in the adjustment menu i can not get the driver idle current down to the 1 amp setting


davebb123456
 

Hi i just wanted to link the out come to the original post,
Hi My mosfet RD60HUF arrived today from china i paid £18 for it i should have found out the price from icom for this mosfet, ,i put it on my peak atlas dca 75 pro and it tested ok, The print on it was a bit light,
and the legs were shorter then the data sheet and the drain leg did not have the slant,as on the data sheet, it may be second hand
I Just zoomed in to the photo that i took before fitting and i think it is used as you can see the indents from were the screws have been,, there was no trace of it being soldered before , the legs are longer then the one that came out,
i took photos just in case it did not work, But it did and it adjusted up to what it should 2.5a above the 00 reading that was 1.533amps, so i am very happy, the radio is not getting as hot, 
i put the old mosfet that i removed on my peak DCA75pro and yes it shows as 2 diodes,
Thanks for all of your help and info,
Thanks Dave 2E0DMB
 


davebb123456
 

Hi 
I have ordered a new UHF fet, it should be with me in about 2weeks time,
I will let you all know when it arrives and I have fitted it,
I hope it will not be a fake,
Thanks all for your help
Thanks Dave 2E0DMB

On Mon, 25 Apr 2022, 17:59 Pasquale S via groups.io, <iw0hex=yahoo.it@groups.io> wrote:

I agree with Steve.

 

When you can not get 2.5 Ampere with UHF Adj, you have UHF mosfet with any issue. You can get power (often 15-25 watt….) but you need to fix with new mosfet RD60HUF.

 

73s Pasquale IW0HEX

 

 

Inviato da Posta per Windows

 

Da: Steve W3AHL
Inviato: lunedì 25 aprile 2022 18:14
A: ic7000@groups.io
Oggetto: Re: [ic7000] in the adjustment menu i can not get the driver idle current down to the 1 amp setting

 

Dave,
The UHF Idle Current definitely needs to be set to 2.5 amps for minimum distortion and spurious emissions.  I would suggest replacing the UHF PA FET.  There are other possible causes, but diagnosing them would be more difficult that replacing the PA.  

Setting the Idle Current establishes the FET's operating set point so that the positive and negative peaks of the RF signal aren't clipped.  There is no or minimal signal applied (thus the term "Idle"), so ALC should not be an issue.  

If you do replace the UHF PA FET, you will should perform all of the TX adjustments for the UHF band, since the newer FETs seem to have different gain than the original ones used, in my experience.  This requires applying the correct audio drive signal at seveal different levels.

Steve, W3AHL

 


Pasquale S
 

I agree with Steve.

 

When you can not get 2.5 Ampere with UHF Adj, you have UHF mosfet with any issue. You can get power (often 15-25 watt….) but you need to fix with new mosfet RD60HUF.

 

73s Pasquale IW0HEX

 

 

Inviato da Posta per Windows

 

Da: Steve W3AHL
Inviato: lunedì 25 aprile 2022 18:14
A: ic7000@groups.io
Oggetto: Re: [ic7000] in the adjustment menu i can not get the driver idle current down to the 1 amp setting

 

Dave,
The UHF Idle Current definitely needs to be set to 2.5 amps for minimum distortion and spurious emissions.  I would suggest replacing the UHF PA FET.  There are other possible causes, but diagnosing them would be more difficult that replacing the PA.  

Setting the Idle Current establishes the FET's operating set point so that the positive and negative peaks of the RF signal aren't clipped.  There is no or minimal signal applied (thus the term "Idle"), so ALC should not be an issue.  

If you do replace the UHF PA FET, you will should perform all of the TX adjustments for the UHF band, since the newer FETs seem to have different gain than the original ones used, in my experience.  This requires applying the correct audio drive signal at seveal different levels.

