Recent content by WP4AFB

My question here is, should I expect higher voltage at the drain of fet6? At least higher than the gate? Next time I'll get the source of FET7. On that stage is weird the difference on g1 and g2 voltages, I would expect similar voltages, but it seems to be working fine. I replaced FET6 with...

I added my current voltage readings. RF Voltage as Vpp in red and Vdc in green. Im stuck at this time and really want this radio to come back to life. All help appreciated.

Unit_399 thanks for the snapshot. However those are the DC values which are ok on my radio. I need the AC signal Voltage that I should have there. I have a very low voltage 27MHz signal at the gate and almost nothing in the drain. DC is ok. So it is a mystery for me.

Yes, the frequency at FET6 is correct and can be seen by a reciever next to it. But no measurable rf output from it. I'm not sure what should be the voltage at the gate or drain should be. Having that will be a great help

Im having some issues troubleshooting the whole XMIT circuit of my ROBYN UPD858 board radio. Please refer to the attachment for the discussion and the possible solutions. The transmitter section as I understand it starts with a mixer (FET7) which output is the 27MHz sample to be amplified...

Does anyone have a Service Manual for the Robyn 520D? All I have is similar radios schematics etc. But not one specific for this radio. Attached is the most close I've found. The 18ch version called Ferris 5500

I'm trying to get a Robyn 520D and your comment help me get these. I'll use it to work on mine.