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It is currently 26 Jan 2021, 23:39

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PostPosted: 04 Feb 2018, 14:28 
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Joined: 08 Aug 2009, 03:11
Posts: 2229
Location: Chilliwack, BC
Hi Folks,

Got a tuner here I believe the LC7207 is shot, but am hoping for an alternative to handing it back declared a boat anchor.

It came in with "manual" working OK, along with the FM memories, but no AM memory.

I replaced the rechargeable batteries (yes, they're good) and recapped it. Same problem.

I let it run for a few days, turned it off, then on... now no memories worked, but manual was fine.

Put it on the back burner for a bit (still running to keep the batteries chareged), but then upon switching from AM to FM again, FM locked up at 189.3 MHz and won't budge. No manual, no nothing.

I can even unplug all but the power wired to the board and it's locked at 189.3. I'd expect it to show zero when I did that as the frequency counter gets no input.

So, given it's a stupid P-MOS with unprotected gates (full ESD protocols were in place at the bench), I'm assuming it's the aforementioned unicorn-7207 :confused:

After much Googling, seems this happened only one other time, but everyone was stuck on changing the batteries (which he did, to no avail).


-= Gregg =-
* Ratings are for transistors - tubes have guidelines*
Home: GeeK ZonE
Work: Classic Valve Design

PostPosted: 03 Aug 2018, 09:54 
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Joined: 05 Aug 2016, 14:35
Posts: 227
Why? The LC7207 is cheap enough and readily available. If you are sure that is what it is, get one, pop it in and see what you get?

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