MARK III REVERB PROBLEM

[jay]

I HAVE AN 86 MARK III SIMULCLASS BLACK DOT SHORT HEAD WITH GRAPHIC EQ AND REVERB. WHEN I TURN THE REVERB KNOB UP TO 10, I CAN BARELY HEAR ANY REVERB. I TOOK THE REVERB UNIT OUT AND TRIED IT IN MY FRIENDS MARK IIC+ AMP AND IT WORKED FINE. I CHANGED THE PREAMP TUBE IN MY HEAD THAT DRIVES THE REVERB WITH NO CHANGE. EVIDENTLY THERE IS SOMETHING WRONG INSIDE THE HEAD. I ALSO TRIED THE FOOT SWITCH FOR THE REVERB WITH THE SAME RESULTS. THE EQ SWITCHED FINE BUT THE REVERB WAS STILL FAINT. YES I USED A STEREO CABLE. ANYONE HAVE AN IDEA WHATS HAPPENING? DO I NEED TO SEND IT TO BOOGIE OR IS IS AN EASY FIX?

 

[Joey707]

You should clean the connectors on the amp and the tank. Test the cables. You might also take a look inside the amp and make sure nothing has come loose. Check around the reverb pot, the RCA connectors that are mounted to the chassis, in and around the reverb tube, etc. It is also possible that the reverb transformer has gone bad. That's kind of rare but it can happen. There is a way to test the reverb transformer, but I can't remember what it is. Maybe some else can help with that.

 

[jay]

thanks for the info. i will check it out and see if this fixes the problem.

 

[jay]

i fixed the problem. i took a screw driver and touched it to the tank and to the side of the rca jack and the reverb worked. i will either get new cables or try to fix these. it was on the input side of the tank.i could rub the springs together and hear them but no reverb so i knew it had to be on input side. if other guys having problems try new cables or make sure your connections are good.

jay

 

[Boogiebabies]

Your reverb input should be grounded to the chassis. In most boogies Mesa used a Zinc washer that oxidizes and loses the ground connection. Instead of replacing the washer or shelling out for new cables, you can solder a jumper wire to the grounds from the cable connectors that plug into the amp. This connects the ground with the tank and usually fixes the problem by allowing the circuit to find its way to ground.

What you probably did with the screw driver was create a ground circuit.