Have an idea for my Uniden 510.

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fantacmet
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Have an idea for my Uniden 510.

Post by fantacmet » Monday 28th Jul 2008, 18:59

I have a Uniden 510 Pro XL. The normal tweak says to replace the 2.7ohm resistor in front of the final, with a .47ohm. Fine and dandy I can understand that. However........What if I replaced the stock C2166 final with a C1969 final? Would the radio even function? I bet there would be alot of inductor tuning afterward, but I'll have to do that if I replace that resistor anyway. Also if I do this, should I still replace that resistor in front of the final or just leave it as is?

Thoughts? Suggestions? I don't want to burn out my radio. Only working radio I have, and no $$ for a new one. My Cobra 148GTL is major funky, no idea. No power to the thing usually, sometimes I get power, and then everything is all funked on it. I'm working on it though. Replacing components cheapest to most expensive, one by one until the thing works.

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Post by frogman296 » Tuesday 29th Jul 2008, 0:35

im assuming you have the older version...you can replace the final...kind of like putting perfume on a pig though....not worth the cost of the final for small gains.

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Post by fantacmet » Tuesday 29th Jul 2008, 8:25

Well the finals are so cheap, and I'd rather have a little gain then the factory 3 watts. Granted just replacing that resistor and retuning the coils might give me more of a gain then replacing the final. I can get the final around here locally for just a couple of bucks.

The 510's are not bad radio's. The people who keep having them go out must be doing something wrong. I've been running this radio for 5 years, and the friend I got it from had been running for 10 years. No problems.

My particular radio is made in '87, and there is a nice final drive mosfet sitting right at the back bolted to the case for heat dissipation, and it is of the same type of mosfet as a C1969, an npn mosfet power transistor made for rf amplifiers.

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Post by frogman296 » Tuesday 29th Jul 2008, 8:51

mosfets and 1969s are like apples and oranges.....if you have a erf2030 in there now...i would leave it...unless you really want to replace the 2166(3.95@rfparts) with a 1969(9.95@rfparts)

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Post by fantacmet » Tuesday 29th Jul 2008, 9:51

Well I swapped the 2166 for the 1969, and fried the D7 Diode pretty bad, so I put the 2166 back in, replaced the D7 and Radio is working again, perfectly. Biggest issue is, I can't find a source for that damn .47Ohm resistor to replace the 2.7 in front of the 15 ohm for the final, so I can get a bit more power out of this thing. I can't find anything close. Smallest anyone carries 'round here is a 2.2, which isn't enough of a difference to do anything. So I'll just keep looking. Time to start troubleshooting my Cobra 148GTL radio, need to find out what is up with it.

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Post by absorbentgnome » Wednesday 30th Jul 2008, 8:04

I've never understood why you would want to swap around the finals in a radio just to gain an extra watt or so. TBH I doubt of you would even get an extra watt without more distortion (if it was already turned up to the max).

Surely its better to run the radio within spec so you don't overheat the finals as they are only mounted on a thin piece of metal. Also the distortion will be less.

If you need more power why not just drive a cheap burner with your rig. The rig finals have little chance of being destroyed when run conservatively. If something goes really wrong, then at least the cheap burner goes pop and not your rig.

While you could argue that the cost of a final for your rig would be less than a cheap burner - factor in the time you need to replace the final then find that other components are burnt etc.

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Re: Have an idea for my Uniden 510.

Post by Rick » Wednesday 30th Jul 2008, 8:21

People like to play, it keep some of us in work.
Rick.

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Post by vintagetech » Thursday 31st Jul 2008, 21:41

Yes Rick is correct one of the wonderfull things about this hobby is the freedom to do things that might not seem worth it but still instills that I wonder what it will do factor for many of the DIY'ers. And I have been repairing communications equipment (Mostly Citizen Band) for a living since 1964 while working for my uncle in his shop it was great to do what I loved and have it pay for my technical college training and my uncle was really into the "Why buy it if you can build it" aspect of the business.

I will agree that putting a Mosfet in a 510 may not result in a great amount of change but on the other hand if you understand the difference between mosfets and transistors you can really have some fun with them. You may be interested to know that IRF5** series mosfets have been used for many years in almost every other aspect from windshield wiper motor controls to AF amplifiers, switching power supplies and this includes the IRF520 and erf2030 which is nothing more than a relabeled common mosfet that you can purchase in large quantity for 30 cents each. So they tend to be great experimental component.

