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Interesting observation concerning crystals...

 

My sickness concerning old vintage radios had morphed into revisiting the CB radios I messed with when I was a young 'un.? I have noticed that several have had one or more crystals out, which in a synthesized radio one crystal is likely to take out 4 or more channels.? During my beating on these old relics I decided to put a DDS signal generator across the crystal, dial in it's frequency, and verify the "lost" channels were now there and usable.? All worked as I expected except when I unhooked the signal generator the channel was still functional!? Sometimes it would stop working when I switched back and forth to a channel not on the crystal, sometimes not.? The latest I tried was a Realistic TRC-47 which is a 23 ch SSB rig and it had one crystal "dead."? I hooked up the SG and brought the group of channels back to life and unhooked the SG.? All channels were still alive and remained that way for the rest of the day!? I'll see tomorrow if they still work when I turn it on.
?
Can someone explain this behavior?? It's almost like "goosing" the tired crystal "repaired" it, or something.? After I get finished playing with these old CBs I'm going to pull a Heathkit receiver off the shelf that has a couple bad crystals and see if it will wake them up.
?
73,
--
Justin B.
KI5GKD
 

If I understand this the crystals are physically present but have
not been working. Yes, it is possible that hitting them with drive from
a signal generator may have awakened them. I would suggest that you try
baking all the "dead" crystals. Someone will correct me but I think the
temperature is around 350F for a few hours. This will sometimes wake up
dead crystals and also move drifted crystals back to their original
frequencies. Reports are that it works much of the time. The reason is
not certain but it seems to clean deposits off the surface or, perhaps
renew aged plating or soldering. Whatever is the explanation it seems to
work. It is possible that driving the crystals hard with an external
signal may accomplish a similar effect.


On 3/11/2025 10:31 PM, Justin Bowser - KI5GKD wrote:
My sickness concerning old vintage radios had morphed into revisiting
the CB radios I messed with when I was a young 'un.? I have noticed that
several have had one or more crystals out, which in a synthesized radio
one crystal is likely to take out 4 or more channels.? During my beating
on these old relics I decided to put a DDS signal generator across the
crystal, dial in it's frequency, and verify the "lost" channels were now
there and usable.? All worked as I expected except when I unhooked the
signal generator the channel was still functional!? Sometimes it would
stop working when I switched back and forth to a channel not on the
crystal, sometimes not.? The latest I tried was a Realistic TRC-47 which
is a 23 ch SSB rig and it had one crystal "dead."? I hooked up the SG
and brought the group of channels back to life and unhooked the SG.? All
channels were still alive and remained that way for the rest of the
day!? I'll see tomorrow if they still work when I turn it on.
Can someone explain this behavior?? It's almost like "goosing" the tired
crystal "repaired" it, or something.? After I get finished playing with
these old CBs I'm going to pull a Heathkit receiver off the shelf that
has a couple bad crystals and see if it will wake them up.
73,
--
Justin B.
KI5GKD
--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998
 

What I run into more than anything else are drifted crystals, which can play havoc in circuits such as band-switched heterodyne oscillators and seriously affect dial accuracy.? I haven't tried the method you mentioned for trying to revive a dead crystal, but will give it a shot sometime!
?
73 - Steve, KW4H
 

Richard - I tried that on a heathkit SB-301 and baking woke up 2 crystals.? I just got back in from the shop re-testing the TRC-47 and that crystal is still working! :-)? The Comstat 25 originally had three crystals dead and today only one so I guess that's progress.? If the one stays dead I might replace it with a ProgRock 2...
?
73,
--
Justin B.
KI5GKD
 

Justin -- I keep a good stock of those ProgRock2's, if you decide to go that route I can pop one into the mail to you cheaper than you ordering one from Turkey (and certainly much faster).
?
73 - Steve, KW4H
 

This package looks great and less expensive than ordering a crystal not to mention the reduced lead time. I opened the QRP Labs manual for this devise and had trouble with programming it for a specific frequency. It looks ideal to fit in a HC6/U but for a non computer savvy old timer, the programming of this devise to a specific frequency is a mystery.
 
Edited

Thomas,
?
I wrote an article last year called "Programmable Crystals to the Rescue", which was published in the March/April 2024 edition of ER Magazine.? That article describes in great detail how a ProgRock2 was integrated into a Heathkit HR-1680 and exactly how to program the device.? If you have access to that article, a lot of your questions will be answered.? Otherwise, I'd be happy to answer them here.? I still use the ProgRock2 for my projects when needed, and have also designed an interface board that makes it easier to integrate.
?
73 - Steve, KW4H
Tucson, AZ
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?
?
On Friday, March 14th, 2025 at 6:29 AM, Tom Smith <n5ama@...> wrote:

This package looks great and less expensive than ordering a crystal not to mention the reduced lead time. I opened the QRP Labs manual for this devise and had trouble with programming it for a specific frequency. It looks ideal to fit in a HC6/U but for a non computer savvy old timer, the programming of this devise to a specific frequency is a mystery.
 