Steve, W3AHL

 


davebb123456
 

Hi Steve
Thanks for the info,
Like I said I am getting full output power now, but the data sheet does say it is a 60w item, so that is probably why I am still seeing 35w, but I do want it as it should be, so I will change the UHF output, 
And and then do the set up as in the manual,
Thanks for your help,
Thanks Dave, 2E0DMB

On Mon, 25 Apr 2022, 17:15 Steve W3AHL, <w3ahl@...> wrote:
Dave,
The UHF Idle Current definitely needs to be set to 2.5 amps for minimum distortion and spurious emissions.  I would suggest replacing the UHF PA FET.  There are other possible causes, but diagnosing them would be more difficult that replacing the PA.  

Setting the Idle Current establishes the FET's operating set point so that the positive and negative peaks of the RF signal aren't clipped.  There is no or minimal signal applied (thus the term "Idle"), so ALC should not be an issue.  

If you do replace the UHF PA FET, you will should perform all of the TX adjustments for the UHF band, since the newer FETs seem to have different gain than the original ones used, in my experience.  This requires applying the correct audio drive signal at seveal different levels.

Steve, W3AHL


Steve W3AHL
 

Dave,
The UHF Idle Current definitely needs to be set to 2.5 amps for minimum distortion and spurious emissions.  I would suggest replacing the UHF PA FET.  There are other possible causes, but diagnosing them would be more difficult that replacing the PA.  

Setting the Idle Current establishes the FET's operating set point so that the positive and negative peaks of the RF signal aren't clipped.  There is no or minimal signal applied (thus the term "Idle"), so ALC should not be an issue.  

If you do replace the UHF PA FET, you will should perform all of the TX adjustments for the UHF band, since the newer FETs seem to have different gain than the original ones used, in my experience.  This requires applying the correct audio drive signal at seveal different levels.

Steve, W3AHL


davebb123456
 
Edited

Hi Steve
All the bands are now set to output power as specified, But as I could not set the 430mhz final Ideal current to 2.5amp above the 00 setting, as I could only get 400ma over, but I am now getting 35w out at 13.8v ,
As I could only set to 400ma final Ideal current on 430mhz ,do you think it is not in the right class for SSB, it does sound good on another Rx, 
What do you think would do this, would it be the ALC setting,, I might look at this tomorrow, thanks again for your help, 
Thanks Dave 2E0DMB
 

On Sun, 24 Apr 2022, 17:52 Steve W3AHL, <w3ahl@...> wrote:

Dave,

Set the Driver Idle Current adjustment reading to "00", then note the current draw.  Rotate the  dial to INCREASE the current draw by 1.0 amp above the previous reading.  That establishes the proper Driver Idle Current, assuming the adjustment circuits are working correctly.

This only sets the Class A Driver idle current -- it has nothing to do with the output FET's operating points, which are fixed.

The UHF PA FET is often weakened by excessive (>35 VDC) voltage spikes on the 12 VDC power input when operating mobile, due to counter EMF spikes from the engine's starter motor.  In my experience though this usually results in the UHF power output dropping to 5-10 watts or zero.

I would do the complete Transmitter adjustment procedures before attempting any troubleshooting of varying transmitter power output by band.   It may bring all the bands close to specification.  If not, it may lend more insight to where the problem is.  If multiple bands are below the specified output level after correct adjustments, then the Driver (Q504) may be at fault.

It is important to verify that the "12 VDC" input supply is 13.8 volts at full TX PO output and capable of supplying 25+ amps before doing TX adjustments.  More importantly, verify that the supply voltage seen by the circuits inside the unit are > 13.3 VDC under full load by measuring across the TUNER port pins 3-4.  A common problem is excessive voltage drop across the factory supplied fuse holders on the input power cable.  These fuse holders are a poor design and should be replaced with 30 amp automotive style fuse holders.