If you really want to try something wild do the mosfet conversion on any radio you like and then try this. When you have the mosfet working in the final position as it should remove the supply voltage to the Drain pin of the mosfet which is the same as the collector on the old transistor since the modulator for the radio simply modulates the DC supply to the Drain it also modulates the driver so you won't loose the ability to modulate the output. If you don't have a variable power supply pick up one of those el-cheapo's on ebay that have a variable output of up to 30 VDC and about 2-3 amps. substitute the Drain supply voltage with this power source if you have proper heatsink ability and can keep it cool you can up the drain voltage on the IRF520 to 20 VDC with an external supply these mosfet are rated at 100 VDC and are capable of producing upwards of 70 watts @ 10 amps contious current "If everything is in proper design".

NOTE: The beauty of increasing the voltage is that the higher the supply voltage the less current is needed to sustain a higher level of output. This is why in large tube type amplifiers that require 2000 t0 3000 volts for the plates only require a supply capable of delivering that voltage at about 2-3 amps of current capacity and in many cases only 1 amp. and these amps easily delivery around 1000 to 2000 watts and more.


on the drain but you better have sufficient cooling methods in place when you start experimenting at this level. There are other factors that would come into play when doing this it isn't cut and dry as the modulator in most cb's are limited to about 4+ watts of audio but remember we are no longer trying to modulate the final just the driver and some radios like the cobra 29 I did this to was more than able to fully modulate the ouput because essentially you are turning the final section into a linear. "THINK ABOUT IT AN EXTERNAL AMPLIFIER HAS NO AUDIO MODULATOR" operation that is being modulated in the pre stage. I admit there were some things that had to be worked out but at one point I had this 29 deadkey 10 watts with true RMS forward power just touching the 40 watt mark and the feelgood DOSY meter was showing nearly 90 watts peak. And if you are wondering the modulation was very crisp and punchy. A long time friend of mine took this unit with back to florida to continue the experiment I will see if he still has it and have him take some digitals if he can so you see some of the changes. I quess you could say all this was a waste of time because it requires an external supply and extra heatsinking and fan cooling, BUT IT REALLY IS FUN TO TAKE THINGS TO AN EXTREME LEVEL. There are things that must be done when increasing the RF to levels beyond the orignal design of the radio like increasing the capacity of parts in the final tank section to handle the additional RF voltage and current levels that will clearly be present but once you get to looking at the final sections in most cases you rewind tank coils and simply increase the caps and values in no time at all and do on tight budget.

Now there may be some that will read this and say this guy nuts! and mabye so but if you are doubting that the above is valid you better try first then tell me what you think. Ok I'm done and don't be afraid to try anything the only thing that has ever been accomplished by not trying is "NOTHING".

Dennis
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Post by absorbentgnome » Friday 1st Aug 2008, 1:50

Heh good post Dennis.

I am in no way suggesting that experimentation with your radio is wrong. After all getting in there and modifying/uprating/improving sucessfully proves that you've understood the circuit design and used the theory to calculate new values for the appropriate components.

The OP stated

" I don't want to burn out my radio. Only working radio I have, and no $$ for a new one."

so the best thing to do is not mess around substituting finals and modifying the circuit as sometimes things will blow up. I once destroyed a big set of output transistors on a power amplifier project (doh!) because I had decided to uprate by increasing supply voltage and going through the circuit and attempting to calculate new values for certain components. In the end I reverted to the original design as I realised reliability was more important to me than the extra power.

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Post by ramblingman » Wednesday 13th Aug 2008, 13:47

I just recently re-worked one of my pro-510s.
I installed variable power,along with several
other mods..The radio now,will dead key anywhere
from 0 to 5 watt dead key and swing up to 20.
Radio checks are all great.Loud clean audio.
Everyone thinks i am talking on a connex or galaxy.
changed final to 1969 changed driver to a 1957
and several resistors and caps in the rf section.

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Post by absorbentgnome » Wednesday 27th Aug 2008, 20:48

ramblingman wrote:I just recently re-worked one of my pro-510s.
I installed variable power,along with several
other mods..The radio now,will dead key anywhere
from 0 to 5 watt dead key and swing up to 20.
Radio checks are all great.Loud clean audio.
Everyone thinks i am talking on a connex or galaxy.
changed final to 1969 changed driver to a 1957
and several resistors and caps in the rf section.
Ok I'm interested here. Say you've turned up the modulation so that no adjacent channel bleedover occurs but it is loud. Then you have connected a mic with a compressor in it.

What would be the difference between that and the mods you have done?

Why is the peak swing much higher with the 2SC1957 when the supply voltage is the same (apart from the mods of course)? Do these radios drive an output transformer?

Is there an advantage to overmodulating the carrier to the extent that it is distorted? Does this have the effect of compressing the received audio at the expense of some distortion?

