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Where to get an HSU277??

I have never had good luck contacting Yaesu support.? I was calling during COVID, so that might have been the issue. They might have some.

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The HSU277 is very tiny, and I suspect that most people without SMD equipment and experience need two or three to finally do it correctly. In the case of D3003, the PA board needs to be removed to get at it, so the service person can position it under a magnifier. The advantage of a component replacement is that no alignment of a new board should be needed (with very careful handling). Good practice indicates a realignment when an RF board with tunable components is removed and replaced.?

There are a few suppliers that are reputable, like LittleDiode, that want about 12 Euro each for individual items. There might be reasonably equivalent PIN diodes that aren't SMD, or a different SMD form factor with similar specs, that could be retrofitted.? It's VHF, so the signal path needs to be short. I haven't looked into it. I have a couple 30-year-old VHF amps that use standard PIN diodes, so they're around.?

I have ordered a package of HSU277s from AliExpress for about $10, hoping that they are real--or real enough. EBay has some "refurbished" items for about $10 each. I think "refurbished" means scavenged from boards. I have not had good luck in general with parts from these sources. There are lots of counterfeits that will test OK and operate well enough if they are not pushed very hard. In this case, you're putting 5 watts through the part, so you're at the edge of its capability.?

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Jim