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Author Topic: Power increased in the TS-480HX  (Read 58319 times)
NO2A
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Posts: 1214




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« Reply #15 on: October 23, 2013, 07:10:26 PM »


  Wow!!

 Is there anything positive on Eham forums??

 
 Let me say "Thank you" for providing the info to anyone interested in checking out their "service menu".
    There is always the chance that someone will mess with the settings and goof up the radio, that is YOUR chance however.

  You don't need a service menu to be able to goof a rig up!!!

  
  I fully support FREEDOM of information!!
 

  Use it at YOUR own risk, right?






 THANKS for posting the information.





You`re really missing the point here. Doing power mods can damage your rig. To do 250/260 watts output means your input is at least double that. It`s not just finals,but lowpass filters,and other components that cannot handle the kind of heat generated by that kind of mod. They were not designed for it. Those parts will eventually melt.
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W8JX
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« Reply #16 on: October 24, 2013, 04:01:00 AM »

For many years I ran a TS 140 in a mobile at about 150+ watts out. Never had any problems but never put it on a analyzer either but had no complaints. I later demodded rig and solid it and it still works. I case of 480 hx, 50 watts will make no difference down range over 200 watts and 480 is known to get a bit dirty if you exceed its rated output.
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Ham since 1969....  Old School 20wpm REAL Extra Class..
QRP4U2
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Posts: 262




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« Reply #17 on: October 25, 2013, 10:27:24 AM »

The issue with this, any of the other of the power mods is simply this. No thought what so ever is put into the necessary overhead the finals must have to assure linearity, to handle other than flat SWR, and any of a dozen other parameters necessary to assure the radio meets FCC purity specs.

Adjusting bias and/or drive to achieve the power increase, does nothing more than to increase IMD to the point that the resulting distortion can be clearly heard over the air. Doing so, is a selfish act which exemplifies a lack of good engineering knowledge, and in most cases, down right stupidity.

Alan, KØBG
www.k0bg.com

Amen as well!

While these mods may show a small percentage increase in power output, the linearity may suffer considerably.

My view is these finals are already operating on the edge, so why muck with them and possibly shorten their life?

Phil - AC0OB
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AC0OB - A Place Where Thermionic Emitters Rule!
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Besides, when you're a Ham, you experiment with and improve boat anchors - that's what you do!. Smiley
KH6AQ
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Posts: 7718




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« Reply #18 on: October 28, 2013, 06:17:32 AM »

While researching the TS-480HX (I have one) I ran into this interesting old thread. K0BG summed it up when he mentioned "...other than flat SWR..." The originator of the mod did the development work with a 50 ohm load where the mod is safe and should produce a clean signal.

Solid State transceivers are usually designed to deliver rated RF power over a 2:1 impedance range. That is 37.5 to 75 ohms for a VSWR of 1.5:1. To do this the PA output transformer ratio is chosen so that the transistor (collector or drain) swings almost to ground when driving rated RF power into 75 ohms. There is no headroom to drive more than rated power into 75 ohms and this is the first place this power increase modification runs into trouble. When trying to achieve 260 watts into 75 ohms the top 1/3 of the RF conduction cycle is chopped off with one result being increased IMD.

Running 260 watts into 50 ohms will result in a clean signal because the transistor current does not exceed the 37.5 ohm, 200 watt case and there is voltage headroom. Transistor dissipation is less than the manufacturer specified 37.5 ohm, 200 watt case.

Running 260 watts into 37.5 ohms the transistor current is 14% higher than the 37.5 ohm, 200 watt case. Transistor dissipation is approximately 6% higher at 260 watts than at 200 watts. The result may be increased IMD.
« Last Edit: October 28, 2013, 07:06:14 AM by WX7G » Logged
K6PPT
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Posts: 2




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« Reply #19 on: January 31, 2015, 03:25:10 PM »

It's best to leave your TS 480HX "unmolested" state as for the lowpass filtering was probably  not designed much past 200 Watts anyway. The extra 60 Watts on PEP will never be noticed on the receiving end. You also run the risk of spurious emissions that could be outside of the amateur bands, and risk an  FCC notice of violation too. If you feel the need for extra RF power out, I suggest an external RF power amplifier. Your Kenwood will have a much better duty cycle in its original factory state.
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N4ZAW
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« Reply #20 on: February 06, 2015, 09:59:25 PM »

"I did this power mod for incressed SSB peaks. I used an IFR to Check within Kewoods specs. The orginal value was 177 now it is 188. The problem I have is the RF Power meter on the display won't go above 100 Watts after performing this mod. Can anyone help?"

