K3 PIN Diodes blown ?


Vic Lindgren G4BYG <g4byg@...>
 

Can anyone help  with my K3 fault
Which PIN diodes are most likely to need replaceing with a no rx fault condition??
Transmitter is good.Just the rx that is dead.
No error messages.
Both Main and Sub rcvrs not working.
Checked seating of plug in boards and patch leads all appear to be seated correctly.
Configuration has not been altered. One day ok next day faulty.
Suspect rf has got into the RX path.
Any help would be greatly appreciated.
73
Vic G4BYG


Ken K6MR
 

Once when my SO2R filters quit working I fried D25 and D26 in the TR switch.  Page 2 of 4 of the schematic.  The path is very easy to trace if you have a sig gen and scope.  When they go dead, they are dead. 

 

If you have a parts supplier over there you can get the exact part number from Elecraft support.  They are pretty common devices.

 

Ken K6MR

 

From: Vic Lindgren G4BYG
Sent: Wednesday, April 21, 2021 04:39
To: Elecraft-K3@groups.io
Subject: [Elecraft-K3] K3 PIN Diodes blown ?

 

Can anyone help  with my K3 fault
Which PIN diodes are most likely to need replaceing with a no rx fault condition??
Transmitter is good.Just the rx that is dead.
No error messages.
Both Main and Sub rcvrs not working.
Checked seating of plug in boards and patch leads all appear to be seated correctly.
Configuration has not been altered. One day ok next day faulty.
Suspect rf has got into the RX path.
Any help would be greatly appreciated.
73
Vic G4BYG

 


Henk PA0C
 

Check the switching voltage on those diodes as well. 
My dead receiver was caused by an open rf-choke while the diodes were still ok.
73 Henk
PA0C


-------- Oorspronkelijk bericht --------
Van: Ken K6MR <k6mr@...>
Datum: 21-04-2021 18:30 (GMT+01:00)
Aan: Elecraft-K3@groups.io
Onderwerp: Re: [Elecraft-K3] K3 PIN Diodes blown ?

Once when my SO2R filters quit working I fried D25 and D26 in the TR switch.  Page 2 of 4 of the schematic.  The path is very easy to trace if you have a sig gen and scope.  When they go dead, they are dead. 

 

If you have a parts supplier over there you can get the exact part number from Elecraft support.  They are pretty common devices.

 

Ken K6MR

 

From: Vic Lindgren G4BYG
Sent: Wednesday, April 21, 2021 04:39
To: Elecraft-K3@groups.io
Subject: [Elecraft-K3] K3 PIN Diodes blown ?

 

Can anyone help  with my K3 fault
Which PIN diodes are most likely to need replaceing with a no rx fault condition??
Transmitter is good.Just the rx that is dead.
No error messages.
Both Main and Sub rcvrs not working.
Checked seating of plug in boards and patch leads all appear to be seated correctly.
Configuration has not been altered. One day ok next day faulty.
Suspect rf has got into the RX path.
Any help would be greatly appreciated.
73
Vic G4BYG

 


Vic Lindgren G4BYG <g4byg@...>
 

Thanks for your suggestions Ken and will drag out the old oscilloscope and sig genny for further investigation.

Sherlock Holmes Deer Stalker Hat and Pipe at the ready.

73 and Stay Safe.

Vic G4BYG

On 21/04/2021 17:30, Ken K6MR wrote:

Once when my SO2R filters quit working I fried D25 and D26 in the TR switch.  Page 2 of 4 of the schematic.  The path is very easy to trace if you have a sig gen and scope.  When they go dead, they are dead. 

 

If you have a parts supplier over there you can get the exact part number from Elecraft support.  They are pretty common devices.

 

Ken K6MR

 

From: Vic Lindgren G4BYG
Sent: Wednesday, April 21, 2021 04:39
To: Elecraft-K3@groups.io
Subject: [Elecraft-K3] K3 PIN Diodes blown ?

 

Can anyone help  with my K3 fault
Which PIN diodes are most likely to need replaceing with a no rx fault condition??
Transmitter is good.Just the rx that is dead.
No error messages.
Both Main and Sub rcvrs not working.
Checked seating of plug in boards and patch leads all appear to be seated correctly.
Configuration has not been altered. One day ok next day faulty.
Suspect rf has got into the RX path.
Any help would be greatly appreciated.
73
Vic G4BYG

 


Vic Lindgren G4BYG <g4byg@...>
 

Yes will do Henk.

Many thanks for the info.

Just downloaded the schematics from the Elecraft Website.

Will let you folks know how I get on.

Now if only I could remember how to rotate a PDF file 😅

73 and Stay Safe.

Vic G4BYG

On 21/04/2021 17:52, Henk PA0C wrote:
Check the switching voltage on those diodes as well. 
My dead receiver was caused by an open rf-choke while the diodes were still ok.
73 Henk
PA0C


-------- Oorspronkelijk bericht --------
Van: Ken K6MR <k6mr@...>
Datum: 21-04-2021 18:30 (GMT+01:00)
Onderwerp: Re: [Elecraft-K3] K3 PIN Diodes blown ?

