Topics

50 Watt PA Rev. 2


George Korper
 

Got it. Hearing again. Thank you all.


On Mon, Jul 13, 2020, 3:12 PM George Korper via groups.io <georgekorper=gmail.com@groups.io> wrote:
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
-------------------------------
Please reply on list so we can share.
No private email, it goes to a bit bucket due address harvesting


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
-------------------------------
Please reply on list so we can share.
No private email, it goes to a bit bucket due address harvesting


Ronald Taylor
 

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
-------------------------------
Please reply on list so we can share.
No private email, it goes to a bit bucket due address harvesting


George Korper
 

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
-------------------------------
Please reply on list so we can share.
No private email, it goes to a bit bucket due address harvesting


George Korper
 

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
-------------------------------
Please reply on list so we can share.
No private email, it goes to a bit bucket due address harvesting


Ronald Taylor
 

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
-------------------------------
Please reply on list so we can share.
No private email, it goes to a bit bucket due address harvesting


ajparent1/KB1GMX
 

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
-------------------------------
Please reply on list so we can share.
No private email, it goes to a bit bucket due address harvesting


George Korper
 

Ron, assuming I have pin- out correct..

Gate:13.85
Drain .05
Source: 0000

Looking at board bottom with hole in Mosfet on the top, that is reading from right to left


On Mon, Jul 13, 2020 at 11:27 AM George Korper via groups.io <georgekorper=gmail.com@groups.io> wrote:
Thank you. Will check Q3. 
BTW I have never  seen 50 watts on 20. Maybe 30+  watts at 20 volts. 
All the output functions including transformers appear to be okay. 

On Mon, Jul 13, 2020 at 10:49 AM Ronald Taylor <wa7gil@...> wrote:
Hi George. Did you check if Q3 is functioning? On receive the gate of Q3 should be high and the drain should be low. 

Ron

On Mon, Jul 13, 2020 at 7:41 AM Ralf Rosche <ralf.rosche@...> wrote:
Hi George,
output ok means 50W+ ?
If so, the transformers should be correct direction, pease check this twice. 

And there is no short with the ferrit of the torroids in case the enamel of the wire could be damaged?
Check with ohmmeter must be somewhat above some MOhms.

May be one of the pin diode is faulty, or wrong direction?
They are responsible for RX/TX switching.
Hans had a nice description of the functionality in his manual. 

Ralf
 



George Korper
 

Thank you. Will check Q3. 
BTW I have never  seen 50 watts on 20. Maybe 30+  watts at 20 volts. 
All the output functions including transformers appear to be okay. 

On Mon, Jul 13, 2020 at 10:49 AM Ronald Taylor <wa7gil@...> wrote:
Hi George. Did you check if Q3 is functioning? On receive the gate of Q3 should be high and the drain should be low. 

Ron

On Mon, Jul 13, 2020 at 7:41 AM Ralf Rosche <ralf.rosche@...> wrote:
Hi George,
output ok means 50W+ ?
If so, the transformers should be correct direction, pease check this twice. 

And there is no short with the ferrit of the torroids in case the enamel of the wire could be damaged?
Check with ohmmeter must be somewhat above some MOhms.

May be one of the pin diode is faulty, or wrong direction?
They are responsible for RX/TX switching.
Hans had a nice description of the functionality in his manual. 

Ralf
 



Ronald Taylor
 

Hi George. Did you check if Q3 is functioning? On receive the gate of Q3 should be high and the drain should be low. 

Ron

On Mon, Jul 13, 2020 at 7:41 AM Ralf Rosche <ralf.rosche@...> wrote:
Hi George,
output ok means 50W+ ?
If so, the transformers should be correct direction, pease check this twice. 

And there is no short with the ferrit of the torroids in case the enamel of the wire could be damaged?
Check with ohmmeter must be somewhat above some MOhms.

May be one of the pin diode is faulty, or wrong direction?
They are responsible for RX/TX switching.
Hans had a nice description of the functionality in his manual. 

Ralf
 



Ralf Rosche
 

Hi George,
output ok means 50W+ ?
If so, the transformers should be correct direction, pease check this twice. 

And there is no short with the ferrit of the torroids in case the enamel of the wire could be damaged?
Check with ohmmeter must be somewhat above some MOhms.

May be one of the pin diode is faulty, or wrong direction?
They are responsible for RX/TX switching.
Hans had a nice description of the functionality in his manual. 

Ralf
 



George Korper
 

Hi All,
I just assembled a 20 meter Amp and the output is ok.
The unit keys, red light turn on but the receive is very attenuated.
I replaced the two BS 170's, checked all the diodes, checked all the inductors.
I checked all the resistors, because they are from a different supplier. 
I cannot see any components are switched.

During assembly as I was soldering I heard a strange gurgling and pop as I was soldering
Q5 so I replaced it. 


This is my first rev. 2 kit with new parts in it, and my first problem lately with amps.
Has anyone just built a freshly arrived Amp kit?
Where do I look from here?

Again the Amp seems to be working but the receive is attenuated.

Thanks,
George