Sure.  Go back and do an entire adjustment of the 480 transmit section starting at the beginning, including the setting of the ALC reference voltage.  The "values" set in the various menu items will be different for any two properly adjusted 480s, so comparing values with other 480s is of no value.  The adjustments should be done in the sequence shown in the service manual.  Jumping into the middle of the sequence and changing something will almost certainly result in screwing up adjustments in later steps. You are talking about an HX model, aren't you?  
I've got a 480 that was over-volted when one of the garbage power supply's pass transistors shorted, sending the output to 22VDC. The owner didn't see this voltage increase, and kept transmitting until he DID notice a substantial drop in RF output. Something went, sure, but I can't tell what yet.
I checked the predriver, drivers and finals, and all appear spec, though, voltage is slightly low at the driver stage and I cannot recall what it was right now -- just that it was slightly lower than the "red" voltage on the schematic.
 As the rig seems to have full AM output, but very low SSB, I'm leaning towards there being a problem with the ALC reference circuit. I did rule-out the mic element by switching mics with a known good one. I have 3.3V measured reference though! ??  Do you have any suggestions before I check the service menu? So far, I've been trying to find the failure, as opposed to 'jacking' values in the menu, or making VR adjustments (bias/drive, et al) ..
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W8JI
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« Reply #21 on: February 07, 2015, 06:10:21 AM »

Most serious CBers run peaked-out radios, and they seem to work fine. There isn't any reason for Hams to not follow their more successful Elmers and peak-out radios.

After all, we can be sure the people designing the radio really designed it to run properly and cleanly at 50% or 100% more power, and simply did not use the extra power. That's usually the way it is done.
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KD0REQ
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« Reply #22 on: February 07, 2015, 08:39:11 AM »

mod up +1 funny.
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KA5IPF
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« Reply #23 on: February 07, 2015, 09:17:52 AM »

"I did this power mod for incressed SSB peaks. I used an IFR to Check within Kewoods specs. The orginal value was 177 now it is 188. The problem I have is the RF Power meter on the display won't go above 100 Watts after performing this mod. Can anyone help?"

Sure.  Go back and do an entire adjustment of the 480 transmit section starting at the beginning, including the setting of the ALC reference voltage.  The "values" set in the various menu items will be different for any two properly adjusted 480s, so comparing values with other 480s is of no value.  The adjustments should be done in the sequence shown in the service manual.  Jumping into the middle of the sequence and changing something will almost certainly result in screwing up adjustments in later steps. You are talking about an HX model, aren't you?  
I've got a 480 that was over-volted when one of the garbage power supply's pass transistors shorted, sending the output to 22VDC. The owner didn't see this voltage increase, and kept transmitting until he DID notice a substantial drop in RF output. Something went, sure, but I can't tell what yet.
I checked the predriver, drivers and finals, and all appear spec, though, voltage is slightly low at the driver stage and I cannot recall what it was right now -- just that it was slightly lower than the "red" voltage on the schematic.
 As the rig seems to have full AM output, but very low SSB, I'm leaning towards there being a problem with the ALC reference circuit. I did rule-out the mic element by switching mics with a known good one. I have 3.3V measured reference though! ??  Do you have any suggestions before I check the service menu? So far, I've been trying to find the failure, as opposed to 'jacking' values in the menu, or making VR adjustments (bias/drive, et al) ..


First and most important rule of troubleshooting

"Alignment does not cure a problem".

A radio that is working and quits doesn't havea n alignment problem. If you go putzing around in the alignment menu it won't fix it and when you finally do figure out what went wrong you will have to go thru the alignment procedure and fix that mess you made.
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W8JX
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Posts: 12204




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« Reply #24 on: February 07, 2015, 10:14:22 AM »


First and most important rule of troubleshooting

"Alignment does not cure a problem".

A radio that is working and quits doesn't havea n alignment problem. If you go putzing around in the alignment menu it won't fix it and when you finally do figure out what went wrong you will have to go thru the alignment procedure and fix that mess you made.


