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Vintage Amateur and Military Radio Amateur/military receivers and transmitters, morse, and any other related vintage comms equipment.

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Old 20th Oct 2021, 12:32 am   #21
Vecher1
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Default Re: Regency Range Gain CB

OK Here are some links

https://live.staticflickr.com/65535/...feb0dc74_k.jpg

https://live.staticflickr.com/65535/...82e98e5e_k.jpg

https://live.staticflickr.com/65535/...508f1d78_k.jpg

https://live.staticflickr.com/65535/...7cc40a32_k.jpg

https://live.staticflickr.com/65535/...7fcbaf2e_k.jpg


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Old 20th Oct 2021, 4:28 am   #22
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Default Re: Regency Range Gain CB

UPDATE: I put a fan on top of radio right over the xtals .. was able to get it working for over 1 hour with no problems.. so definitely a heat problem

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Old 20th Oct 2021, 5:50 am   #23
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Default Re: Regency Range Gain CB

Thanks for the pictures,very interesting to see.
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Old 20th Oct 2021, 7:33 am   #24
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Default Re: Regency Range Gain CB

It wasn't unreasonable of them to want to know specs, because there is more to a crystal than just the resonant frequency. If the specs are not known then the provider can usually analyse a similar crystal from the set - one of the other 8xxx crystals in this case, if you are prepared to loan them one for the duration. Or, if you furnish them with the circuit diagram of the set they can sometimes work the details out from that.

If this was something like a walkie-talkie which people might commonly want crystals for alternative channels made for, the supplier would most likely already know the spec and have it on file, having made some before.

There is at least one UK active supplier of bespoke one-off crystals, Quartslab (note the spelling, with 's', is correct). I don't know if it will be cost effective for you to use them when international carriage etc is taken into account.
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Old 20th Oct 2021, 8:22 am   #25
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Default Re: Regency Range Gain CB

Just saw the pictures - what a nice example. Well worth getting back into full working order at any reasonable cost, I would say.

I forgot to mention - the parts list may include the spec (capacitance, etc) in the description of the crystals. Our locked-down works IT won't let me visit the site to look at it just now.
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Old 20th Oct 2021, 4:10 pm   #26
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Default Re: Regency Range Gain CB

Just had a look at it now - unfortunately no detail except for the frequencies in that parts list.

Reply #23 in this thread...

https://www.eevblog.com/forum/repair...uency-crystal/

...over on eeblog.com has a short list of possible bespoke crystal makers, most are in the USA and one even in Pennsylvania (although I realise Pennsylvania is a big place). Maybe you could try your luck there?
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Old 20th Oct 2021, 5:56 pm   #27
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Default Re: Regency Range Gain CB

Is this a crystal suffering sleeping sickness? It won't go or it starts but then later fades.

David RW referred to the problem of soldered crystals having reducing activity due to flux migrating from the joints to the plate and being loading down with goo.

Opening them up, cleaning and resoldering has a tendency to make even more flux and it's a bit of a roulette game. There is another way I have known to work. Might be worth a try first or before having something made.

You can apply some RF to the crystal at the resonant frequency and shake things up a bit. I did it with an HF sig gen with decent fine tuning (you need to hit the resonance which will be very narrow).

Take the 50 Ohms out lead and put a 10 Ohm resistor in series with the hot pin, connect that to one crystal pin and the other crystal pin to ground.
Connect an HF oscilloscope scope straight across the crystal pins.

While tuned somewhere near the crystal frequency apply 0dBm out from the generator. Adjust the scope so you can see the RF waveform at a decent level on the screen, maybe 8 divisions pk-pk? Now slowly tune the generator across the crystal frequency. At some point you should find a sharp dip. (This might not be at the marked frequency because you have a scope connected in parallel which messes up the loading)

Keep the generator tuned in the minimum since here the crystal is absorbing power and getting a good work out. Give it 10 minutes or so.

I have known this to wake up sleepers. Use more SG power if you dare on stubborn cases. Your crystals are HC6/U so they should take some shove.
The series 10 Ohms should give them some protection too.