[Reason for asking is just to understand it a bit more]
[Ok I anwsered some of those questions by looking at page 4 of http://www.cbtricks.com/members/kd6tas/amsig.htm]

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overpriced am fm cbs etc

Post by hamguy2 » Thursday 30th Oct 2008, 6:14

why would you try to mod a am only cb budget radio for ,also how come some of these radios i have seen in the usa are only am fm ,i dont know how anyone can pay $400 plus us upto $800 for a fm am band only radio thats 1 big joke to me .you can buy a brandknew icom706mk2 g that is all mode all bands for just over what $800us orso my god the am fm ones are more expensive than the ssb ones and there a real good price, thanks david nsw australia :o

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Post by Pioneer621 » Thursday 30th Oct 2008, 20:05

why would you try to mod a am only cb budget radio for ,also how come some of these radios i have seen in the usa are only am fm ,i dont know how anyone can pay $400 plus us upto $800 for a fm am band only radio thats 1 big joke to me .you can buy a brandknew icom706mk2 g that is all mode all bands for just over what $800us orso my god the am fm ones are more expensive than the ssb ones and there a real good price, thanks david nsw australia



Hello everyone!

First I would like to comment on hamguy2's post. I mean no disrespect by any of the following & am simply adding my opinion on the subject.

First, why would anyone want to MOD a cheap budget radio? Why not? It is fun to work on them & they are relatively cheap radios most people can afford to damage if they do not know what they are doing. I enjoy working on radios as well as talking on them; I am usually working on radios while I am talking on my main radio! It is a fun hobby & if you were into the technician aspect then you would understand why we work on the smaller radios & any radio for that matter, it is fun & we like to see what we can get out of them. I big part of this hobby is experimenting with stuff, that’s how you learn.

By the sound of it, you do not work on radios & only talk on them, which is probably why you do not understand the time & trouble someone would put in just to modify a cheap little radio. As far as the AM/FM only radios go, I am not sure which ones you are referring to so I do not have much to say about that, I do agree that US$400 would be way too much for just AM / FM, I would not spend that much without it being a high quality sideband rig that is for sure. I cannot say that I have seen any AM/FM only radios reach US$400 & over, but I do not look at what newer radios are going for very often, maybe it was one of the ones with those built in amplifiers. Take care Hamguy2 & I hope you understood what I was saying.




Back on topic: I recently MODDED a UNIDEN PRO510XL as well as the PRO520XL with a MOSFET final & it worked fine in these little radios. Since these radios do not have much of a heat sink on the back I would not want to push one much past what mine put out without adding a better cooling device, but my output results are as follows. Also, I did not remove the AMC circuit (modulation limiter), However I did add some resitance in series with the limiter diode to allow the radio to reach the 100% mark, however it may be slightly higher then 100% (I can not remember), though you could still hear the limiter catching the high peaks of the modulation so it was not totally defeated.

Tested with a power supply of 14 VDC 20A.
Transmitted into a 50-Ohm Dummy Load

UNIDEN PRO-510XL:
Before Final Conversion but Peaked & Tuned:
4.6 Watt Carrier (Dead Key)
5.9 Watts AVERAGE (RMS) Modulated Swing
20 Watts PEAK (PEP)
100% Modulation

After MOSFET Final Conversion:
6-Watt Carrier (Dead Key)
8 Watts AVERAGE (RMS) Modulated Swing
29 Watts PEAK (PEP)
100% Modulation




UNIDEN PRO520XL:
Before Final Conversion but Peaked & Tuned:
4.8 Watt Carrier (Dead Key)
5.2 Watts AVERAGE (RMS) Modulated Swing
16 Watts PEAK (PEP)
100% Modulation

After MOSFET Final Conversion:
6.2 Watt Carrier (Dead Key)
10 Watts AVERAGE (RMS) Modulated Swing
32 Watts PEAK (PEP)
100% Modulation




Those two radios gained some extra output power, however, is it really enough to make much difference in your signal? Probably not, but it was fun to do & the radios play great! A little closer to a big radio! :D If anyone else out there tries MOSFETS in these radios & attempts higher output power levels then mine, I do recommend the addition of a small piece of aluminum heat sink added to help keep the MOSFET cool as they do run hot & need cooled. Just wanted to post the results from my projects. Talk to you all later & keep having fun working / talking on radios, it truly is a great hobby! Take care everyone! Kyle (Pioneer621)

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its ok i understand they were $99 here

Post by hamguy2 » Thursday 30th Oct 2008, 20:18

hi i know there not even $50 over your way where the 520xl was $149.00 the 540e like the 640e but only am they were $189 ,i was just commenting on doing it it here ,thanks david nsw australia

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Post by johhn » Sunday 2nd Nov 2008, 0:59

Mouser electronics :D , Jamco Electronics :D

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Post by ramblingman » Tuesday 4th Nov 2008, 12:44

Probably because the way it is down here..No one talks ssb local in
our area..If you talk ssb it will have to be dx..And like the man said
thats the fun part of cb radio..Buying a cheap little radio,ive got several
used pro 510s for 5 bucks here..And just seeing how much you can
get out of it before it goes pop and lets the smoke out.You can go as
far as pulling the audio transformer,and putting 24 volts to the final.
All you need is a seperate 24 volt power supply,to hit the final with.
And your 12 volt supply to run the front end.You better have a good
sized heat sink fin and probably even a fan attached to it.Because its
gonna get HOTT.

