Mark III blue help!!!!!!

[silentrage]

So USPS kicked the **** out of my mark 3, it arrived with the headshell cracked and the rack rail ripped out of one side. (it's a rackmount headshell)
I finally got a speaker today and after testing it out I'm really choked, it seems to be damaged.

First the amp doesn't fire up, I replaced a fuse and got it going.
There are various bits and pieces that seem rather loose in the amp, like a lot of the wiring and some resistors (orange) on the tube sockets, I don't know if it's from the shipping or if it's just old.

The 8 ohm speaker jack is not working, so I'm hooking up the amp with the 4 ohm jack to an 8 ohm speaker right now. It feels really loose so maybe it needs tightening up, I hope that's the case and not something worse.

The amp is making an audible low hum, seems to be coming from the chassis and not the speaker, I've not heard my other amps do this, is this normal?

Also the speaker is doing a pretty audible low freq hum as soon as the amp is off standby and on play. It seems to do it with or without a guitar plugged in, even does it when the master is on 0.

And when I plug a guitar in, the amp is buzzes really loudly on all channels, it only does this when my guitar volume is turned up, and regardless of if I'm playing or not and regardless of whehter I'm touching metal objects, if the guitar volume is turned off then the buzzing stops.

I swapped around all the power tubes, all the preamp tubes in every position, tried class A and simul mode, tried to twist all the knobs, tried playing away from the computer and any appliances, and it's always there.

The really odd thing about this buzzing is that when I switch to piezo, it goes away completely. I thought this meant that my mag pickups wiring is bad. But the thing is I've had this wiring for months now and I've played through my dc-5 and peavey rockmaster without any buzzing whatsoever. I whipped out the peavey today to see if it buzzes with the guitar and it doesn't, so what's the deal here? I'm positive there's nothing wrong with my wiring to produce that much buzz, and even if it's a guitar wiring thing, the buzz should go away when I touch metal.

I'd really like to try to diagnose this myself first before taking it to a tech due to finances so help is greatly appreciated.

 

[Restless Rocks]

The power transformer is held to the chassis with four bolts. There is a braided ground wire attached to a star washer under the nut right next to the main Circuit board. Since your amp got severely jacked around there is a good chance this nut is loose causing a bad ground connection to the main circuit board. But seriously if you have "stuff" shaking around inside the chassis I would highly recommend taking it to a tech for a look over, your troubles could just be beginning if you have broken parts and loose wires. Then I'd go looking for the buttmunch that shipped it.

 

[silentrage]

I'll look at the grounding wire bit.
I looked at the amp some more it seems the loose parts are the inner portions of the power tube sockets, they're still connected to their respective wires and resistors and such, they just sit loosely in the tube socket, is that an old age thing or being dropped from 6 feet repeatedly thing?

 

[silentrage]

I checked out all the grounding wires I could find, and they're all ok.

However there is a component that seems to be broken, but I"m not sure what it is.

It's a green thing, flat and round shaped, sitting right on top of the fuse holder.
When I put the 2 jacks on the 2 legs of this component, I hear a rapid succession of beeps, sounds the same as a cold solder joint.

Any idea if this could be the cause?

I don't have a camera so I stole some one else's chassis pic, but it's in the lower left corner.
http://img.photobucket.com/albums/v432/RussBert/MKIIIchassisstock.jpg

 

[silentrage]

Can someone recommend a good amp repair guy near Toronto?
Preferably not L&M or Steve's as they take a long time.

 

[Monsta-Tone]

That fucking sucks!

This is exactly why I've become a shipping nazi with the amps that we receive.



The green thing sounds like your MOV, which is a surge suppressor device.
Since you are already messing with it while the amp is on, I will say that I hope you are using a non-conductive plastic rod or chop stick!
Does the amp make this noise when the parts are pulled apart?
Don't shock yourself, it really hurts!


Also, the pins on the power tube sockets will sometimes rattle if there are no tubes installed.

If the amp hums when it's on Standby, it's usually a transformer issue.
If the amp hums when in Play, but with no guitar volume, then it's usually a capacitor or resistor issue.
If the amp hums when the guitar is turned up, then it usually is a ground or pot issue.

I'm not sure about who is around you, but you could call Mesa and ask them. They are closed tomorrow though, so you would have to do it today.

 

[silentrage]

So things have taken a turn for the better. I'm getting normal operation mostly now, the only problem is loud feedback/ oscillation when 1. R2 is pulled, lead is pulled and on exactly 10, and lead master pulled.
If any of those 3 are not true, it sounds normal.
Anyone?

 

[bryan_kilco]

man, that really sucks. I got my IV, used, off Ebay, and it arrived in a crushed up box, with power tubes shipped IN the sockets...all broken....they sent extra tubes (used)....i called the guy, he said he'd work something out (we had insurance and all, got NOTHING out of the deal....)

amp still doesnt work 100% and I need to get it fixed asap.

 

[Monsta-Tone]

man, that really sucks. I got my IV, used, off Ebay, and it arrived in a crushed up box, with power tubes shipped IN the sockets...all broken....they sent extra tubes (used)....i called the guy, he said he'd work something out (we had insurance and all, got NOTHING out of the deal....)

amp still doesnt work 100% and I need to get it fixed asap.

Let me know if you can't find anyone locally.

 

[silentrage]

I found that the oscillation changes a bit when I tap on the yellow wire coming off the middle tab on the lead drive pot...