Problem with Lonestar Special- No Sound

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Reggiedadog

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HI, all, new to MB and this forum so first post here.

Ordered a used LSS which arrived last week (was send a few hundred miles by courier though appeared well packed) after trying them new in several stores.

Played it constantly for last 4 days with no issues. Love it.

Then tonight no sound at all, did normal troubleshooting (leads etc) Made sure all knobs are on 12 just in case and found I can get a sound when plugged into Return on the fx loop, but it is pretty flat. So Im guessing this is a pre amp issue- am I missing something?

Not very technical so you might want to type slowly so I can keep up

Thanks

R
 
Need more info.
Do the tubes glow?
Be sure ALL the filaments glow.
If even one goes bad it can make the whole amp fail.
 
If all the tubes glow the next step in the process of elimination is to check the loop.
Run a jumper through the loop.
Just take a 6" pedal patch cord and plug one end into the send and the other end into the return.
If the amp starts to function then the contacts could need cleaning or the jacks may need replacing in the loop.
 
If that doesn't solve it get another preamp tube that you know absolutely to be good.
Remember that just because it is new doesn't mean it is good.
Sometimes a brand new tube is faulty right out of the box.
You need to know for certain it is good.
Try it in another amp or borrow one from a working amp.
Try substituting the good one in place of each preamp tube, one at a time and test each time.
 
Please be careful in there.
If any of this sounds foreign to you or it seems like you're in over your head then stop immediately and take the amp to a pro.
 
Thanks buddy, yes all the tubes are glowing although one on the far left (when looking at back of the amp) is not as bright as the others,

The amp isn’t new it was used, so Ive no idea when tubes were last changed. I couldn’t afford a new LSS they are a fortune over here!
 
There are (10) tubes in your amp.
(4) EL84 power tubes
(1) Rectifier tube - typically a 5Y3
(5) Preamp tubes - usually in the 12Axx family, most often 12AX7.

Make sure you have looked at all of them.
You should be able to tell which ones are which because of the quantities I've just given you.
All the power tubes will look the same, so (4) of those, etc.
The rectifier should be a little bigger than the power tubes.
The preamp tubes should be a bit smaller.
The one closest to you on the far left should be the rectifier.
If it is not glowing as brightly as the (4) power tubes that may not be a big deal.

To start with you should be first concerned with the preamp tubes.
They are further inside and could be hidden from your sight with the back panel in place.
You could start by removing the (4) Phillips screws that hold the rear upper panel in place and removing that panel to improve your access and visibility.
It is a wooden panel with a curved cutout and it is covered with brown tolex.
It has a slot cut into it for the speaker cable.
Remove that panel being carful not to be rough with the amp.
Be careful as tubes get pretty hot.
If all the preamp tubes look equally bright and the loop test didn't fix it then you may have to see a professional.

You didn't by any chance happen to unplug the speaker?
 
Don't worry too much about being a novice at this point.
All you're doing is removing wooden panel and having a look.
I'm not going to ask you to perform brain surgery.
We're just having a look to see if it might be something simple that you can do yourself.
 
Thanks for your help- the speaker must be fine because when I plug into the effects return I get a sound.

I have borrowed a 12ax7 off a buddy, so will remove the back later and take a look at the preamps- I suspect the tubes haven't been swapped in forever so I am hoping it is this.

Will report back later!
 
BMW-KTM said:
Don't worry too much about being a novice at this point.
All you're doing is removing wooden panel and having a look.
I'm not going to ask you to perform brain surgery.
We're just having a look to see if it might be something simple that you can do yourself.

Hi ok so I took the back off and removed those steel cyliners around the preamps so \i could see them

Not one of the pre amp valves are lighting up, so Im guessing the problem must be something else?

Rich
 
We have arrived at an outcome that is beyond your abilities as a novice and beyond my abilities to walk you through this any further.
Put everything back as you found it and take it to a good amp tech.
I said good, not the closest or the cheapest.
There often quite a few hacks in any given town that can't be trusted beyond tube changes, jack replacements and biasing.

The easiest to find and possibly speediest tech will be a factory authorized MESA/Boogie repair depot.
Please note I did not say authorized retailer, I said repair depot.
There's a huge difference.

If there is no authorized MESA/Boogie repair depot within striking distance of your town there is another way to find a highly respected amp tech who knows his stuff.
Track down a local lighting and sound company that contracts out to concert promoters in your area and builds the stages for the big acts when they pass through.
If anybody will know who the best repair guys are in your area, they will.
 
1. Switch off the fx-loop, there’s a small toggle switch on the back panel for loop in or hard bypass ! Any difference ?
2. Plug guitar lead into fx send and then adjust channel volume, not the master volume! Any difference ?
3. With the amp on at reasonably high levels, turn up the reverb levels to max, and nudge the amp ! Can you hear the Spring Reverb ?
4. If you’re getting yes to the above, with it unplugged, and as explained in removing the top back panel. Unplug from the mains, amp off, carefully remove the metal shrouds from all preamp tubes. The one nearest the fan is a little awkward t . . t
Remove V1, it is furthest from the back and furthest from the fan. It is likely you’ll have to remove the power valves/tubes, as they can get in the way. Place the removed somewhere flat and safe and note which were which.
Substitute V1 with V3 ( that’s the valve next to the fan)
Reassemble except for V3, put the fx-loop in hard bypass and then plug into the frontend and check for levels on only the channel volume controls, and obviously the tonestacks !
Any difference?
None of the above involves high voltage, just clean hands and care with the glass, and care when reinstalling the valves so as not to bend the pins. Don’t worry, go slowly, methodically, and it will give you confidence.
ps. When plugged into the fx send you will be using the master volume, and assuming you get volume then V3 can be used for V1
All that, the first time, will be as clear as mud, don’t worry, it’s a learning curve and you are not entering the danger zones.
EVERYTHING WITH MAINS OFF, EXCEPT WHEN DOING YOUR SOUNDCHECKS

If anything isn’t totally clear, or slightly confusing then ask, I did do my response during the small hours on my meds. But they are easy steps without risk to life limb or amp, and you’ll understand it more. Maybe, at worst you may have to purchase a couple of preamp valves

Wednesday morning . . A correction now my meds have worn off ! When plugging direct into the fx send, use the master volume to check the power stage with the “Hard Bypass” switch on.
Try the various power settings on the 3-way switch
 
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