JVM205H slow startup

[Campbell254]

Hi guys, I’m new the forum and had a question that hopefully someone can answer or at least steer me in the right direction.

I recently purchased a used JVM205H on reverb. I drove out of state to pick it up and test drive it. The guy had it on and warmed up for me so I didn’t catch one odd thing: there is a huge latency between the time you flip the power on and the amp actually engaged (LED lamp on power switch plus the LEDs on the different channel buttons). On a cold start (the amp not being powered for at least a day) it will take as long as 7-8 seconds before anything happens. I noticed once warmed up, (on/off/then right back on) the latency isn’t so terrible, maybe 2-3 seconds.

Any ideas what may cause this? Tone and volume-wise I don’t have any complaints. Functionality seems to be working as expected on all channel. I’ve read that some folks with similar issues simply swapped the LED power switch but mine isn’t just a blown light, the entire amp doesn’t show power on the various channels until I get the power ON LED indication. There’s definitely some correlation there. I’ve read that perhaps it’s the power transformer but I’m not very hardware savvy so I’d have no idea what to check. I am capable of soldering a new power switch but I was hoping to get some feedback before doing it. Might end up having the local shop deal with it but they want a minimum $60 bucks just to look at it.

one last comment: i run an EVH 5150 on the same outlet without any issues. I don’t believe its a power source related problem.

FIXED:

turns out the switch was bad! For those wondering, my particular JVM had a solder-less 4-pin switch that was super easy to change. The old switch clearly had seen better days and looked a bit fried on the metal connections. Once swapped, it turned over (LED power indication in the switch and channel LEDs on the buttons) immediately without any lag. I bought the switch for 10 bucks on studio sounds electronics website. Just make sure you get the switch that claims its for the JVM series. Hope this helps someone else!

 

[paul-e-mann]

Hi guys, I’m new the forum and had a question that hopefully someone can answer or at least steer me in the right direction.

I recently purchased a used JVM205H on reverb. I drove out of state to pick it up and test drive it. The guy had it on and warmed up for me so I didn’t catch one odd thing: there is a huge latency between the time you flip the power on and the amp actually engaged (LED lamp on power switch plus the LEDs on the different channel buttons). On a cold start (the amp not being powered for at least a day) it will take as long as 7-8 seconds before anything happens. I noticed once warmed up, (on/off/then right back on) the latency isn’t so terrible, maybe 2-3 seconds.

Any ideas what may cause this? Tone and volume-wise I don’t have any complaints. Functionality seems to be working as expected on all channel. I’ve read that some folks with similar issues simply swapped the LED power switch but mine isn’t just a blown light, the entire amp doesn’t show power on the various channels until I get the power ON LED indication. There’s definitely some correlation there. I’ve read that perhaps it’s the power transformer but I’m not very hardware savvy so I’d have no idea what to check. I am capable of soldering a new power switch but I was hoping to get some feedback before doing it. Might end up having the local shop deal with it but they want a minimum $60 bucks just to look at it.

one last comment: i run an EVH 5150 on the same outlet without any issues. I don’t believe its a power source related problem.

This is normal tubes gotta warm up before you get any sound. From the time I flip my amp on, plug in my guitar, tune up, its at least 30-60 seconds before I flip the standby off.

 

[Campbell254]

This is normal tubes gotta warm up before you get any sound. From the time I flip my amp on, plug in my guitar, tune up, its at least 30-60 seconds before I flip the standby off.

I appreciate the feedback! I’m familiar with sound requiring some time before becoming available. However, this is less about sound and more about engaging the amp to be turned on and taking a significant amount of time before the amp shows any sign of being powered up. I always leave the standby switch on between startup/power downs so I can’t really speak to the sound on this amp, but I’ve accidentally done this on my other amps and have heard what you described.

 

[paul-e-mann]

I appreciate the feedback! I’m familiar with sound requiring some time before becoming available. However, this is less about sound and more about engaging the amp to be turned on and taking a significant amount of time before the amp shows any sign of being powered up. I always leave the standby switch on between startup/power downs so I can’t really speak to the sound on this amp, but I’ve accidentally done this on my other amps and have heard what you described.

