I am curious too.? Old crystals are not hermetically sealed and it looks like it would? just
un-screw.? If it was mine I would take it apart.? The old FT-243 crystals were like that and
the crystal was sort of held by a few points around the edge.? Maybe corrosion or something?
Crystals should be very stable.? Back in the day, my SX-110 worked fine.
73,
Gary
WB6OGD
On 11/02/2022 4:54 PM don Root <drootofallevil@...> wrote:
Steve ¡ doing the same thing in the test setup or in the receiver or both?
I am a curious reader at this time
Don VA3DRL
?
Yeah, I ordered a couple of 455 KHz crystals today.? It would be good to have another on hand.?
FYI, I stumble onto these things because I restore boat anchors (mostly receivers) for educational and historical purposes.? I also write articles for ER magazine, and the extra information is fun and interesting.? Anyway, I¡¯m more likely to remove a component and test it out of curiosity rather than questioning the design.? The unstable crystal caught me by surprise! ?And just for the heck of it, I pulled a similar crystal out of a SX-71 awaiting restoration and it¡¯s doing exactly the same thing.? Still mulling that over.
73 ¨C Steve, KW4H
I've owned several SX-110's over the years, including the one I used as a Novice back in '67, that was like new I acquired from original owner. Never had any issues with xtal instability. They all were fairly stable after initial 10-15 min. warmup. Sounds like you need a new xtal.
In a message dated 11/2/2022 1:23:14 PM Eastern Standard Time, reedsteve@... writes:
Sent from Proton Mail for iOS
On Wed, Nov 2, 2022 at 10:20 AM, Richard Knoppow <1oldlens1@...> wrote:
I am not an expert but think this is not normal.? ?It looks like the crystal holder comes apart.? ?Perhaps cleaning crystal and electrodes will fix it.
-------- Original message --------
From: "KW4H via groups.io" <reedsteve@...>
Date: 11/2/22 9:28 AM (GMT-08:00)
Subject: [HallicraftersRadios] SX-110 Crystal Instability
Attached is a photo of the crystal in my SX-110.? I pulled the crystal to test its resonant frequency using a sig gen and scope, and the darn thing is so unstable it¡¯s driving me loopy.? The resonant frequency can vary (roughly) between 453.700 KHz and 453.800 KHz by simply moving it around, no matter how gently.? Pardon my ignorance, but is that normal for crystals of this vintage?? Is there a reason, operationally in the Hallicrafters, for a crystal to act like this?? Before I order a different (and more stable) crystal to solder into the circuit, thought I should ask.
73 ¨C Steve, KW4H
