A stab in the dark-- Try reheating the connections to the low pass filter to burn off any remaining enamel.

The intermittent operation suggests that something (maybe temperature) is activating a flaky connection.

Good Luck!

73, Paul -- AI7JR

On 8/21/23 09:40, Arlen Levin wrote:

I recently completed assembly of a QCX mini 30m version. It worked on first power up, although the power output was a little low.
I took it on a camping trip a week or 2 later and on first attempt, there was no power output. I tried again a few hours later and it was working again.
The next day, same issue, no power output and was not able to get any power output since.
When keying, I hear the side tone and also receive seems to be active. I don't remember if this was the case or receive gets muted on transmit.
So, my question is, do I have a problem with transmit/receive switching or power output and anything else to check before removing from case?
I did try a factory reset.

Tnx,
Arlen Levin
WA6AUF

Thanks for the suggestion, but looks like I have other issues. I took the unit out of the case and powered it up. Noticed that Q1 and Q6 got hot pretty fast.

With a 12v power supply, I am drawing about 150 ma without the display and control boards attached. I guess that is a little high.

Don't see any solder bridges or anything else abnormal. Anyone have any ideas where to look?

Arlen

WA6AUF

On Mon, Aug 21, 2023 at 12:30?PM Paul - AI7JR <paul.hanchett@...> wrote:

A stab in the dark-- Try reheating the connections to the low pass filter to burn off any remaining enamel.

The intermittent operation suggests that something (maybe temperature) is activating a flaky connection.

Good Luck!

73, Paul -- AI7JR

On 8/21/23 09:40, Arlen Levin wrote:

I recently completed assembly of a QCX mini 30m version. It worked on first power up, although the power output was a little low.
I took it on a camping trip a week or 2 later and on first attempt, there was no power output. I tried again a few hours later and it was working again.
The next day, same issue, no power output and was not able to get any power output since.
When keying, I hear the side tone and also receive seems to be active. I don't remember if this was the case or receive gets muted on transmit.
So, my question is, do I have a problem with transmit/receive switching or power output and anything else to check before removing from case?
I did try a factory reset.

Tnx,
Arlen Levin
WA6AUF

Hi Arlen. what is the current draw on transmit? If Q^ is heating up fast then it's probably?conducting into a short. If Q1 is really hot, it could be the short. You could try replacing that one BS-170 and see if it fixes it.?

The receiver should mute during transmit and only be active in receive mode. Please verify that is the case. It wasn't clear in your note. In receive mode with antenna connected are you hearing signals? If not, the sudden disappearance of power output could be related to an intermittent ?soldering issue on the toroids in the lowpass filter section, which would also potentially damage the final transistors. You should check the continuity?through?the lowpass filter before transmitting again.?

Good luck ... Ron

On Tue, Aug 22, 2023 at 1:42?PM Arlen Levin <wa6auf@...> wrote:

Thanks for the suggestion, but looks like I have other issues. I took the unit out of the case and powered it up. Noticed that Q1 and Q6 got hot pretty fast.

With a 12v power supply, I am drawing about 150 ma without the display and control boards attached. I guess that is a little high.

Don't see any solder bridges or anything else abnormal. Anyone have any ideas where to look?

Arlen

WA6AUF

On Mon, Aug 21, 2023 at 12:30?PM Paul - AI7JR <paul.hanchett@...> wrote:

A stab in the dark-- Try reheating the connections to the low pass filter to burn off any remaining enamel.

The intermittent operation suggests that something (maybe temperature) is activating a flaky connection.

Good Luck!

73, Paul -- AI7JR

On 8/21/23 09:40, Arlen Levin wrote:

I recently completed assembly of a QCX mini 30m version. It worked on first power up, although the power output was a little low.
I took it on a camping trip a week or 2 later and on first attempt, there was no power output. I tried again a few hours later and it was working again.
The next day, same issue, no power output and was not able to get any power output since.
When keying, I hear the side tone and also receive seems to be active. I don't remember if this was the case or receive gets muted on transmit.
So, my question is, do I have a problem with transmit/receive switching or power output and anything else to check before removing from case?
I did try a factory reset.

Tnx,
Arlen Levin
WA6AUF

Ron,

Receive current with all boards installed is about 160ma, transmit 250ma. The receiver is not muting during transmit.

I double checked the toroids and there appears to be good continuity on them. Any voltages I can check on Q1 and Q6 or somewhere else?

Tnx

Arlen

On Tue, Aug 22, 2023 at 4:19?PM Ronald Taylor <wa7gil@...> wrote:

Hi Arlen. what is the current draw on transmit? If Q^ is heating up fast then it's probably?conducting into a short. If Q1 is really hot, it could be the short. You could try replacing that one BS-170 and see if it fixes it.?

The receiver should mute during transmit and only be active in receive mode. Please verify that is the case. It wasn't clear in your note. In receive mode with antenna connected are you hearing signals? If not, the sudden disappearance of power output could be related to an intermittent ?soldering issue on the toroids in the lowpass filter section, which would also potentially damage the final transistors. You should check the continuity?through?the lowpass filter before transmitting again.?

Good luck ... Ron

On Tue, Aug 22, 2023 at 1:42?PM Arlen Levin <wa6auf@...> wrote:

Thanks for the suggestion, but looks like I have other issues. I took the unit out of the case and powered it up. Noticed that Q1 and Q6 got hot pretty fast.

With a 12v power supply, I am drawing about 150 ma without the display and control boards attached. I guess that is a little high.

Don't see any solder bridges or anything else abnormal. Anyone have any ideas where to look?

Arlen

WA6AUF

On Mon, Aug 21, 2023 at 12:30?PM Paul - AI7JR <paul.hanchett@...> wrote:

A stab in the dark-- Try reheating the connections to the low pass filter to burn off any remaining enamel.

The intermittent operation suggests that something (maybe temperature) is activating a flaky connection.

Good Luck!

73, Paul -- AI7JR

On 8/21/23 09:40, Arlen Levin wrote:

I recently completed assembly of a QCX mini 30m version. It worked on first power up, although the power output was a little low.
I took it on a camping trip a week or 2 later and on first attempt, there was no power output. I tried again a few hours later and it was working again.
The next day, same issue, no power output and was not able to get any power output since.
When keying, I hear the side tone and also receive seems to be active. I don't remember if this was the case or receive gets muted on transmit.
So, my question is, do I have a problem with transmit/receive switching or power output and anything else to check before removing from case?
I did try a factory reset.

Tnx,
Arlen Levin
WA6AUF