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XPR4550 alignment?

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TAC-10

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Hi guys... I have an XPR 4550 that a friend of mine purchased on Ebay and it appears to have no power out. I offered to take a look at it for him, but unless I'm missing it, I do not see alignment instructions in either the basic or detailed service manuals?

I will also look in the help files in the Tuner application, but I would have expected it to be in one of the service manuals. Anyone run into this?
 
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N4KVE

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Power output can be adjusted in the regular CPS. Mine shows 25 watts on low, & 45 watts on high in the CPS. Checking with a meter, that's correct. GARY
 
com501

com501

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You can set RATED power in the CPS which is not the same as alignment. Make sure that is correct first. For a 45 watt radio on high power, analog, you should see over 10 amps at key down. I have never seen any accurate way of setting alignment short of the autotune option in the service monitor. We use the R8000 and the HP3920 for those functions, both require variable voltage power supplies and current shunts to accurately set the idle current of the PA IC MOSFET arrays in the radios, not something done easily by hand.

If the radio has little or no current on tx, chances are the PA is toast. Rare for a mobile as duty cycles are not that high.
 
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TAC-10

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com501 said:
You can set RATED power in the CPS which is not the same as alignment. Make sure that is correct first. For a 45 watt radio on high power, analog, you should see over 10 amps at key down. I have never seen any accurate way of setting alignment short of the autotune option in the service monitor. We use the R8000 and the HP3920 for those functions, both require variable voltage power supplies and current shunts to accurately set the idle current of the PA IC MOSFET arrays in the radios, not something done easily by hand.

If the radio has little or no current on tx, chances are the PA is toast. Rare for a mobile as duty cycles are not that high.
Click to expand...

Thanks, I was beginning to think his PA is indeed toast, I have not looked at it yet though, or severely off frequency. Sadly I don't have any autotune test gear, just an old HP 8935 so we may be SOL :(
 
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