Re: 50 Watt PA Rev. 2


George Korper
 

Ron,

Looks like a bad trace between D3 and D5. I can see it under magnification.
Again you astonish me!

Alll Best 73,
George

On Mon, Jul 13, 2020 at 3:10 PM Ronald Taylor <wa7gil@...> wrote:
George, check continuity from the input connector to one side of C1 and from the other side of C1 to the anode of D3, then pull out the jumper wire and fix whichever trace isn’t electrically there. Sounds like you’ve found it. 

Ron

On Mon, Jul 13, 2020 at 11:51 George Korper <georgekorper@...> wrote:
When I squeeze the board in the vicinity of C1, it picks up....
I changed both capacitors and resoldered the BNC to no avail.
Someday I will hardwire...hee hee. 

On Mon, Jul 13, 2020 at 2:09 PM George Korper <georgekorper@...> wrote:
Ron, 


D5 is very low. 07 volts  D3 is .7volts. I Changed D5. No change. 
Maybe C16 is bad...I'll try changing it.. I never did like the way it is too large  Hi Hi. 

On Mon, Jul 13, 2020 at 12:55 PM Ronald Taylor <wa7gil@...> wrote:
George, that sounds right. Now, while in receive mode check the voltage drop across D3 and then across D5. Both should show 0.6 volts or so of drop. If that's good then the problem is elsewhere. All that's left of this part of the circuit are C1 and C16. You might want to check and make sure they are indeed 1 uF ... (105) just to be sure... Good luck...Ron

On Mon, Jul 13, 2020 at 9:23 AM ajparent1/KB1GMX <kb1gmx@...> wrote:
RX attenuated...  

Q3 and Q5 are RX switching, they only have DC and during RX.

The drain of Q3 should have near 0 volts (less than 1) during RX.
gate of Q3 should have More than 6V.

IF gate of Q6 is not at least 6V during RX check Q5 gate of
Q5 should be 0 Volts or very close to that.
If that is not true check what is wired to jack X2 (Keying) or
possible Q6 in wrong or has a shorted solder connection.

Allison
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