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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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16th Oct 2021, 4:49 am | #1 |
Triode
Join Date: Apr 2021
Location: Lansdale, Pennslyvania, USA
Posts: 46
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Regency Range Gain CB
ALL, unique problem.. radio recapped. working great with good rx and tx.. then after about 1/2 hour or so..channels of 4,8,12,16,20, and 23 kind of stopped working... but not really .. signal via signal generator went from s7 down to about s3.. also tx power went went down.. all other channels are ok.. only thing common to all those channels is a 8.533 mhz xtal.
can a xtal heat up and stop working somewhat? very baffled with this one i can post a schematic if needed.. hope this is the right place to put this Skip |
16th Oct 2021, 8:47 am | #2 |
Dekatron
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
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Re: Regency Range Gain CB
Hello Skip,
From the sound of it broadly speaking there will be similar crystals doing the same job for other groups of channels like:- 2,5,9,13... etc 3,6,10,14...etc Try swapping your suspect crystal with one of those others. Obviously the two blocks of frequencies will swap over, but the point is to see whether the fault moves with the crystal or stays where it is. You must be using one signal generator as your test signal source - if you have a second (synthesised?) generator with rock steady output you could remove the suspect crystal temporarily and inject 8.533MHz from that alternative source to see if that 'fixes' the problem. Edit: For the avoidance of doubt, this sounds like an interesting early multi-crystalled 23 channel AM set which is legal to use where Skip is, in the USA. Last edited by SiriusHardware; 16th Oct 2021 at 8:53 am. |
16th Oct 2021, 2:46 pm | #3 |
Triode
Join Date: Apr 2021
Location: Lansdale, Pennslyvania, USA
Posts: 46
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Re: Regency Range Gain CB
Ok thanks Xtals are soldered in place kind of hard to get to but not impossible..
I will fire it up this morning to see if it starts working again.. if so how long it does work.. And yes its a 23 channel older CB set used in the US Fixing for a friend Thanks Skip |
16th Oct 2021, 8:34 pm | #4 |
Dekatron
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
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Re: Regency Range Gain CB
Do you have some freezer spray available? Turn the set on, let it warm up until the fault comes on and then try cooling the crystal.
I would be interested in seeing a photo or two of the outside and inside of this set - by the time CB arrived in the UK the sets were typically only using three crystals or one crystal so we didn't see many sets like that over here. Also, if you have a link to an online copy of the schematic that would be interesting to see and would make it easier for us to follow your progress. Last edited by SiriusHardware; 16th Oct 2021 at 8:40 pm. |
17th Oct 2021, 2:04 am | #5 |
Triode
Join Date: Apr 2021
Location: Lansdale, Pennslyvania, USA
Posts: 46
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Re: Regency Range Gain CB
Sure I will take some pictures and post schematic.
Skip |
17th Oct 2021, 4:40 am | #6 |
Moderator
Join Date: Mar 2012
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Re: Regency Range Gain CB
Yes.
Cheap crystals usually were mounted in cans that were soldered together, and inside there would be a little solder on the wires connecting the electrodes on the quartz to the holder pins. I have in the past opened dud crystals and sometimes found dry joints inside. Re-touching them and cleaning worked, but there was a small shift in frequency. Excessive operating amplitude can also sometimes shatter crystals. Once you've tried moving things around to verify it's the crystal which is iffy, then you have nothing to lose by opening it. I'm assuming it's a soldered HC6 series case. Look out for a plob of solder elsewhere on the case blocking a vent hole used during assembly. Open the hole before soldering the case back together, let the unit cool, then quickly blob over the hole to reseal the case. David
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17th Oct 2021, 9:55 am | #7 |
Dekatron
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
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Re: Regency Range Gain CB
I went on a pre-emptive search for information and wow, this is not only an early CB set but a valve (...tube) set, complete with a vibrator to enable the set to run from low voltage - if I'm looking at the right one.
http://www.oldtuberadio.com/data/Reg...5_p124-133.pdf Last edited by SiriusHardware; 17th Oct 2021 at 10:06 am. |
17th Oct 2021, 10:46 am | #8 |
Dekatron
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Location: Newcastle, Tyne and Wear, UK.
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Re: Regency Range Gain CB
Just been looking at the diagram linked to above and the crystal associated with channels 4,8,12,16,20,23 has a frequency of 8.655MHz rather than 8.533MHz according to that information, so maybe I haven't got the right diagram?
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17th Oct 2021, 11:18 am | #9 | |
Nonode
Join Date: Oct 2010
Location: Gloucester, Glos. UK.
Posts: 2,149
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Re: Regency Range Gain CB
Quote:
Would be good to see a proper picture of yours with the innards if possible.
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17th Oct 2021, 9:46 pm | #10 |
Triode
Join Date: Apr 2021
Location: Lansdale, Pennslyvania, USA
Posts: 46
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Re: Regency Range Gain CB
Miss typed its 8.655 mhz
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17th Oct 2021, 9:47 pm | #11 |
Triode
Join Date: Apr 2021
Location: Lansdale, Pennslyvania, USA
Posts: 46
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Re: Regency Range Gain CB
Taking some pictures Will post then soon
Skip |
18th Oct 2021, 6:35 pm | #12 |
Dekatron
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Location: Newcastle, Tyne and Wear, UK.
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Re: Regency Range Gain CB
While waiting for those images I sat down and wrote a short program which shows how the combinations of crystals generate the (then) 23 channels of the USA CB system. The additional channels 24-40 weren't added until about 1977, or so I understand.
