Hi everyone,
I’m having an issue with my CQ-18T. Input channel 8 has become unreliable. When an XLR cable is plugged in, the signal cuts in and out if the connector is slightly moved or wiggled. Even very light contact during a live set can cause the signal to drop completely.
This has happened multiple times during performances, so the channel is currently unusable for critical inputs.
The cable has already been tested and confirmed working on other channels, so I’m confident it’s isolated to Input 8. Based on the behavior, I suspect it could be:
- A cracked/dry solder joint on the XLR connector
- A loose XLR socket
- Possibly a fractured PCB trace near the connector
I have basic electronics and soldering experience (I build my own cables and have done minor board repairs before), so I’m comfortable opening the unit if necessary. However, I’d appreciate advice before doing anything that could make it worse.
Has anyone experienced this on their CQ-18T?
Is this a known issue?
Is reflowing the XLR solder joints usually enough to fix something like this?
Are there specific things I should watch out for when opening the unit?
If anyone has a teardown video of the CQ-18T, that would be extremely helpful so I can see what’s inside before opening it myself. A service diagram or internal layout reference would be amazing as well.
Sending it to the service center will take time and significant shipping costs, so I’d like to assess whether this is something manageable first.
Any guidance would be greatly appreciated. Thanks in advance!
Since the introduction of RoHS (Restriction of Hazardous Substances), solder does not contain lead anymore, and is way harder than it used to be. Cracks are way more common with lead-free solder.
So, a reflow (with leaded tin!) might fix your issue … but I can’t judge it through the internet.
I was able to open the unit and I think the issue might be on the socket itself since I don’t see or at least feel any cracked/dry solders. Here’s a picture of input 8, let me know what you think.
I’d reflow it anyway; not all cracks are visible to the human eye.
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After reading your post I understand that your have test the XLR cable to the other XLR inputs with succes.
I might be wrong but your testing process is missing a test of the input 8 with another XLR cable.
That would point or eliminate a physical faulty of the XLR input (corroded or faulty fitting pin) and you’ll know if this is 100% electronic issue.
Beside this, looking at your picture, the left point solder look to me not perfect.
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Agreed with above.
Appears to be a crack at the top of the solder point to the left of PCB marking C71_8
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And in any case, follow this very good advice 
Thanks for the replies, I really appreciate the help.
I gently moved the connector and checked the joints visually, and I couldn’t see any obvious cracks or broken solder points.
I was hesitant to reflow the solder right away because I’m worried I might accidentally affect nearby components and cause more damage. My soldering experience is fairly basic. I mainly build my own cables and have done small repairs on things like computer mice and guitar pedals.
I also tested multiple XLR cables during troubleshooting and can confirm the issue only happens on Input 8, so I’m confident it’s not a cable problem.
If I were to attempt reflowing the solder joints, do you have any advice on the safest way to approach it? I want to minimize the risk of damaging the board or nearby parts.
At the moment I only have:
- a soldering iron
- standard solder
Please let me know if there are other tools or precautions I should consider before attempting this. Any guidance would be greatly appreciated.
Also, here’s another photo for reference (This one had flash on).
