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#1
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U bet you............I've got it apart right
now......................cleaning the contacts on the regulator board got the low end of the low band VCO working....................the high band VCO only works up at MHz. I am thinking, that with the high S/N, it looks like the owner of this radio sold the R7A face plate to somebody and installed an R7 faceplate on this radio before he moved it out. I played a little bit with the R8...........now I see why everybody likes it so much. I think I will modify it so the preamp works on all ranges, that is, after I remove that pesky MW attenuator. Nice receivers. Pete "dxAce" wrote in message ... Pete KE9OA wrote: Thanks Steve, I am going to take a look at that R8 in a little while and see how it works. My friend is also bring over an R7 S/N 3400 range, with a PLL unlock problem. Just what I always wanted to work on...........another one! Keep those R7's running. |
#2
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![]() Pete KE9OA wrote: U bet you............I've got it apart right now......................cleaning the contacts on the regulator board got the low end of the low band VCO working....................the high band VCO only works up at MHz. I am thinking, that with the high S/N, it looks like the owner of this radio sold the R7A face plate to somebody and installed an R7 faceplate on this radio before he moved it out. I played a little bit with the R8...........now I see why everybody likes it so much. I think I will modify it so the preamp works on all ranges, that is, after I remove that pesky MW attenuator. Nice receivers. I just saw a message on the Drake reflector wondering about a possible change due to the serial number. Thought it must be an R7A vs. an R7. Name Dan, by any chance? |
#3
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How did you guess????????????????????????? He's the guy!
Pete "dxAce" wrote in message ... Pete KE9OA wrote: U bet you............I've got it apart right now......................cleaning the contacts on the regulator board got the low end of the low band VCO working....................the high band VCO only works up at MHz. I am thinking, that with the high S/N, it looks like the owner of this radio sold the R7A face plate to somebody and installed an R7 faceplate on this radio before he moved it out. I played a little bit with the R8...........now I see why everybody likes it so much. I think I will modify it so the preamp works on all ranges, that is, after I remove that pesky MW attenuator. Nice receivers. I just saw a message on the Drake reflector wondering about a possible change due to the serial number. Thought it must be an R7A vs. an R7. Name Dan, by any chance? |
#4
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![]() Pete KE9OA wrote: How did you guess????????????????????????? They don't call me 'Ace' for nothing! He's the guy! Pete "dxAce" wrote in message ... Pete KE9OA wrote: U bet you............I've got it apart right now......................cleaning the contacts on the regulator board got the low end of the low band VCO working....................the high band VCO only works up at MHz. I am thinking, that with the high S/N, it looks like the owner of this radio sold the R7A face plate to somebody and installed an R7 faceplate on this radio before he moved it out. I played a little bit with the R8...........now I see why everybody likes it so much. I think I will modify it so the preamp works on all ranges, that is, after I remove that pesky MW attenuator. Nice receivers. I just saw a message on the Drake reflector wondering about a possible change due to the serial number. Thought it must be an R7A vs. an R7. Name Dan, by any chance? |
#5
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I found the location of the MW attenuator.......................it appears
that I will have to change the 150pF shunt cap at the filter input to 220pF, to make the filter symmetrical. This is for the R8. As far as the R7, the 25V power supply line for the tune voltage was only 7V. This is the reason the receiver only locks on the low ranges. Unless the power supply board has gone through some sort of revision, somebody replaced the 78L24 regulator with an LM317Z. The 78L24 is a low current 24V positive regulator, while the 317 is an adjustable regulator. Totally different pin-out from the original, and it would never work in this circuit. Basically, there is a multivibrator circuit that provides 35VAC. This voltage is full-wave rectified with a bridge consisting of r 1N4148s, filtered, and applied to the 24V regulator. I should be able to get it running, once I get the correct part. Pete "dxAce" wrote in message ... Pete KE9OA wrote: How did you guess????????????????????????? They don't call me 'Ace' for nothing! He's the guy! Pete "dxAce" wrote