How old is the amp, maybe it needs new power tubes. If youre not confident the amp is operating right I suggest take it to a tech to look it over.

 

[Campbell254]

How old is the amp, maybe it needs new power tubes. If youre not confident the amp is operating right I suggest take it to a tech to look it over.

Good question. I believe the amp to be at least 10 years old or more. I should pull the serial number and get the official age. It’s probably wise to let a tech have a go at it.

 

[paul-e-mann]

Good question. I believe the amp to be at least 10 years old or more. I should pull the serial number and get the official age. It’s probably wise to let a tech have a go at it.

I think its a good idea, good luck with it and welcome to the forum, let us know how you make out.

 

[Campbell254]

I think its a good idea, good luck with it and welcome to the forum, let us know how you make out.

Thanks man! Will do.

 

[paul-e-mann]

Thanks man! Will do.

Check on this thread tonight and see if anybody else has any other ideas, I think youre on the right track though. Cheers!

 

[JTee]

Hey, I just want to thank Campbell254 for posting this here. My JVM 205H had the same problem. I've had my amp since the JVM 2 series first came out in 2008...in fact, I think I got one of the first ones...I ordered it shortly after they announced them at NAMM that year. I still love the amp 13 years later and have no thoughts of replacing it. But a few weeks ago I noticed it started taking several seconds from switching on the power until you'd hear the relays engage and the lights come on. My first thought was maybe it was the relays. It's kind of hard to do an internet search for this kind of problem, but I finally found this post and it was exactly my problem!

I had earlier found a post on an electronics forum where a repair guy kind of addresses this...mentions he's seen a lot of Marshall rocker switches go bad. So these two posts together confirmed it. And what's even better is you said where you got the replacement switch. So I ordered one earlier this week, it came last night and I swapped it out and the amp works perfectly now!

The swap itself was really quite easy...the hardest part was removing the old switch from the chassis...it fits in there really tight. Actually peeled up the gold foil on the face just bit...I pushed it back down, but you can still kind of tell something happened there. Anyway, that's a small price to pay.

I've built two of my own tube amps and actually done a few small mods to my JVM, so I'm comfortable working on them myself, but I am no electronics expert...I can read a schematic and understand the basics, but other than that really just know enough to be dangerous! Troubleshooting problems like this is not my forte! Anyway, this was a great help and I just wanted to say thanks! And I'm guessing there will be others out there with the same problem, so hopefully they will be able to find this.

 

[Campbell254]

Hey, I just want to thank Campbell254 for posting this here. My JVM 205H had the same problem. I've had my amp since the JVM 2 series first came out in 2008...in fact, I think I got one of the first ones...I ordered it shortly after they announced them at NAMM that year. I still love the amp 13 years later and have no thoughts of replacing it. But a few weeks ago I noticed it started taking several seconds from switching on the power until you'd hear the relays engage and the lights come on. My first thought was maybe it was the relays. It's kind of hard to do an internet search for this kind of problem, but I finally found this post and it was exactly my problem!

I had earlier found a post on an electronics forum where a repair guy kind of addresses this...mentions he's seen a lot of Marshall rocker switches go bad. So these two posts together confirmed it. And what's even better is you said where you got the replacement switch. So I ordered one earlier this week, it came last night and I swapped it out and the amp works perfectly now!

The swap itself was really quite easy...the hardest part was removing the old switch from the chassis...it fits in there really tight. Actually peeled up the gold foil on the face just bit...I pushed it back down, but you can still kind of tell something happened there. Anyway, that's a small price to pay.

I've built two of my own tube amps and actually done a few small mods to my JVM, so I'm comfortable working on them myself, but I am no electronics expert...I can read a schematic and understand the basics, but other than that really just know enough to be dangerous! Troubleshooting problems like this is not my forte! Anyway, this was a great help and I just wanted to say thanks! And I'm guessing there will be others out there with the same problem, so hopefully they will be able to find this.

hey man I’m glad my post helped you! It was so difficult conveying to people what was going on with this issue. I ended up bending some of the metal on the chassis too. I’m not sure why it was so hard to remove. I’m almost positive the guy who sold me the amp wanted to get rid of it thinking it was a more serious problem. Again, super thrilled someone gained something from my post!!

