Deluxe Reverb Weak Output

[nikdvs457]

I have a Fender Deluxe Reverb (the stamp inside says 1972) that was working great until one day while I was playing, the volume cut way down and wouldnt turn up past barely audible. A change of tubes didnt solve the problem, so I changed the electrolytics (suspecting the cathode capacitors from this list). After this, the amp worked for about 10 to 15 minutes and cut way down again. I could pull out the preamp tubes, and reinstall them, and it would work for another 10 to 15 minutes. Today I was doing some more troubleshooting, and that didnt seem to be working anymore.

Does anyone have any theories as to what's causing this? Any help or idea is sincerely appreciated.

[Bruce / Mission Amps]

Check top see if the 47 ohm to 100 ohm resistor at the end of the phase inverter section...under the 22K-27 tail resistor in a schematic... has come ungrounded... this happens quite a bit to old Fender amps.
Actually pull on it as the solder looses it's grip on the lead.
The other thing is the wire that goes to the brass plate from this same spot, pops off the brass plate frequently.

[nikdvs457]

No, everything seems to be good there. All the connections to the brass plate are solid as well.

[acorkos]

I have a Fender Deluxe Reverb (the stamp inside says 1972) that was working great until one day while I was playing, the volume cut way down and wouldnt turn up past barely audible. A change of tubes didnt solve the problem, so I changed the electrolytics (suspecting the cathode capacitors from this list).

"Open screen resistors on power tubes "

[Bruce / Mission Amps]

And let's not forget the obvious things like a shorted voice coil, shorted output jack and another common malady, filament voltage loss due to bad, cold or old solder joints on the tube sockets... etc.

[Amp Kat]

You can look at the tubes from the back while playing to see if the filaments are dropping out when it looses sound. If that's not it your going to have to do some checks to find out what's dropping out,voltage or signal. If you monitor plate voltage,bias voltage and heater voltage and it doesn't drop out then it's most likely signal dropping out which would seem like a connection problem and you'd most likely need a scope to find it. But it sounds like filaments dropping out IMO.

[Josephcarassojunior]

Hi, did you find the causr for this problem?