in message ... Pete KE9OA wrote: U bet you............I've got it apart right now......................cleaning the contacts on the regulator board got the low end of the low band VCO working....................the high band VCO only works up at MHz. I am thinking, that with the high S/N, it looks like the owner of this radio sold the R7A face plate to somebody and installed an R7 faceplate on this radio before he moved it out. I played a little bit with the R8...........now I see why everybody likes it so much. I think I will modify it so the preamp works on all ranges, that is, after I remove that pesky MW attenuator. Nice receivers. I just saw a message on the Drake reflector wondering about a possible change due to the serial number. Thought it must be an R7A vs. an R7. Name Dan, by any chance? |
#6
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In article , Pete KE9OA
wrote: U bet you............I've got it apart right now......................cleaning the contacts on the regulator board got the low end of the low band VCO working....................the high band VCO only works up at MHz. I am thinking, that with the high S/N, it looks like the owner of this radio sold the R7A face plate to somebody and installed an R7 faceplate on this radio before he moved it out. I played a little bit with the R8...........now I see why everybody likes it so much. I think I will modify it so the preamp works on all ranges, If you do this mod, would you post a how-to? I have an R8; I would like to make the pre-amp work on LW NDBs. thanks, -j that is, after I remove that pesky MW attenuator. Nice receivers. Pete "dxAce" wrote in message ... Pete KE9OA wrote: Thanks Steve, I am going to take a look at that R8 in a little while and see how it works. My friend is also bring over an R7 S/N 3400 range, with a PLL unlock problem. Just what I always wanted to work on...........another one! Keep those R7's running. |
#7
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I sure will. Probably won't get to it for a few days. Right now, I am
fighting the flu AND fixing that R7 Pete "JoanD'arcRoast" wrote in message . .. In article , Pete KE9OA wrote: U bet you............I've got it apart right now......................cleaning the contacts on the regulator board got the low end of the low band VCO working....................the high band VCO only works up at MHz. I am thinking, that with the high S/N, it looks like the owner of this radio sold the R7A face plate to somebody and installed an R7 faceplate on this radio before he moved it out. I played a little bit with the R8...........now I see why everybody likes it so much. I think I will modify it so the preamp works on all ranges, If you do this mod, would you post a how-to? I have an R8; I would like to make the pre-amp work on LW NDBs. thanks, -j that is, after I remove that pesky MW attenuator. Nice receivers. Pete "dxAce" wrote in message ... Pete KE9OA wrote: Thanks Steve, I am going to take a look at that R8 in a little while and see how it works. My friend is also bring over an R7 S/N 3400 range, with a PLL unlock problem. Just what I always wanted to work on...........another one! Keep those R7's running. |
#8
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I checked the sensitivity of the R8 at the MW band edges vs the adjacent
ranges. No difference in sensitivity over the whole tuning range. 10uV RF input gives S6 meter reading, indicating that there is no MW attenuator in the non-European version. Good news.............not I don't have to tear into it until I figure out the preamp enable mod for the LW/MW ranges. Pete "Pete KE9OA" wrote in message . .. I sure will. Probably won't get to it for a few days. Right now, I am fighting the flu AND fixing that R7 Pete "JoanD'arcRoast" wrote in message . .. In article , Pete KE9OA wrote: U bet you............I've got it apart right now......................cleaning the contacts on the regulator board got the low end of the low band VCO working....................the high band VCO only works up at MHz. I am thinking, that with the high S/N, it looks like the owner of this radio sold the R7A face plate to somebody and installed an R7 faceplate on this radio before he moved it out. I played a little bit with the R8...........now I see why everybody likes it so much. I think I will modify it so the preamp works on all ranges, If you do this mod, would you post a how-to? I have an R8; I would like to make the pre-amp work on LW NDBs. thanks, -j that is, after I remove that pesky MW attenuator. Nice receivers. Pete "dxAce" wrote in message ... Pete KE9OA wrote: Thanks Steve, I am going to take a look at that R8 in a little while and see how it works. My friend is also bring over an R7 S/N 3400 range, with a PLL unlock problem. Just what I always wanted to work on...........another one! Keep those R7's running. |
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