DC-2 Gets Really Hot???????????

[Monsta-Tone]

I just got a DC-2. I bought it on Ebay as a project. The guy said that his tech told him it needed a new Output Transformer.

I think it has other problems, but I'm not sure what they are just yet.



Here is what the amp does, maybe some of you guys out there have had these same problems:

1. If the amp hasn't been plugged in for a while, or hasn't been turned on for a while (over 2 hours), it makes a very slight short circuit noise when the Power Switch is 1st turned ON.

The amp is in Standby, and I cannot get it to make the sound more than once.

I am thinking it's the 1st Filter Caps or the Bias Supply.

2. The amp gets really hot. I played it at really low volume (baby asleep in the next room), for about an hour. Mostly on the Clean channel.

When I turned the amp OFF, the back of the Chassis where the vents are was very hot.

The Power Transformer was so hot that I could not touch it.




The amp has some older Mesa EL-84's. I tried JJ's in it and it still got hot, but I did not play it as long with the JJ's, so it did not get as hot.

It has been modded. All of the Grid Resistors for the Preamp Tubes have been changed to Carbon Comp (which leads to problem 3, crackling Resistors), and there are several bad solder connections. None of the solder connections look cold, just sloppy.
There are lots of burns on Wires and Relays, etc.


I fix amps as a side business, so I know what I'm doing most days, but I'm unfamiliar with this amp and don't want to go looking for something that isn't there, concerning the heat issue.


Any help would be greatly appreciated. This amp sounds really good, I would like to get it up & running at full speed.

Andy

 

[Monsta-Tone]

Oh yeah, I forgot to mention. I tried the jumper cable in the Loop. This did not fix the crackling Resistor sound.


The circuit board says 1993.

It is the model without the EQ.

It has "Contour," which I think is footswitchable, but I'm not sure.

All functions work on the amp, Reverb, Loop ( I think ), all knobs, etc.

 

[Monsta-Tone]

I figured it out.

The Output Transformer was arcing internally, but only at loud volumes. At lower volumes, it would not do it.

I also found 4 microphonic 12AX7's.

After replacing the transformer (with a Mojotone-Heyboer ) and all of the Carbon Comp resistors and crappy tubes, the amp screams.


Now I only have 1 problem.

When the Power Supply Filter Caps are discharged, the amp will make a short circuit noise the 1st time the Power Switch is turned on. The original problem 1.