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Post by mag69 » Wednesday 5th Nov 2008, 1:39

Hey Pioneer621
I just wondering on how to do the mosfet mods on a 510? no one around here knows how to
i tryed to pm you but it woundn't work
Cherokee CBS 2100
Magnum S3
IMax 2000
Uniden 78XL
Cobra 29 LTD ST
Wilson 5000 magnet mounts
Uniden 510XL with a little Wil
Monitoring 27.005 in the Great Lakes State

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Post by Pioneer621 » Friday 7th Nov 2008, 6:30

Hello mag69,
The problem with trying to explain how to install a MOSFET final in this radio is difficult, as many of the parts in this radio are not labeled (mainly capacitors), UNIDEN decided to do that in a few different radios. Makes it extremely difficult to tell someone what parts to change or replace.

I forgot to take detailed pictures of the insides of the PRO510 when I had it or I could have possibly showed you what to do.

It is basically the same conversion as the popular Cobra 29 LTD radios, pretty much just different part location numbers. But your doing pretty much the same thing, maybe slightly different tuning, but overall about the same thing.

Here is what I can recommend doing: look over the MOSFET conversion info for the Cobra 29 LTD, while you are doing that look at the schematic diagram for the Cobra 29 LTD & look how the parts are connected in the circuit (not the whole schematic just the parts the MOSFET instructions tell you to work with & the output amplifier stage). So your basically looking where the parts are connected & how they are connected in the circuit, then looking in your PRO510 & find those same parts (they may have slightly different values but will be close) & change or remove them accordingly, the final, companion part, caps resistors, et. I hope some of that made sense & that is basically what I do when installing MOSFETS in various radios. Then once installed & working, you may need to set the bias voltage on the GATE (PIN-1) of the MOSFET, you will have to locate one of the keying transistors that has about 8 volts DC in TRANSMIT (TX) mode only & install a resistor from that point to the gate of the MOSFET, you want to set it to about 3.5 to 4 volts DC, I usually set it to 4 volts DC.

These are fun little radios to work on! I definitely enjoyed modifying mine & would do it again if I had another one, & I am sure I will when I come across one! Though like I said in my previous post, the extra power gain is not really going to make a difference in your signal, but it is a lot of fun just to see what you can get out of the radio! Even though I know it does not make a whole lot of difference I still do it to most of my radios as I just enjoy working on them & just plain like seeing how much power I can get out of them!

I hope this info helps. Take care! Pioneer621

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Post by mag69 » Friday 7th Nov 2008, 21:42

Thanks Pioneer621 I'll give that a try 8)
Last edited by mag69 on Saturday 8th Nov 2008, 14:02, edited 1 time in total.
Cherokee CBS 2100
Magnum S3
IMax 2000
Uniden 78XL
Cobra 29 LTD ST
Wilson 5000 magnet mounts
Uniden 510XL with a little Wil
Monitoring 27.005 in the Great Lakes State

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Post by Pioneer621 » Saturday 8th Nov 2008, 10:59

mag69,
Your welcome! Have fun! Take care. Pioneer621

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Re: Have an idea for my Uniden 510.

Post by Dodgem250 » Friday 28th Nov 2008, 16:28

You forgot: Doorstop
fantacmet wrote:I have a Uniden 510 Pro XL. The normal tweak says to replace the 2.7ohm resistor in front of the final, with a .47ohm. Fine and dandy I can understand that. However........What if I replaced the stock C2166 final with a C1969 final? Would the radio even function? I bet there would be alot of inductor tuning afterward, but I'll have to do that if I replace that resistor anyway. Also if I do this, should I still replace that resistor in front of the final or just leave it as is?

Thoughts? Suggestions? I don't want to burn out my radio. Only working radio I have, and no $$ for a new one. My Cobra 148GTL is major funky, no idea. No power to the thing usually, sometimes I get power, and then everything is all funked on it. I'm working on it though. Replacing components cheapest to most expensive, one by one until the thing works.

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Re: Have an idea for my Uniden 510.

Post by speedracer6g » Sunday 9th Aug 2009, 5:30

I just did this mod in my shop here today. I realy didnt have much need until they quit making the mini mag. I came up with the same results basically. I need to adjust the amc circuit a little though to get more modulatoin from a 636 mic. I have to play around with the amc and mic amp a little. I dont want to disable it just give the mic a little more gain. this was fun though i thought.

MIkey

Diberts electronics

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