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Author Topic: courier royale cb transformer burnt up?  (Read 474 times)

AC9QC

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courier royale cb transformer burnt up?
« on: January 18, 2022, 10:20:56 PM »

So I have a courier Royale 23 CB. It seems like it would be nice to conver to 10M with a synthesizer at some point. I just wanted to do basic functikn checking first however. I went to power it up and am getting nothing except a pilot light on the front. Not even filaments. The transformer is getting hot but nothing else is. I am seeing no HV on the diodes. I think the primary is burnt up, I may have accidentally done it trying to run the unit on a 12v cable. Any thoughts on how far up a creek I am? If worse comes to worse this seems like a gold mine of parts including a Collins 455khz mechanical filter.
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W9FIB

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Re: courier royale cb transformer burnt up?
« Reply #1 on: January 19, 2022, 05:19:35 AM »

Check continuity from the cord to the transformer.

If OK, remove power and chicken stick the filter caps. Then see if you have continuity through each set of windings. You may need to pull 1 side of the output windings so your meter isn't charging caps or measuring the filament resistance.

Then you will know if it is the transformer or anything in the input power side. Hopefully that will localize the problem.
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73, Stan
Travelling the world one signal at a time.

AC2EU

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Re: courier royale cb transformer burnt up?
« Reply #2 on: January 19, 2022, 07:41:13 AM »

I would think if the pilot light works ( assuming it's a 6 or 12 volt), so should the filaments.
If it's an old AC/DC with plug configuration that switched between modes, perhaps it's mis-wired.
That could account for the lack of filaments and the heating issue.

If the primary was NG, there would be no pilot or HV, I would think...
Besides, the primary should have been protected by a fuse.

W9IQ

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Re: courier royale cb transformer burnt up?
« Reply #3 on: January 19, 2022, 08:44:57 AM »

Make certain that the plug is wired correctly for 120 VAC operation and not for 12 VDC. Here is the power supply area including the correct plug wiring:



A continuity check between pins 4 and 5 will tell you if the 120 VAC primary of the transformer is intact. If the plug isn't jumpered as shown, you won't have the filaments connected for 120 VAC operation.

- Glenn W9IQ
« Last Edit: January 19, 2022, 08:47:35 AM by W9IQ »
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- Glenn W9IQ

God runs electromagnetics on Monday, Wednesday and Friday by the wave theory and the devil runs it on Tuesday, Thursday and Saturday by the Quantum theory.

AC9QC

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Re: courier royale cb transformer burnt up?
« Reply #4 on: January 25, 2022, 10:07:09 AM »

The 120VAC cord was from another Courier CB and wired correctly. I checked the 12VDC cord and it was wired correctly as well.

I measured the primary resistance of both transformers, the suspect one is less than half of the other (10 vs 20 ohms approximately) which seems really fishy. I haven't gotten to disconnecting wiring yet but I think that's the next step. I suspect this is coming out regardless. I will say that if I can get a transformer I'll probably try to get this running again. It's actually a high end unit (I suspect as CBs come anyways) and I think it would be interesting to see what it does on 10 AM. It's got a Nuvistor preamp and Collins Filter unit as well, so I suspect it wasn't a cheapie when it was made.
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