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 Post subject: Knight Star Roamer Electrolytic
PostPosted: Jun Wed 12, 2019 6:32 pm 
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Joined: Jan Mon 11, 2016 1:19 pm
Posts: 543
Location: Spring Lake Mi
http://www.mcmlv.org/Archive/Radio/Knig ... Roamer.pdf

The Electrolytics were replace with outlandish values, I do not know what the voltage values should be. I only have some 250V and 450V. I'm wondering if 250V would work for all four of them without any issues.

Thanks.

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Jim KA8ZXJ
Spring Lake MI 49456


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 Post subject: Re: Knight Star Roamer Electrolytic
PostPosted: Jun Wed 12, 2019 7:03 pm 
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Joined: Jun Wed 08, 2011 2:33 am
Posts: 9410
Location: Ohio 45177
Based on the voltages shown on the schematic, I would say your 250V caps ought to be fine. I would think the closest value that is available commonly is 33 uF. The 50 uF across the cathode resistor of the audio output probably only needs to be something like 25 volts. And make sure someone has not changed the fuse to something higher than the 1 amp stated.

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 Post subject: Re: Knight Star Roamer Electrolytic
PostPosted: Jun Thu 13, 2019 12:08 pm 
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Joined: Jan Mon 11, 2016 1:19 pm
Posts: 543
Location: Spring Lake Mi
wazz wrote:
Based on the voltages shown on the schematic, I would say your 250V caps ought to be fine. I would think the closest value that is available commonly is 33 uF. The 50 uF across the cathode resistor of the audio output probably only needs to be something like 25 volts. And make sure someone has not changed the fuse to something higher than the 1 amp stated.

Thank you.

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Jim KA8ZXJ
Spring Lake MI 49456


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 Post subject: Re: Knight Star Roamer Electrolytic
PostPosted: Jun Sat 15, 2019 1:20 pm 
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Joined: Nov Sun 15, 2015 8:32 pm
Posts: 137
Location: Poteau, OK
Jimradio wrote:
http://www.mcmlv.org/Archive/Radio/KnightkitStarRoamer.pdf

The Electrolytics were replace with outlandish values, I do not know what the voltage values should be. I only have some 250V and 450V. I'm wondering if 250V would work for all four of them without any issues.

Thanks.


I have the Star Roamer assembly manual with schematic on my website. Click the
link below to download the manual free.

https://w5rkl.com/wp-content/uploads/2015/02/Star-Roamer.pdf

Go to the schematic and note the maximum DC voltage on the plates of the various tubes.
You can determine quite close to the proper DC voltage rating of the filter capacitors by
studying the voltages listed on the Star Roamer schematic then double the voltage to
get a safe rated filter capacitor.

Having said that you can get a "new" multi capacitor designed for the Star Roamer from Tom
at hayseedhamfest.com for only $18. Click the link below to see the cap.

https://hayseedhamfest.com/collections/misc-ham

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Mike W5RKL
https://www.w5rkl.com


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 Post subject: Re: Knight Star Roamer Electrolytic
PostPosted: Jun Sat 15, 2019 9:57 pm 
Member

Joined: Jan Mon 11, 2016 1:19 pm
Posts: 543
Location: Spring Lake Mi
w5rkl wrote:
Jimradio wrote:
http://www.mcmlv.org/Archive/Radio/KnightkitStarRoamer.pdf

The Electrolytics were replace with outlandish values, I do not know what the voltage values should be. I only have some 250V and 450V. I'm wondering if 250V would work for all four of them without any issues.

Thanks.


I have the Star Roamer assembly manual with schematic on my website. Click the
link below to download the manual free.

https://w5rkl.com/wp-content/uploads/2015/02/Star-Roamer.pdf

Go to the schematic and note the maximum DC voltage on the plates of the various tubes.
You can determine quite close to the proper DC voltage rating of the filter capacitors by
studying the voltages listed on the Star Roamer schematic then double the voltage to
get a safe rated filter capacitor.

Having said that you can get a "new" multi capacitor designed for the Star Roamer from Tom
at hayseedhamfest.com for only $18. Click the link below to see the cap.

https://hayseedhamfest.com/collections/misc-ham

Thank you did not know about hayseed...............

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Jim KA8ZXJ
Spring Lake MI 49456


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 Post subject: Re: Knight Star Roamer Electrolytic
PostPosted: Jun Fri 21, 2019 12:26 pm 
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Joined: Jan Mon 11, 2016 1:19 pm
Posts: 543
Location: Spring Lake Mi
Thanks guys for your help, it is now restored and working.

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Jim KA8ZXJ
Spring Lake MI 49456


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 Post subject: Re: Knight Star Roamer Electrolytic
PostPosted: Jun Fri 21, 2019 5:22 pm 
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Joined: Jun Wed 08, 2011 2:33 am
Posts: 9410
Location: Ohio 45177
Well it is a solid state rectifier. There may be higher voltage at the diode cathode before the tubes warm up and conduct as well as a surge at turn on that is more dramatic than with a tube rectifier that does not conduct immediately. Otherwise you could put a meter on that diode and see what the initial voltage is, if you want to. I don't imagine it exceeding the 250V rating of the caps but that is theoretical.

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Reddy Kilowatt says; You smell smoke? Sorry about that!


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 Post subject: Re: Knight Star Roamer Electrolytic
PostPosted: Jun Sat 22, 2019 1:12 am 
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Joined: Dec Sun 14, 2008 3:33 pm
Posts: 868
Location: Tokyo
Just to point out there are at least two versions of the Star Roamer, and the plate voltages are different. One version includes a switch on the regeneration control that adds a bypass cap to the IF amp cathode resistor to increase gain.

Rob


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