Mark III - Smoke from power switch

[lowercasee]

So I forgot to turn off the power switch on my Mark III last night. Realized it was still on this morning when I went downstairs to the "office/music room" to start working so I switched it off. What I didn't realize is that even though the switch was down, it was still on. After a few minutes I noticed an electrical burning smell. Walked back over the amp and saw some smoke coming from the power switch. I tried to push it down more but no luck so I just unplugged it. Pulled the chassis and I don't think I see any other damage, but I am not sure. Is there anything in particular I need to check? The smell is definitely coming from the power switch, nothing else has that same odor.

Looks like some other members with Mark IIIs and various II series have had similar issues. Based on some posts, it looks like I need a Carling 110-73 switch. Can anyone confirm? Also, would it be advisable to replace the standby switch as well since I'll already be in there? Is it the same switch?

Sorry for all of the questions, just want to make sure I do it right as I don't want to smoke the whole thing. Thanks!

 

[OryCheyne]

Hi,
Sounds like you're on the right track. I can't advise you if the part number you have is the right one or not, hopefully someone can Those switches should be common.
Assuming your old switch went HR and the wires are ok it should be a straight forward swap. If the wires got too hot the insulation may become brittle and crack over time, fall off and leave a hidden danger, like shorting to the chassis.
That power switch does switch at full mains power. No relay, right on the power. I'm not sure whether the same is the case with the Standby. If the switches are prone to failure due to usage then you would think that the Standby switch would have done more cycles than the Main, and therefore suffered more wear. But from your description it sounds like the Main failed after an abnormal event and so that failure is unlikely to effect the reliability of the Standby switch.

Ignore these comments if you know what you are doing, but if you work on electric's only sometimes, then make sure you do it neat, or get a tech to fix it, don't go make the chassis live by accident, and don't ignore damaged insulation on the wires to the switch.

Death by Boogie sounds cool, but I'm guessing the novelty would wear off quick.

Ory.

 

[lowercasee]

Thanks for the tips. I went ahead and ordered the switch from Amazon, should hopefully arrive in a few days. I checked the wires and the insulation seems to be OK and still pliable. While I am comfortable assembling / disassembling things, my soldering skills leave a lot to be desired. I will probably have my brother do that part as he is much more skilled in that area. Can't wait to get it back up and running. Have been using my Vox VT120+ since the Mark went down and it's just not the same.

 

[OryCheyne]

It's good to have back-ups.
Good luck. I hope you're plugging in to your mkiii again soon.

 

[lowercasee]

My switch got here today, along with my soldering kit and some other odds and ends. My brother couldn't stop by until next week and I just couldn't wait that long so I ordered up a kit from Amazon Prime. Pulled up some youtube videos on soldering / de-soldering and figured what the heck... I made a little cardboard shield so as to not drop anything or any hot solder into the chassis and got to work. Not really difficult just nerve wracking because of the small connections. Once I got everything reconnected, I plugged her in and... IT'S ALIVE!!! SOOOO happy to have my Mark III back up and running. The Vox VT120+ isn't a bad backup amp, but it just doesn't have "that" sound like the Mark III does.

Edit: One questions, the 4 screws that hold the chassis in... On one, there is a connector which I'm assuming is a ground. The connector on mine looked like it was completely off so I tried my best to solder the wire back to the hoop. Am I right about this being a ground?