Very true indeed. I remember several years ago a person had run a SUV low on oil and it developed a few bad rod bearing knocks. The poster in denial hoped for a easy fix and clueless parties were telling him that a oil change might fix it. The point of this? People by nature want to believe they did not screw the pooch when they really did and will try any thing sometimes to look for a miracle cure/fix. There is no shortage of those who want to believe too and that offer bad advise rather than admit they are clueless which prolongs the problem being fixed by planting false hopes and not sound advise..
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Ham since 1969....  Old School 20wpm REAL Extra Class..
N4ZAW
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« Reply #25 on: February 07, 2015, 11:12:33 AM »


First and most important rule of troubleshooting

"Alignment does not cure a problem".

A radio that is working and quits doesn't havea n alignment problem. If you go putzing around in the alignment menu it won't fix it and when you finally do figure out what went wrong you will have to go thru the alignment procedure and fix that mess you made.
Please read it again, because you obviously missed my point. I know better than to make my own task more difficult. I'm ASKING for precisely that type of direction, from the poster that begins to address the REAL problem of low RF from this particular radio.
Don't get me wrong -- I'm perfectly willing to go "putzing around" if need be.. After all, that is WHY they stuck a "service menu" in the thing in the first place! But I was asking what the cause for improper ALC reference/response could be, and have no intentions of creating a realignment nightmare for myself, or the next guy (Because if I did, surely, the owner would NOT bring it back for round-two).
This is my first TS-840 "patient". I want to learn something. I'm a ham... That's why I'm here. It's what hams are supposed to do. But I don't plan on killing the patient. If it turns-out to be above my pay grade (which is zip BTW), I have no qualms with giving it back to him so he can ship it out. And we ALL know what THAT pay grade could end up being!
appliance operators learn nothing but the "ten-code". Long live those who contribute here.




.
.
 
« Last Edit: February 07, 2015, 11:23:06 AM by N4ZAW » Logged
KA5IPF
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« Reply #26 on: February 08, 2015, 08:07:26 AM »

My apologies if I took it wrong but the first thing that comes to mind when someone says they are going into the alignment menu AND they are working on a radio with a problem is they are going to try and align away the problem.

You stated the radio(s) have a problem with low SSB audio. How are you measuring this? With a true peak reading meter or a 'scope? The meter in the radio is not peak reading. Why, I don't know??? What happens when you feed a 1 kHz tone at 5 mv level into the mic jack? Can you adjust for full scale ALC reading using the Mic Gain setting? And get full power out? How about a 2 tone signal?

Did the low ssb power out problem exist before the runaway power supply?
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N4ZAW
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« Reply #27 on: February 08, 2015, 02:12:13 PM »

My apologies if I took it wrong but the first thing that comes to mind when someone says they are going into the alignment menu AND they are working oin a radio with a problem is they are going to try and align away the problem.

No need for apologies and given the topic, I agree that twistin VR's and "putzin-around in the service menu" is a recipe for disaster somewhere 'downstream'. So your comments were in-line anyhow,(if I were to ignore the "cause" in "cause -and-effect" ). And thanks for giving me your input.  I had just read Floyd's (K8AC) reply, and his comment about "ALC reference adjustment" sparked thought, as-regards the issue we're having with this particular radio on the banch.
Quote
You stated the radio(s) have a problem with low SSB audio. How are you measuring this? With a true peak reading meter or a 'scope? The meter in the radio is not peak reading. Why, I don't know??? What happens when you feed a 1 kHz tone at 5 mv level into the mic jack? Can you adjust for full scale ALC reading using the Mic Gain setting? And get full power out? How about a 2 tone signal?

I'm referring to this particular rig, with low SSB rf out (or any other that has this issue) that had been over-volted...The main issue is very low RF output in SSB modes. The problem isn't necessarily related to a low audio-input level, but that hasn't been completely ruled-out. Compression-ON does help, but RF is still far too weak. I'm suspecting it is related to the ALC's reference voltage because it doesn't change with audio (3.2V steady as-read from my VTVM at the drivers' control CPU input). I have no means of measuing audio freq input, or testing anything at the MV level. I'm not even sure it really should vary, but I would expect the ALC voltage to vary with audio unless originally set too low, thus, clamping the final output. My thinking is that if I can adjust it in the service menu, and the reference response at the output changes --- Maybe the culprit can be narrowed-down to reference IC, or whatever powers it and it's it's sub-circuit. Or maybe the SWR foldover stage is clamping the ALC too soon?
Either way, there are no test-point voltage verifications that I can see listed in those regions of the schematic I have for it.
(the one in the freebie service manual).
Also, I have never seen any radio with this bizarre type of design before. It's "just not normal" when compared to the norm, the way they have the "dragon's tail in it's mouth",  controlling the final output stages and all that rot -- by software reference -- OYvay! Maybe this is the 'wave of the future', but, if even for just this Kenwood design,  I need to learn about it,  It's about to whup me, anhow (above my pay grade). Wink
 
