Mark V slow to power up - bad transformer???

[G.I.G.]

Hey All,

I've been having a difficult time troubleshooting an issue I've been having with my Mark V head. I've done some searches here and on the net but haven't had much luck. I've already talked to a tech at Mesa in Petaluma but he wasn't able to offer much guidance other than suggesting sending it back to them. I'd like to avoid that if it is something I can troubleshoot and possibly fix on my own.

The problem I'm having is that when I turn my amp on to warm up, it is extremely slow to power up, and it's getting slower. The power light slowly starts to glow brighter, the fan slowly comes up to speed, and the relay switches are clicking for sometimes up to 30 seconds. Once it is at full power, it seems to sound fine. My first thought was that the power tubes were going bad, but I wouldn't think that would affect how long it takes to power up. Not to mention, I don't experience any issues once it comes up to full power. The tech at Mesa said it was probably a line voltage issue with the outlet I was plugged into, but my Recto's are plugged into the same outlet and they power up fine. Not to mention, I am running them through a Furman surge protector and line conditioner. It is indicating a constant 120V coming in from the wall.

I noticed someone else here had a bad transformer. For an amp that is relatively new (I've only owned for 2 years and it has been used sparingly) I would find it hard to believe that the transformer is bad, but that is the only thing I can think of. Have any of you experienced the same issue and if so, what was the fix? Any help would be greatly appreciated.

 

[robertray]

I know its a PITA, but I would`nt hesitate to send it in. At least you`d know it would be fixed correctly. You would only be out shipping cost.

 

[Monsta-Tone]

It sounds like something in the power supply filter caps or resistors. The transformer would probably just not work or blow the fuse quickly.

Send it in! Or....find a good Mesa tech near you.

 

[G.I.G.]

It sounds like something in the power supply filter caps or resistors.

This might very well be the case.

I did make another observation after playing around with my Mark V a little more over the last couple of weeks. I noticed that I am only experiencing the issue with it slow to power up when it hasn't been used for a while. I'm not in a band anymore so I haven't been using my Mark V at home as much as I used to. I'm wondering if the capacitors are slowly draining when it's not in use, causing it to power up slowly after sitting for several weeks at a time. Have any of you noticed something similar? If this is considered normal, I can certainly live with it. If its not, then I will probably still send it in or take it to a tech.

 

[Monsta-Tone]

If you are using the Standby switch properly (turn power on 1st, wait about a minute or so, then turn the Standby on), and the amp is slow to power up, then it needs a little bit of help.

Could be as easy as a cold solder joint or bad cap. If it's working at all, it's most likely not the transformer or anything else that is major.

 

[G.I.G.]

If you are using the Standby switch properly (turn power on 1st, wait about a minute or so, then turn the Standby on), and the amp is slow to power up, then it needs a little bit of help.

Could be as easy as a cold solder joint or bad cap. If it's working at all, it's most likely not the transformer or anything else that is major.

Yes, I am turning the power switch on first, letting it warm up, then turning it on.

I think you are probably right and it probably justifies a trip to a tech and/or Mesa for an evaluation. I also called the Mesa/Boogie Hollywood store last week and they haven't hear of this kind of problem either. I'll have someone who knows what they're doing pop the hood and give it a look. I'll keep everyone posted on what it ends up being.

 

[G.I.G.]

I wanted to update this post just in case someone runs into the same issue.

I sent me Mark V back to Mesa a few weeks ago and just got a call with an update. Turns out I had a leaky capacitor in the low-voltage section of my amp, causing it to power up slowly. It doesn't sound like this comes up very often but if you do run into an issue with the amp slowly powering up, it could be a bad capacitor.

 

[jb's 52]

Thanks for the update!