Bugera 6262 Infinium head problem (no amplified sound)

[Vampiric113]

Hi,

I've got a problem with my Bugera 6262 head.
I've got him for like 6 months now and its always been working perfect like it should, but ow today i was playing guitar and suddenly my amp stopped working.
When i plug in my guitar and keep playing on the lead channel it sounds like the sound of my guitar isn't amplified anymore so the volume is really low and the volume or gain control doesnt affect it anymore.
On the clean channel i don't even get any sound anymore and if i push the "bright" button, the light of that button also won't light up.
The tubes are still glowing, so i assume thats not the problem.

Does anyone has any idea what the problem could be? I really need to fix it before the weekend since i got a show with my band.

[mozwell]

Not sure if this is the Infinium model, buts its a 6262
Hope this helps

First step, check any internal fuses - are they still ok, F1 2A fast blow, F2 1A slow blow, F3 1A slow blow, F4 10A fast blow

Second step, measure power supply rails & report results here, this includes HV power supply V3+, V2+, V1+, +24V, -24V, +15V, -15V, don't forget X21 Bias voltage

Third step, if there are connectors or spade lugs, check these are all pushed on correctly.

Fourth step, plug a guitar lead between FX send & FX return. These have internal switching contacts which can get "bad" after a while, ready the sticky note at the top of this forum "the dreaded switching jack problem"

[Vampiric113]

Yes its the infinium model, i don't have much skills in repairing or opening a guitar tube amplifier, but i've got some basic knowledige of electronics, so i'll check out the fuses first.

[Vampiric113]

On a first look it doesn't look like any fuses are blown, or would it be best to measure it to be sure?

[52 Bill]

Do you have an ohmmeter? If you do have a meter, remove and replace the fuses one at a time and test them with your meter.

[drewl]

Plug into the FX return, any sound?

Any signal from the FX send?

[oc disorder]

Vampiric113 A belated "Welcome to the forum" ...

Firstly I would beg , borrow , or hire a backup to take the pressure off.
I presume it's out of warranty which should be the first step.
If the fault is not the efx loop or the fuses or something simple
you can deal with I would suggest taking it to a tech who "knows his stuff" !
I mean you wouldn't get a "guitarist" to step in for you with only a couple
of days experience on some forum !!

There are lethal voltages inside and I don't think your band or your relatives for that matter,
would be too impressed with this forum if you failed to turn up for the gig for the worst possible reason !!!

I had a 333XL recently , the pwr amp schematic looks remarkably similar.

Mozwell mentioned " if there are connectors or spade lugs, check these are all pushed on correctly" and I would add -
examine them closely for any signs of heat..particularly the connector from the power transformer near the fuses.

The 333xl had one led that was not working this was a separate fault and not related
to the amp not working. Yours may be different.

I found that R62 the big ceramic 10 watt resistor 390Ω had disintegrated
and needed replacement.It connects to the standby switch and supplies the screens.

If the amp has been switched off for a while so the capacitors have discharged
you should be able to measure the resistance of R62 to see if it's still ok.

From memory there is about 460vDC at that point so maybe set the multimeter
to DC volts (1000?) and with the black probe on the chassis (shiny screw?)
touch either end of the resistor with the red probe and make sure there is no voltage there before
measuring the resistance.

That's my 2 cents worth!