I will try that, thanks

Hello, I have this Fender Delux 90, type PR402. Does anyone have any history on this amp. It just went to a hum and there was a burning smell, As I was about to shut it down the audio came back on, I still shut it down. I have electronics repair background so I opened it up and can see nothing burned on the circuit board. The fact that it came back on indicates to me that the output transistors
are good, the only other thing that makes sense to me considering no visible charring on the circuit board is the transformer is burning. At the time when I was playing I was not pushing the volume, I was under 2 in the clean channel  with a Boss GT10 effects board hooked up with heavy OD distortion.
Any help is appreciated
Don

The "Kazoo" effect was bothering me and made me think (Blown Speakers??) so I plugged in the headphones and the guitar sounds good, nice & clear, small hum in the OD channel but not bothersome I'll hunt down that problem later. Can anyone concur? Bad speakers?

Trying to attach schematic

Hello I have a Solid State Marshall Valvestate VS230 that I need help with, I do have the schematic. It started with a high pitched "pop" when powered on, but it would play fine. Then it developed a squeal. I have electronics background so I opened it up and found 2 resistors had gotten hot and turned brown. R10 and R18 both 10 ohm 1/2w, I replaced them along with 2 2.2uf/50v caps in the circuit and the 2 power output IC's TDA2050. But it got worse instead of better, now it sounds as if Im playing through wax paper much like a kazoo. If anyone knows about solid state amps and what could be the problem here, any help is appreciated. I can email you the schematic if you like.
Don

Quote from: J M Fahey on June 05, 2011, 10:31:28 AM

Quotesimilar to hearing when a drill or blender is being used

Well, *maybe* a drill or blender *is* being used somewhere close and you don't know it.
Computers, TVs and monitors, not excluding switching power supplies (which are everywhere, such as your Cellphone charger) and even Cellphones themselves, which regularly chirp "I'm here" to nearest tower, all contribute to electrical noise.
Something funny that happened to me: I live in La Boca, the ancient Buenos Aires port , less than 100 meters from the waterline.
Once, at different times of the day, I heard *everywhere* (even on my TV and my phone) this "... zzzt ... zzzT ... ZZZT ... click click click ... ZZZT ... zzzT ... zzzt ..." sound.
It was maddening.
A shipowner neighbour visited me, and when he heard it said "are you repairing a Marine Radar .... ?"
Turns out there was this Spanish fishing ship anchored one block away, which was being repaired, testing illegally their Radar.
They have a high power setting for navigation use and a low power one for port use.

I only use the drill and blender thing as an example, the sound is simlar. however my pc is on as I use it to practice with, I use jam tracks. And altho we are on an island we are miles from any port.

Quote from: phatt on June 05, 2011, 06:34:05 AM
Does it happen at the same time every day?

Phil.

No, not same time. random.

I have a solid state Marshall Valvastate VS230, works and plays fine except sometimes inbetween songs it makes this whining sound, it's hard to explain but when nothing is being played, no effects plugged in just straight guitar with a known good cord it makes this sound, similar to hearing when a drill or blender is being used over an AM radio but there is nothing being used. The sound will appear then sort of break up then go away. Im a tv repair tech so if this is something where all I need is a resistor or a cap or IC I can do it myself, I looked at the circuit board and nothing looks burnt and solder joints all look good. Anyone know what this is?