Quote
Did the low ssb power out problem exist before the runaway power supply?
No, it was fine before the power supply failure incident. BTW, this is the SAT version, not the HX
« Last Edit: February 08, 2015, 02:18:22 PM by N4ZAW » Logged
NZ4ZN
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Posts: 122




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« Reply #28 on: February 08, 2015, 06:25:29 PM »

Oh, don't worry guys....

 According to the negative responses, Hector has told me he would probably never post here again. I was also informed he might want to remove the information from this negative forum.

 Carry on and keep up knocking people down when they present things like this.  No wonder I talk with so many that have a "Dim" view of the Eham forums.

 Also, with the way the USA is going, there will be no such thing as freedom of information before long.
 Yea for Socialism!!  Sad Sad

More drama needed: Score: 2/10

I can appreciate ingenuity. I can also understand how moderately skilled individuals can unknowingly mess things up, the road to hell paved with best intentions and all that aside.

With freedom of information to suggest such modifications also comes freedom of information from people (who know how this stuff actually works) to suggest it is not wise and probably destructive.

Unless this mod was done with the aid of appropriate test equipment under varying conditions (like real life), it is not legitimate. The critics bring up good points about power dissipation, headroom for less-than-ideal conditions and especially the concern for IMD.

No negativity here, and not nearly as much drama as you seem to be used to, just facts.
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KA5IPF
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« Reply #29 on: February 09, 2015, 05:36:15 AM »


No need for apologies and given the topic, I agree that twistin VR's and "putzin-around in the service menu" is a recipe for disaster somewhere 'downstream'. So your comments were in-line anyhow,(if I were to ignore the "cause" in "cause -and-effect" ). And thanks for giving me your input.  I had just read Floyd's (K8AC) reply, and his comment about "ALC reference adjustment" sparked thought, as-regards the issue we're having with this particular radio on the banch.
Quote
I'm referring to this particular rig, with low SSB rf out (or any other that has this issue) that had been over-volted...The main issue is very low RF output in SSB modes. The problem isn't necessarily related to a low audio-input level, but that hasn't been completely ruled-out. Compression-ON does help, but RF is still far too weak. I'm suspecting it is related to the ALC's reference voltage because it doesn't change with audio (3.2V steady as-read from my VTVM at the drivers' control CPU input). I have no means of measuing audio freq input, or testing anything at the MV level. I'm not even sure it really should vary, but I would expect the ALC voltage to vary with audio unless originally set too low, thus, clamping the final output. My thinking is that if I can adjust it in the service menu, and the reference response at the output changes --- Maybe the culprit can be narrowed-down to reference IC, or whatever powers it and it's it's sub-circuit. Or maybe the SWR foldover stage is clamping the ALC too soon?
Either way, there are no test-point voltage verifications that I can see listed in those regions of the schematic I have for it.
(the one in the freebie service manual).
Also, I have never seen any radio with this bizarre type of design before. It's "just not normal" when compared to the norm, the way they have the "dragon's tail in it's mouth",  controlling the final output stages and all that rot -- by software reference -- OYvay! Maybe this is the 'wave of the future', but, if even for just this Kenwood design,  I need to learn about it,  It's about to whup me, anhow (above my pay grade). Wink
 

ALC reduces drive once it reaches a preset level (100w)(dragons tail in mouth). That's the way all ALC circuits work. It is reflected in the ALC voltage going down and the meter reading up. If you don't have adequate drive the ALC doesn't change. In the CW mode do you have an ALC indication on the meter? That would show the ALC circuit is working correctly. The difference to the ALC circuit between SSB and CW is the delay.

If you have ALC indication in CW mode and not in SSB, even with the mic gain up all the way you don't have enough drive. Look at the block diagram and you will find the balanced modulator generates the CW signal and the SSB signal. CW Ok, SSB not, = low audio.

BTW the ALC set voltage is 2.6
« Last Edit: February 09, 2015, 05:43:46 AM by KA5IPF » Logged
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