| Author |
Message |
    
Harpoonman
| | Posted on Friday, September 21, 2001 - 9:17 am: | 
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Hey 307!
I've been enjoying my new VR9000 for the past couple of days. It was modified by Copper and I am quite satisfied with its output power and other basic functions. But, I have a couple of questions about some minor (I think) problems I've encountered.
By the way, I am currently running the VR9000 inside from a 10 amp regulated power supply until I get it into the car this weekend, and I have done a search here in the forum on the VR9000 and pulled down everything I can find on this radio here.
Question 1:
I've been getting pretty good radio reports from folks in my area with this radio, but there are still a significant number who report that my audio is not too high and sounds somewhat muffled and maybe a bit "fuzzy". Upon listening to myself through the talkback feature AND through a good monitor, on both AM and SSB, I tend to agree. The audio could stand to be a little cleaner sounding. The audio does seem to sound a little better on AM than on SSB, too. Now, keep in mind that I am just using the stock microphone. Tonight, I'll be wiring one of my amplified D-104s for the VR9000 and see how it sounds with this mic. I've read in several places here in the forum that clipping a particular resistor will "open up" the modulation for this radio by disabling the AMC. The resistor is R249. Do you recommend my doing this to improve the audio output power and sound quality? If so, exactly where is R249 located in the radio? Also, was this procedure done when Copper performed the $30 modifications?
Question 2:
As noted in several places here in the forum, the VR9000 does indeed have a mild hum in the audio when transmitting. I can hear it on both AM and SSB and with both the talkback feature on and through my monitor. Now, when I turn off the frequency counter display this hum completely disappears! When I turn it back on, it is back. The hum does not seem to be extreme at this time, and it may not even be noticable to most listeners a few miles out, but I don't want it to get any worse! I read in the forum that the "addition of a 330 microfarad capacitor on the B+ to the counter to ground" would likely be the fix for this (quoted from 307). 307, could you verify this and has anything more come out on this issue? Also, what do you mean by the "B+ to the counter".
Bottom line here is, should I tackle these little problems myself (I'm not GREATLY proficient technically, but still I'm good with a soldering iron and I'm learning), OR should I just arrange to return the radio to Copper and let you fix them?
Thanks for any and all help you could give!
Harpoonman |
Knight Ranger
| | Posted on Friday, September 21, 2001 - 5:41 pm: |
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I would suggest NEVER cutting out the limiter...These radio makers don't put any more parts then they have to in these radios so they can keep the price down...Besides on that radio there is no mic gain controll. Leave the limiter in place it is there for a reason...get a good mic mb575 or d104 handheld and wire it up...alot of the time they have a far superior mic element in them compaired to the stock mic which will improve the audio quality and give you a way to controll the "audio" external. As far as the hum yes that is the correct procedure to eliminate the problem....if you really want to get broadcast type audio try speech processing..I am sure someone can point you in the right direction...
hope this helps a little
73's Knight Ranger
Radio Control inc. |
Metro
| | Posted on Friday, September 21, 2001 - 9:29 pm: |
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I have the VR and have had no problems with the exception of a loose calibration knob on the first unit they sent me. I'd send it back if I were you, if you dig into it and screw something up, they may hold you responsible and charge you to fix it.
Metro 446 |
Harpoonman
| | Posted on Saturday, September 22, 2001 - 10:22 am: |
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Hey Knight Ranger and Metro,
Thanks for the advice. Yeah, I'll leave that resistor alone. In fact, I wired one of my amplified D-104s for the radio last night, and BOY what a world of difference it made! Of course, I'm still running it inside on a 10 amp power supply and I hope to get it into the car sometime this weekend. Everyone said that the radio was really LOUD with the D-104 installed on it. I could only turn up the audio gain pot on the bottom of the D-104 just a tad or my audio would otherwise turn into a sort of whine. Properly set, though, it worked beautifully.
However, another problem has cropped up which may require my sending the radio back to Copper. I noticed this on Wednesday night when I was first testing the radio and it occurred again last night. At intermittant times, the VR900's modulation would begin to oscillate on SSB. This happended on Wednesay using the stock mic and again last night using the D-104, so I don't think it is the mic. I checked all connections, including those from the power supply, and I don't think this oscillation is caused by RF since I'm not close to the antenna. The oscillation appears to occur after I have been talking back and forth for a while and after I have been keyed up for a fair period (like a couple of minutes straight). I think this is heat-related, and that some component is getting too hot. I checked the temperature of the radio and while it does get warm after extended transmissions, it is not extremely hot at all. I can put my hand on the heat sink in the back and it never gets so hot that I can't keep my hand on it. Still, the oscillation in my modulation appears to be either time-related and probably heat-related.
Any ideas 307 or others about what this could be caused by and what I should do about it? Return the radio? Fix it myself under your guidance?
I greatly appreciate the help!
Harpoonman |
Harpoonman
| | Posted on Thursday, September 27, 2001 - 8:39 am: |
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As an update on the problems I expressed above, I htink I've solved them with the help of 307 and the Forum Master. 307 felt that based on the symptoms I described the final bias voltage was too high causing a carrier on SSB. He suggested that I find the pot near the final transistor labeled "bias" and adjust it one-quarter turn counter clockwise to reduce the voltage.