Steve, W3AHL

 

 


davebb123456
 

Hi Steve
Yes I have just realised what I was doing was incorrect, I have just done it correctly,
I could not get the 430m final ideal current to 2.5a above the 00 , reading, I could only get it 400ma above, all the other bands adjusted at per the manual and I am now getting the 35w at 13.8v on UHF ,it is also more stable
It's good to see that you are still about on all of the forums, I still have my Kenwood ts2000 ,I got this to put in my car,
I will fit a 15v TVS diode as I do have some,
Thanks Dave 2E0DMB


On Sun, 24 Apr 2022, 17:52 Steve W3AHL, <w3ahl@...> wrote:
Dave,

Set the Driver Idle Current adjustment reading to "00", then note the current draw.  Rotate the  dial to INCREASE the current draw by 1.0 amp above the previous reading.  That establishes the proper Driver Idle Current, assuming the adjustment circuits are working correctly.

This only sets the Class A Driver idle current -- it has nothing to do with the output FET's operating points, which are fixed.

The UHF PA FET is often weakened by excessive (>35 VDC) voltage spikes on the 12 VDC power input when operating mobile, due to counter EMF spikes from the engine's starter motor.  In my experience though this usually results in the UHF power output dropping to 5-10 watts or zero.

I would do the complete Transmitter adjustment procedures before attempting any troubleshooting of varying transmitter power output by band.   It may bring all the bands close to specification.  If not, it may lend more insight to where the problem is.  If multiple bands are below the specified output level after correct adjustments, then the Driver (Q504) may be at fault.

It is important to verify that the "12 VDC" input supply is 13.8 volts at full TX PO output and capable of supplying 25+ amps before doing TX adjustments.  More importantly, verify that the supply voltage seen by the circuits inside the unit are > 13.3 VDC under full load by measuring across the TUNER port pins 3-4.  A common problem is excessive voltage drop across the factory supplied fuse holders on the input power cable.  These fuse holders are a poor design and should be replaced with 30 amp automotive style fuse holders.

Steve, W3AHL


Steve W3AHL
 

Dave,

Set the Driver Idle Current adjustment reading to "00", then note the current draw.  Rotate the  dial to INCREASE the current draw by 1.0 amp above the previous reading.  That establishes the proper Driver Idle Current, assuming the adjustment circuits are working correctly.

This only sets the Class A Driver idle current -- it has nothing to do with the output FET's operating points, which are fixed.

The UHF PA FET is often weakened by excessive (>35 VDC) voltage spikes on the 12 VDC power input when operating mobile, due to counter EMF spikes from the engine's starter motor.  In my experience though this usually results in the UHF power output dropping to 5-10 watts or zero.

I would do the complete Transmitter adjustment procedures before attempting any troubleshooting of varying transmitter power output by band.   It may bring all the bands close to specification.  If not, it may lend more insight to where the problem is.  If multiple bands are below the specified output level after correct adjustments, then the Driver (Q504) may be at fault.

It is important to verify that the "12 VDC" input supply is 13.8 volts at full TX PO output and capable of supplying 25+ amps before doing TX adjustments.  More importantly, verify that the supply voltage seen by the circuits inside the unit are > 13.3 VDC under full load by measuring across the TUNER port pins 3-4.  A common problem is excessive voltage drop across the factory supplied fuse holders on the input power cable.  These fuse holders are a poor design and should be replaced with 30 amp automotive style fuse holders.

Steve, W3AHL


davebb123456
 

Hi,
in the adjustment menu i can not get the driver idle current down to the 1 amp setting  the lowest it will go to is 2.56 amps
but it could be some leakage on any of the other output transistors ? 
i get over 100w on all hf, but only 84.7w on 6m, and 44w on vhf and uhf starts at 34w but then drops very fast to 27w, the temp gauge 
rises high very fast when on uhf, I am using a calibrated Bird 4391 to do these tests in to a very good 50ohm dummy load,
but i suppose the best way to test is to test the current were it goes in to each output trany, what do you all think,
Thanks Dave 2E0DMB