PS - what is it about the first oscillator in that Regency schematic which seems to have no intended feedback path?
At least the second valve, which seems to be an oscillator mixer, has a bit of a Colpitts about it.

PPS - I love this set!
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Old 20th Oct 2021, 6:55 pm   #28
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Default Re: Regency Range Gain CB

This is turning into a great thread - I've never heard of trying to 'exercise' a lazy crystal before.
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Old 20th Oct 2021, 8:53 pm   #29
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Default Re: Regency Range Gain CB

Me Either.. Never tried that..

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Old 21st Oct 2021, 1:05 am   #30
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Default Re: Regency Range Gain CB

Here is the osc circuit..

https://live.staticflickr.com/65535/...4d8d7e0a_c.jpg

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Old 21st Oct 2021, 7:34 am   #31
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Default Re: Regency Range Gain CB

Yes thats the same as I was looking at.
Here is what I was referring to in Post #27.
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Old 31st Oct 2021, 8:48 am   #32
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Default Re: Regency Range Gain CB

10 days and no update?
I'm still curious about the first osc.
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Old 31st Oct 2021, 8:57 am   #33
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Default Re: Regency Range Gain CB

I think the OP has good reason to believe that the crystal is the sole cause of his fault, so he will either try your wake-up recipe or try to get a replacement made.

Unfortunately there's no law which states that anyone has to keep us informed of the outcome of a case, as much as we all love to see a happy ending.

The OP and I have something in common, I suspect: We can't explain why that first oscillator works. Maybe if you post that circuit fragment in 'Components and Circuits' someone will have some idea? Not everyone reads CB related threads.
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Old 31st Oct 2021, 2:05 pm   #34
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Default Re: Regency Range Gain CB

Quote:
We can't explain why that first oscillator works
The "hidden" capacitive coupling twixt anode and grid, the crystal does the phase shift to make it oscillate.
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Old 31st Oct 2021, 5:31 pm   #35
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Default Re: Regency Range Gain CB

Ha, I'm rumbled. It was curiosity about the oscillator really although I will be very pleased to hear more news from the OP!

Now wondering whether some deliberate extra pF between Anode to Grid would help it out. It might actually go on the sleepy one then, though of course it could pull the frequency a little.
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Old 31st Oct 2021, 5:40 pm   #36
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Default Re: Regency Range Gain CB

The oscillator for the 8.xxx crystals is actually the right hand one, the one you don't seem to have concerns about.
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Old 1st Nov 2021, 12:11 am   #37
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Default Re: Regency Range Gain CB

Ok Follow up: After putting the fan on top to help cool down the crystals I have had no problems..I am sure its the crystal however since this is not mine and it belongs to the Antique store I fix radios for.. He doesn't want to spend any extra money on trying to get a crystal..

If it was mine then I would order a crystal..

So for now its back to the store.. He may keep it for himself or sell it..

Thanks to all for your input to this problem . I can rely on you guys (and gals) to help with problems like this

Thanks

Again

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Old 1st Nov 2021, 12:20 am   #38
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Default Re: Regency Range Gain CB

Thanks for the conclusion Skip - doesn't sound to me as though it will get fixed, which is a shame.

There are a small group of us here who are always interested in looking at vintage CB equipment, although I'm certain that yours is the earliest model ever to feature here. Normally, we're looking at 70s-80s era (transistorised / PLL synthesised) equipment, so that set was something quite special.
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Old 2nd Nov 2021, 3:35 am   #39
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Default Re: Regency Range Gain CB

Understand.. I am old school only work on tube (valve) radios.. Tx and Receivers..

Thanks to all for the great help.. I will be back as soon as I get another radio to repair.

Skip WB4YVO

PS I just recency repaired a UK RAP635 Radio It was fun.. It is mine.. Never saw one over here in states..

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Old 6th Nov 2021, 9:26 pm   #40
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Default Re: Regency Range Gain CB

Just a thought could you use one of the epson programable oscillators,as used in the clansman prc-320 lsb conversions?
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