Well, the only glitch here is that as there are TWO final transistors there are TWO bias pots, one for each transistor. Secondly, these pots are not labeled "bias" at all. They are labeled as "VR20" (on the left) and "VR10" (on the right), but I really had to look carefully for the VR labeling on the PC board as the lettering is obscured by other components. Each VR was set at the same position (about 11 o'clock). So, I adjusted each VR about 1/8th turn counter clockwise. They would not go back one-quarter turn. I did this and then keyed up observing the watt meter and listening to my modulation through my monitor. Everything remained the same in terms of power and sound quality, except that I haven't had that oscillation or carrier since I did this. I experimented a little by increasing VR 20 and VR 10 by about a quater turn clockwise briefly. The only audible change was in modulation...it increased slightly. I set them back to where I had first adjusted them.
I made no other changes to the radio, but I did look for R249 that others here have said controls the AMC. I found it and it has already been clipped! Was sticking straight up..
The VR9000 is in the car now and upon limited first testing I am VERY pleased to report that my Ford does not cause NEAR the interference that I was afraid it might. Even the blower fan and wipers don't increase the noise level too much. GREAT!
I'm taking a trip this morning, so I get to really see if the adjustment is indeed a fix and see just how well the radio works (the current antenna is a limiting factor right now).
Harpoonman |
BEATLE
| | Posted on Saturday, November 24, 2001 - 8:39 am: |
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Trying to find all the mods I can get on the Magumn ALPHA FORCE. THANK YOU BEATLE |
307
| | Posted on Tuesday, November 27, 2001 - 8:40 pm: |
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I wanted to give you some time , I knew you could fix it...As for the buzz , that posting I put on the Forum will fix that...
307 |
Sonoma
| | Posted on Thursday, December 06, 2001 - 9:49 pm: |
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I JUST GOT My VR 9000 CB THE ONLY THING I HAVE IS THAT WHEN YOU TURN THE RADIO ON THE FREQ COUNTER READS 2 HZ ABOVE WHAT IT SHOULD BE SUCH AS SET IT TO 27565 AND THE COUNTER SHOWS 27567 AND I CAN NOT TALK ON SIDE BAND WITHOUT TURNING THE COURSE CLARIFIER AND AS THE RADIO WARMS UP THE HZ STARTS MOVING TOWARDS 27565 AND I HAVE TO KEEP ADJUSTING THE CORSE CLARIRIER TO KEEP IT READING 27565 FOR ABOUT 30 MIN THEN IT STABLIZES AND JUST USE THE FINE CLAIFIER TO TUNE IN EACH PERSON IF OFF SOME.307 OR 181 I NEED YOUR HELP ANY IDEAS.SONOMA
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307
| | Posted on Friday, December 07, 2001 - 8:51 am: |
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Sonoma..First turn off your CAPITAL LOCK button on your keyboard.Then remove the bottom cover on the VR-9000 and slightly , when I say slightly I mean if you move it more than 1/10 turn , you went to far..Set you clarifier to exactly 12:00 before any adjustments are made and make sure you wait at least 15 minutes for thee radio to warm up and stabilize...Move :
L19 for AM
L20 for USB
L21 for LSB |
Spydrman
| | Posted on Friday, December 07, 2001 - 9:57 am: |
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Mine does the same thing and I personally don't think that it makes a big difference that I can notice anyway. I'm on channel 4 a lot,AM side, and the people I'm talking to are usually within a couple of miles of me. Mine warms up also within reasonable time. I was never really concerned about it, I just adjusted the freq. accordingly.... |
Sonoma
| | Posted on Friday, December 07, 2001 - 10:00 am: |
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307 WHICH WAY DO I TURN THE PODS YOU DID NOT SAY AND TO MAKE SURE YOU GOT MY MESSAGE RIGHT IT IS THAT AFTER THE RADIO IS WARMED UP THE CLARIFIER IS LINED UP WHERE IT SHOULD BE .I CAN NOT USE THE RADIO ON MY 20 MIN DRIVE TO WORK IT IS NOT ON FREQ,THANKS SONOMA.PS I LIKE MY CAPS LOCK.HA! HA! |
Sonoma
| | Posted on Friday, December 07, 2001 - 3:53 pm: |
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Hi 307 on my 9000 I tried what you said and after awhile I was off freq again so I set it back up on center warm and the radio worked fine I let it cool down and it was off freq again so I put heat on the crystal by the am pod with a solder gun and then when i turned it on it was on freq.could it be the crystal is sinsative to temp and is not staying within tolerance of the freq?also i had the hum in the freq counter and could not find a 330 uf capacitor so I installed a 220 uf cap and it took 99.9 % of the hum out.just for everyones info.let me know what you think about the crystal and maybe there is another one that is not so sinsative to cold.If you think that is it. |
307
| | Posted on Friday, December 07, 2001 - 9:04 pm: |
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The 10.240 Reference crystal could be at fault and most likely is. Email me your address at tech307@copperelectronics.com and I will send you a temp compensated crystal that will work.
307 |
Spydrman
| | Posted on Saturday, December 08, 2001 - 7:55 am: |
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I must know, when "clipping" R249, are you saying taking a pair of dykes to one side of the leg? Does it matter what side of the resister to cut?
Thanks,
Spydrman |
307
| | Posted on Saturday, December 08, 2001 - 7:16 pm: |
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Clip one side , thats it...
307 |
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