An update on my XV50.
Having failed to get the pa bias greater than around 500mA I decided to
press ahead with the rest of the alignment. It is now basically working
but only at the 5-10W level. If I increase the drive to 20W it
effectively limits at that level, no more than 20W can be
I am aligning my new XV50, latest build using the RA30H0608M module and
having issues with setting the quiescent bias of the pa as per the
manual. I see others have had this same problem but I can find no
answers.
The manaul calls for R39 to be adjusted for 20mV on the DMM across
TP3/4
Dave,
The PA bias control usually has much greater range than is needed, and
the PA bias input should draw very little current.
Check the resistance of R39. Is there a chance that you swapped R39 and
R10 during the assembly?
73,
Don W3FPR
On 10/24/2014 6:46 AM, Dave Sergeant wrote:
I am
R39 is correct (10k pot) as is R10 (100k) and all the measurements
confirm this. The adjustment range, measured at pin 2 of the amplifier
module, is 2.5-4.7V, also what is expected from the circuit. The
maximum voltage is limited to 4.7V because of the 5mA flowing through
R28 which swamps the
Dave,
R39 for the XV50 should be a 1k pot. Typo or incorrect component?
The bias voltage is not the important factor, important is the ability
to produce the proper idling current - that is why the instructions tell
you to measure the voltage between TP3 and TP4 when setting the bias.
The
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