Mike,
On CW, frequency 3.95Mhz I get about 35v pk-to-pk on the tab of the
irf510's. That's a little higher than you show.
Ck message 43844. It has a jpg from ve3pe showing some of the voltages
(dc and rf) for the driver stage. This might be of some help to you.
tim ab0wr
On Thu, 22 Mar 2018 16:05:25 -0700
"Mike R." <ubitx@...> wrote:
I'm running out of ideas and need some help. First, it would be great
if there was a schematic with voltage measurements on it that one
could use for debugging a non-working ubitx. I have the following set
up: ubitx to WM-1 wattmeter to dummy load. I'm using CEC's software
v1.04. I can receive just fine. I've adjusted the bias of the 510's
to 100ma each. I've done calibration and BFO setting. Once again the
radio works fine on receive. I have very low output on all bands. I
have made the following measurements and I'm looking for someone to
help me figure out where the power is going. I'm running at 13.8V
(was at 12V, but thought extra would help the PA). The 12V numbers
are equally bad, just a bit lower. So, I measured from the wiper of
RV1, the power out, and the antenna voltage (on a 50mhz scope) the
following: RV1 at full clockwise: Band ?? RV1 ? ? Power ?? Ant V
80 ? ?? 640mv ?? 4.8W ?? 21V
40 ? ? ?? 520mv ? ? 700mw? 12.2V
30 660mv ? ? 700mw ? 15v 20
1.2V ? ? ? ? 300mw ? 14v 15
640mv ? ?? 7mw ? ? ? 2.8V 10 ? ? ? ? 340mv ? ?? 3mw ? ?? 600mv Moving
RV1 counterclockwise will lower these values as would be expected. Do
these values for RV1 look right? If they do then the problem is
further down the PA chain. Again, I wish there was a table of
receive/transmit voltages that one could reference.
So, then I thought I'd measure the clocks to see if there was
anything amiss there: at 7.150 Clk0 12Mhz 1.44V on receive; 0V on XMT
Clk1? 660mw at 33Mhz; 0V receive
CLK2 1.2V XMT (7.150mhz); 520mv receive 43Mhz
Help would be very much appreciated. Thanks.
73, Mike W1USN