Each position on the channel select switch selects a pair of crystals whose frequencies are summed together for a frequency which is equal to the desired channel frequency minus 7.5Mhz. This summed frequency is used in receive mode as the input to the receiver first mixer (the receiver first I.F. is 7.5MHz). In transmit mode the summed frequencies of the two crystals are further mixed with a 7.5MHz oscillator to produce the 27MHz TX frequencies. This table shows how it normally looks - note the occasional 20Khz jumps and the large leap to the last frequency are correct - the jumps between channels 3-4, 7-8, 11-12, 15-16, and 19-20 were to step over already pre-existing radio control channel frequencies. The historic reason for the giant leap from 27.225 (Channel 22) to 27.255 (Channel 23) is less clear. Code:
CH X1 X2 Sum I.F. Freq 01 8615 10850 19465 7500 26965 02 8625 10850 19475 7500 26975 03 8635 10850 19485 7500 26985 04 8655 10850 19505 7500 27005 05 8615 10900 19515 7500 27015 06 8625 10900 19525 7500 27025 07 8635 10900 19535 7500 27035 08 8655 10900 19555 7500 27055 09 8615 10950 19565 7500 27065 10 8625 10950 19575 7500 27075 11 8635 10950 19585 7500 27085 12 8655 10950 19605 7500 27105 13 8615 11000 19615 7500 27115 14 8625 11000 19625 7500 27125 15 8635 11000 19635 7500 27135 16 8655 11000 19655 7500 27155 17 8615 11050 19665 7500 27165 18 8625 11050 19675 7500 27175 19 8635 11050 19685 7500 27185 20 8655 11050 19705 7500 27205 21 8615 11100 19715 7500 27215 22 8625 11100 19725 7500 27225 23 8655 11100 19755 7500 27255 Code:
CH X1 X2 Sum I.F. Freq 01 8615 10850 19465 7500 26965 02 8625 10850 19475 7500 26975 03 8655 10850 19505 7500 27005 04 8635 10850 19485 7500 26985 05 8615 10900 19515 7500 27015 06 8625 10900 19525 7500 27025 07 8655 10900 19555 7500 27055 08 8635 10900 19535 7500 27035 09 8615 10950 19565 7500 27065 10 8625 10950 19575 7500 27075 11 8655 10950 19605 7500 27105 12 8635 10950 19585 7500 27085 13 8615 11000 19615 7500 27115 14 8625 11000 19625 7500 27125 15 8655 11000 19655 7500 27155 16 8635 11000 19635 7500 27135 17 8615 11050 19665 7500 27165 18 8625 11050 19675 7500 27175 19 8655 11050 19705 7500 27205 20 8635 11050 19685 7500 27185 21 8615 11100 19715 7500 27215 22 8625 11100 19725 7500 27225 23 8635 11100 19735 7500 27235 |
19th Oct 2021, 4:36 am | #13 |
Triode
Join Date: Apr 2021
Location: Lansdale, Pennslyvania, USA
Posts: 46
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Re: Regency Range Gain CB
OK took apart the crystal section ( 4 wires) and resoldered the pins on the 8.655 xtal.. also re soldered the connections when i put back in
turned radio on it worked longer this time before the channels lost sensitivity.. signal went from s9 ( 50uv input) TO S3 .. TX also was about 2 watts less.. so not a complete loss.. Did not swap xtals.. so now looking for a xtal having a hard time finding one Skip Last edited by Vecher1; 19th Oct 2021 at 4:39 am. Reason: added info |
19th Oct 2021, 9:50 am | #14 |
Dekatron
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
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Re: Regency Range Gain CB
You may have to have one made - there are several companies here in the UK who can make one-off crystals to order, I would think there are similar companies in the USA?
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19th Oct 2021, 10:41 am | #15 | |
Dekatron
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
Posts: 11,482
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Re: Regency Range Gain CB
Just had a quick look around at USA crystal suppliers, here is one who says
Quote:
I have not used this company myself and I am sure there are many other similar companies. Just an example of what to look for. |
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19th Oct 2021, 1:42 pm | #16 |
Triode
Join Date: Apr 2021
Location: Lansdale, Pennslyvania, USA
Posts: 46
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Re: Regency Range Gain CB
Thanks, I did email them a week ago.. no response..Will try again
Thanks Skip |
19th Oct 2021, 2:13 pm | #17 |
Dekatron
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
Posts: 11,482
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Re: Regency Range Gain CB
Might be worth a phone call just to find out if they are still trading - I didn't see a 'last updated' date stamp on the website.
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19th Oct 2021, 3:07 pm | #18 |
Dekatron
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
Posts: 11,482
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Re: Regency Range Gain CB
Last update on their Facebook page was 2019.
https://www.facebook.com/bomarcrystal/ Unless they are just really bad at the internet / communications side of things, I fear they may have gone. |
19th Oct 2021, 11:40 pm | #19 |
Nonode
Join Date: Dec 2012
Location: Stockport, Greater Manchester, UK.
Posts: 2,085
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Re: Regency Range Gain CB
Yes, I'd like some more pictures. If you're taking photographs I'd like a back view which shows the maker's nameplate. We know it was made for Regency Electronics, Indianapolis not later than 1964, but that was the time when the American electronics manufacturers were starting to import products from the Far East, starting with Japan and Taiwan
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20th Oct 2021, 12:48 am | #20 |
Triode
Join Date: Apr 2021
Location: Lansdale, Pennslyvania, USA
Posts: 46
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Re: Regency Range Gain CB
Collecting pictures now..
PS I emailed Bomar and got a reply of very expensive.. plus they wanted to know specs.. I have none .. it sounded that they didnt want to be bothered.. So any places over there in UK that does Xtals?? Skip |