Hi Steve,
Thanks for the quick reply and the offer to help. I have a complete collection of the ER magazines (have had a subscription since ER#8) and enjoy it more than any magazine I receive. I will certainly look up your article and if it looks like I can manage to program one of these devices, I will certainly order several. I’m replacing crystals in a Beckman 905 receiver that receives WWV signals from 2.5-25mhz.
?
Thanks again,
Tom N5AMA
 

Tom,

I keep a fairly large stock of the ProgRock2's -- if you need some and don't want to wait for delivery from Turkey, just let me know -- you can buy them from me at the same price listed on the QRP Labs website.? I'm not officially a reseller, but ordered a bunch for use with the interface boards I designed and for other fun projects.

One thing to keep in mind about the ProgRock2 is that although it's advertised as a "programmable crystal", it's not exactly a drop-in replacement.? The ProgRock2 is, in actuality, a programmable oscillator that outputs a 3v P-P square wave, driven by a Si5351a.? In fact, you can simulate the use of a ProgRock2 by using a function generator at the frequency you're looking for, and set it for a square wave at 3v P-P.? The trick is to figure out how to integrate it in a vintage circuit.

73 - Steve, KW4H

On Friday, March 14th, 2025 at 8:08 AM, Tom Smith <n5ama@...> wrote:

Hi Steve,
Thanks for the quick reply and the offer to help. I have a complete collection of the ER magazines (have had a subscription since ER#8) and enjoy it more than any magazine I receive. I will certainly look up your article and if it looks like I can manage to program one of these devices, I will certainly order several. I’m replacing crystals in a Beckman 905 receiver that receives WWV signals from 2.5-25mhz.
?
Thanks again,
Tom N5AMA
 

Steve - I don't subscribe to ER so would it be possible to e-mail me a copy of your article or post it here?
?
73,
--
Justin B.
KI5GKD
 

Oh, I received and SB-303 last year that had a lot of dead crystals so replaced them all with an Arduino andsi5351 module...
?
/g/heathkit/message/7651
--
Justin B.
KI5GKD
 

Justin - you did the right thing in that SB-303.? The number of frequencies that can be readily switched with the ProgRock2 is a maximum of eight.? Technically it can output 24 pre-programmed frequencies (3 banks of 8 frequencies each), but switching the bank output when using the device to replace a heterodyne oscillator section where more than 8 crystals are involved is so difficult, it's best to just use the Arduino.? I did the same in a SB-313.

73 - Steve, KW4H

On Friday, March 14th, 2025 at 9:55 AM, Justin Bowser - KI5GKD <justin.bowser@...> wrote:

Oh, I received and SB-303 last year that had a lot of dead crystals so replaced them all with an Arduino andsi5351 module...
?
/g/heathkit/message/7651
--
Justin B.
KI5GKD
 

Steve, that sounds great. I’m not sure how the Beckman will respond to a square wave but it’s certainly worth a try. I would like to buy 3 of them. What is your preferred payment method and what shipping costs do I need to include to Texas (77429)?
?
Thanks,
Tom N5AMA
 

The ProgRock2's are $18 each (same as the QRP Labs site), and shipping is $5 (total).? I ship stuff in little boxes, rather than padded envelopes, which raises the cost a little but nothing arrives smashed by post office processing equipment.? Total is $59.

Is the shipping address correct on QRZ?? I'm good on QRZ as well.? Just a check in the mail is preferred, and I will send this out right away.??

If anyone else ever needs ProgRock2's, I have a plentiful stock -- no need to order from Turkey.

73 - Steve, KW4H
On Friday, March 14th, 2025 at 3:39 PM, Tom Smith <n5ama@...> wrote:

Steve, that sounds great. I’m not sure how the Beckman will respond to a square wave but it’s certainly worth a try. I would like to buy 3 of them. What is your preferred payment method and what shipping costs do I need to include to Texas (77429)?
?
Thanks,
Tom N5AMA
 

Hi Steve,
I’ll put a check in the mail to you tomorrow for three of them. Thanks for making them available.
?
Tom N5AMA
 

All boxed up and ready to go out in the mail tomorrow.? You'll get a notice from my Pirateship account.

73 - Steve, KW4H

On Saturday, March 15th, 2025 at 9:58 PM, Tom Smith <n5ama@...> wrote:

Hi Steve,
I’ll put a check in the mail to you tomorrow for three of them. Thanks for making them available.
?
Tom N5AMA

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