actual manufacture's parts.
73, ron, n9ee/r Ron Wright, N9EE/R Hernando Co ARES EC
Spring Hill, Florida also n9ee55@...
On Monday, August 12, 2024 at 01:27:39 PM EDT, Ken N2VIP <ken@...> wrote:
Peter,
Pretty much everything you've said is correct, I think you've got a good handle on the situation, BUT I want to point out that our discussions so far have been about Yaesu America, your distributor may have stock in repair boards and may even still be repairing FT-817s. I'd encourage you to contact Yaesu near you and enquirer- you may get lucky and your FT-817 may get a reprieve and get a new set of finals!
Good luck, Ken, N2VIP On Aug 12, 2024, at 11:57?AM, Peter Burnett via groups.io <g4bll.peter@...> wrote:
?
Thanks for your input Ron.? There has been a lot of useful stuff posted on this issue, some of it confusing (to me) and some contradictory.? I wanted to ensure that my 818 was in no immediate danger but should I invest in some replacement output transistors as insurance for the future. This would appear to be a sensible course of action. However, one contributor quite rightly pointed out that there are a lot of inferior Chinese copies flooding the market place. Another contributor suggested a source of supply where it was reasonably certain they would be genuine. Hmm! The second conundrum is it going to be worthwhile to try and get my old 817 back up and running on tx, or just be content to use it as rx only. Is it really going to be a practical proposition anyway? The general consensus is that the 818 board can be “shoehorned” into the elderly 817s, but there aren’t any available and Yaesu can’t advise a delivery date or are not interested ( my interpretation). Another suggestion was to find a company/person willing to produce a short run copy, buy the output transistors and populate the rest of the board as required. I don’t mind admitting this is a non starter for me unless I can find someone in the UK to do the job for me. It is starting to sound like an expensive exercise.? I think the sensible thing at this stage is to sit tight, see if, in fact, the 818 boards become available from Yaesu and someone does succeed in grafting it into a dead 817.? Hope my interpretation reflects the current state of play.? G4BLL On 12 Aug 2024, at 01:13, Ron Wright via groups.io <lt_wright_flg@...> wrote:
? The problem was not the internal battery running down to 0 volts, but rather like running down to around 5V or some low voltage.? The PA in the 817 and 818 are wired directly to the power input or internal battery all the time and are not switched with the ON/OFF switch.? Most rigs are wired this way.
What would happen at the low out of spec voltage the PA would start to self oscillate on it's own and kill itself.? I am sure this happen to my FT817 when I had stored it with rechargeable batteries, after 6 months turned the rig on and the PA was dead.?
When replacing the PA it was advised to reverse the input and output RF coax connections to help prevent this.
But I had understood Yaesu in their new redesign f the PA in the mid to late life of the 817 supposedly corrected the oscillation issue, but I also understand Yaesu never admitted it happening.? There were some who took variable power supplies and did verify the PA would self oscillate on it's own.
73, ron, n9ee/r Ron Wright, N9EE/R Hernando Co ARES EC
Spring Hill, Florida also n9ee55@...
On Sunday, August 11, 2024 at 03:30:06 PM EDT, Peter Burnett via groups.io <g4bll.peter@...> wrote:
Thanks Ken.? On 11 Aug 2024, at 20:14, Ken N2VIP <ken@...> wrote:
?
The self-destruct finals feature is unique to the original, non-nd, FT-817. Your FT-818 should be fine, but I'd suggest pulling batteries out of the unit if you plan on storing it for an extended period, similar to almost any battery-powered device. Ken, N2VIP On Aug 11, 2024, at 13:57, Peter Burnett via groups.io <g4bll.peter@...> wrote:
? I have an 817 (ser. No; 1D) no rf output and an 818 ( ser. no; 8J) still healthy.?
Do I understand correctly that my 818 will not self destruct if I forget to charge it and the internal battery runs down to zero volts?
Peter G4BLL
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Peter Burnett G4BLL
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Peter Burnett G4BLL
-- Peter Burnett G4BLL
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