Splawn Quick Rod - No sound from preamp and footswitch not lighting up

[Nitrobattery]

I was hoping some of you have run into this problem before and may have an answer. I have a 2009 Splawn Quick Rod and I fired it up today to do a session and the lights were on but nobody was home. I get signal if I plug into the effects loop return, but the preamp isn't working and the footswitch isn't lighting up either (removing the footswitch cable doesn't remedy the problem). I went down the line and swapped out the preamp tubes but that didn't help. I was curious if any of you techs have run into this before and could offer some insight. I'm fairly handy with a soldering iron so if it's a part/repair that I could do myself that would be awesome. Thanks!

 

[harddriver]

Could be a switching relay gone bad.

 

[311boogieman]

I was hoping some of you have run into this problem before and may have an answer. I have a 2009 Splawn Quick Rod and I fired it up today to do a session and the lights were on but nobody was home. I get signal if I plug into the effects loop return, but the preamp isn't working and the footswitch isn't lighting up either (removing the footswitch cable doesn't remedy the problem). I went down the line and swapped out the preamp tubes but that didn't help. I was curious if any of you techs have run into this before and could offer some insight. I'm fairly handy with a soldering iron so if it's a part/repair that I could do myself that would be awesome. Thanks!

Seems like a tough one. Assuming you swapped V4 too? You know it is safe to pull a preamp tube while live? Though I wouldn't always recommend that you could turn it off, take out V1, turn it on, play, turn it off, V1 back in, take V2 out, repeat. Right @harddriver?

Are you sure you are not stuck on the clean channel? What happens if you patch the loop?

 

[reignman454]

I was hoping some of you have run into this problem before and may have an answer. I have a 2009 Splawn Quick Rod and I fired it up today to do a session and the lights were on but nobody was home. I get signal if I plug into the effects loop return, but the preamp isn't working and the footswitch isn't lighting up either (removing the footswitch cable doesn't remedy the problem). I went down the line and swapped out the preamp tubes but that didn't help. I was curious if any of you techs have run into this before and could offer some insight. I'm fairly handy with a soldering iron so if it's a part/repair that I could do myself that would be awesome. Thanks!

Footswitch plugged in? Remove it and try if so. As 311 mentioned, tube could be an issue. Did the 09 have the manual selector for gears or channels? Change ONE thing and try it IE:

Unplug footswitch, flip switches, no fix? move on.
Swap V1, flip switches etc, no fix? Move on.


I have 5-6 splawns including quickrods, haven't had this issue.


P.S.,

Gigged hard? Studio queen? How recent are the tubes?

 

[Toneboner]

What happens if you patch the loop?

Id patch the loop. Pretty sure '09 has the push button loop bypass switches. Perhaps the button is toast but stuck "on" so you'll not get signal without a patch or other device providing continuity.

 

[Nitrobattery]

Went down the line and swapped each preamp tube. Doesn't work when the footswitch cables are disconnected and every gear is having the same issue. I do get signal when plugged into the effects loop return. I was in the middle of shooting a product demo where I had already used it for half of the video, so I ended up bring it to Fuchs which is 30 minutes from me. I'll report back what the issue was.

 

[jasonP]

It sounds like one of the switching optocouplers possibly went bad or possibly what is powering them, could take a meter and see if it's switching, turning on and off or jump the signal side of each one to see if amp passes signal to the power amp.

 

[Toneboner]

Must be nice to have fuchs down the road...

 

[glpg80]

12V rail is dead? He likely uses the same voltage for relays as he does heaters just as a wild guess.

Let us know what he finds!

 

[Nitrobattery]

It was a bridge rectifier. Dropped it off on Thursday and it was done on Monday. They're the best.

 

[harddriver]

It was a bridge rectifier. Dropped it off on Thursday and it was done on Monday. They're the best.

Thanks for updating us about it. This will help others if they have a similar situation in the future.

 

[Toneboner]

It was a bridge rectifier. Dropped it off on Thursday and it was done on Monday. They're the best.

Then How were u still getting audio out of it at all??

 

[fusedbrain]

Then How were u still getting audio out of it at all??

It sounds like it was the rectifier for the low voltage power supply to the relays, not the main diodes for the tubes etc. Thats why the power amp still worked when plugging into the fx return.
Many times, when you power up an amp without power to the relays, the relays will sit in "neutral" and not pass any sound at all, so the preamp will appear to be dead.
If the low voltage supply also supplies DC to the preamp tube heaters, then you're really in trouble lol!
Glad you got it sorted