Once when my SO2R filters quit working I fried D25 and D26 in the TR switch.  Page 2 of 4 of the schematic.  The path is very easy to trace if you have a sig gen and scope.  When they go dead, they are dead. 

 

If you have a parts supplier over there you can get the exact part number from Elecraft support.  They are pretty common devices.

 

Ken K6MR

 

From: Vic Lindgren G4BYG
Sent: Wednesday, April 21, 2021 04:39
To: Elecraft-K3@groups.io
Subject: [Elecraft-K3] K3 PIN Diodes blown ?

 

Can anyone help  with my K3 fault
Which PIN diodes are most likely to need replaceing with a no rx fault condition??
Transmitter is good.Just the rx that is dead.
No error messages.
Both Main and Sub rcvrs not working.
Checked seating of plug in boards and patch leads all appear to be seated correctly.
Configuration has not been altered. One day ok next day faulty.
Suspect rf has got into the RX path.
Any help would be greatly appreciated.
73
Vic G4BYG

 


Alessandro iw3inq
 



I had a k3 under repair
problem no rx all bands
D5 by KXV3A


73 Alex iw3inq


Vic Lindgren G4BYG <g4byg@...>
 

Thank you Alex for your input and will check it out.

This is the first problem I have had in the 11 years of heavy usage of the radio.

A tribute to the ruggedness of the K3.

Take care and Stay Safe.

Ciao.

Vic

G4BYG

On 21/04/2021 21:26, Alessandro iw3inq wrote:


I had a k3 under repair
problem no rx all bands
D5 by KXV3A


73 Alex iw3inq


C G
 

See:

De: "C G" <f1gwr@...>
Objet: [Elecraft-K3] Weird K3s failure
Date: 26 novembre 2020 à 23:07:22 UTC+1
Répondre à: Elecraft-K3@groups.io

Had around 40 dB less reception than usually. Thought it was some kinda static yielding first transistor failure, or some PIN diode with magic smoke? After tracing the signal from the sig gen connected to the antenna input (--15 dBm being a good value) with a R&S HF millivoltmeter, noticed that D25 PIN diode didn't pass HF. No polarization, and diode direct and reverse testing with multimeter was OK. No short circuit to ground at R48; RFC45 open circuit: 7 V on one lead, 0 on the other. Replaced the latter and off we go: -73 dBm = S9!

Has SO experienced the same failure?

Is this random component failure, or any over-current explained issue?

73,
Christian



Le 20 avr. 2021 à 21:40, Vic Lindgren G4BYG <g4byg@...> a écrit :

Can anyone help  with my K3 fault
Which PIN diodes are most likely to need replaceing with a no rx fault condition??
Transmitter is good.Just the rx that is dead.
No error messages.
Both Main and Sub rcvrs not working.
Checked seating of plug in boards and patch leads all appear to be seated correctly.
Configuration has not been altered. One day ok next day faulty.
Suspect rf has got into the RX path.
Any help would be greatly appreciated.
73
Vic G4BYG


Dan Violette - KI6X
 

Reminds me of our club K3 last year with D5 of KPA3A intermittent.  Found corrosion leaking out of it? and one lead did not look like it was soldered.  Corrosion limited to the one part.  If pictures come through, attaching a couple.  If they do not, ask me if you want the pictures.  Also found R5 was too big for the space it was in and was “tacked in” at an angle.  It was loose some on the end like it was not soldered down fully.  Fixed that with a wire under the end for a “lead” to make it solder better.  Working great again.

 

Dan KI6X


Vic Lindgren G4BYG <g4byg@...>
 

Ok Dan,
Much appreciate your input.
I will check out that area while fault finding. 
73 and Stay Safe.
Vic G4BYG 




On 23 Apr 2021, at 02:26, Dan Violette - KI6X <danki6x@...> wrote:

Reminds me of our club K3 last year with D5 of KPA3A intermittent.  Found corrosion leaking out of it? and one lead did not look like it was soldered.  Corrosion limited to the one part.  If pictures come through, attaching a couple.  If they do not, ask me if you want the pictures.  Also found R5 was too big for the space it was in and was “tacked in” at an angle.  It was loose some on the end like it was not soldered down fully.  Fixed that with a wire under the end for a “lead” to make it solder better.  Working great again.

 

Dan KI6X


Vic Lindgren G4BYG <g4byg@...>
 

Hello folks,
Just a word to all those kind folks who offered their expertise in helping me trace the fault on my Deaf  K3.
As many of you suggested it was D5 on the KXV3 board.
It has been years since I chased and repaired electronic gear. SMD work is very demanding on both a steady hand and plenty of GLIM (Bright Light) .
I found gaining access to the offending board was a real pain and advise anyone attempting to proceed with great caution when dissasembling, Taking notes and photos
while you go is a good help when it comes to putting it all back together.
So it was with great relief when I powered up the radio and it burst into life.
Again many thanks to you all.
Stay Safe and 73
Vic G4BYG