 

[JTee]

Yeah, the switch really does fit tight into the chassis...and it being a "snap fit" makes it convenient for installing, but not so much for removing. But in the end, not that big of a deal.

You are probably right about the guy selling you the amp...he might be a bit bummed if he found out how simple the fix was! But it worked out great for you!

Thanks again, hopefully other people with this issue will find this post, too!

 

[William Desilva]

Hi guys, I’m new the forum and had a question that hopefully someone can answer or at least steer me in the right direction.

I recently purchased a used JVM205H on reverb. I drove out of state to pick it up and test drive it. The guy had it on and warmed up for me so I didn’t catch one odd thing: there is a huge latency between the time you flip the power on and the amp actually engaged (LED lamp on power switch plus the LEDs on the different channel buttons). On a cold start (the amp not being powered for at least a day) it will take as long as 7-8 seconds before anything happens. I noticed once warmed up, (on/off/then right back on) the latency isn’t so terrible, maybe 2-3 seconds.

Any ideas what may cause this? Tone and volume-wise I don’t have any complaints. Functionality seems to be working as expected on all channel. I’ve read that some folks with similar issues simply swapped the LED power switch but mine isn’t just a blown light, the entire amp doesn’t show power on the various channels until I get the power ON LED indication. There’s definitely some correlation there. I’ve read that perhaps it’s the power transformer but I’m not very hardware savvy so I’d have no idea what to check. I am capable of soldering a new power switch but I was hoping to get some feedback before doing it. Might end up having the local shop deal with it but they want a minimum $60 bucks just to look at it.

one last comment: i run an EVH 5150 on the same outlet without any issues. I don’t believe its a power source related problem.

FIXED:

turns out the switch was bad! For those wondering, my particular JVM had a solder-less 4-pin switch that was super easy to change. The old switch clearly had seen better days and looked a bit fried on the metal connections. Once swapped, it turned over (LED power indication in the switch and channel LEDs on the buttons) immediately without any lag. I bought the switch for 10 bucks on studio sounds electronics website. Just make sure you get the switch that claims its for the JVM series. Hope this helps someone else!

Sweet.. I'm so glad I looked this up.. my jvm started doing this after not being used for a while.. I don't remember if it had this issue b4 I retired it for a while .. like u said . Once it's been started it powers right up but every time I go a day without playing it usually takes 3 to 5 seconds to light up and the relays to kick in.. just ordered the part.. thx for this post it was very helpful

 

[William Desilva]

Hi guys, I’m new the forum and had a question that hopefully someone can answer or at least steer me in the right direction.

I recently purchased a used JVM205H on reverb. I drove out of state to pick it up and test drive it. The guy had it on and warmed up for me so I didn’t catch one odd thing: there is a huge latency between the time you flip the power on and the amp actually engaged (LED lamp on power switch plus the LEDs on the different channel buttons). On a cold start (the amp not being powered for at least a day) it will take as long as 7-8 seconds before anything happens. I noticed once warmed up, (on/off/then right back on) the latency isn’t so terrible, maybe 2-3 seconds.

Any ideas what may cause this? Tone and volume-wise I don’t have any complaints. Functionality seems to be working as expected on all channel. I’ve read that some folks with similar issues simply swapped the LED power switch but mine isn’t just a blown light, the entire amp doesn’t show power on the various channels until I get the power ON LED indication. There’s definitely some correlation there. I’ve read that perhaps it’s the power transformer but I’m not very hardware savvy so I’d have no idea what to check. I am capable of soldering a new power switch but I was hoping to get some feedback before doing it. Might end up having the local shop deal with it but they want a minimum $60 bucks just to look at it.

one last comment: i run an EVH 5150 on the same outlet without any issues. I don’t believe its a power source related problem.

FIXED:

turns out the switch was bad! For those wondering, my particular JVM had a solder-less 4-pin switch that was super easy to change. The old switch clearly had seen better days and looked a bit fried on the metal connections. Once swapped, it turned over (LED power indication in the switch and channel LEDs on the buttons) immediately without any lag. I bought the switch for 10 bucks on studio sounds electronics website. Just make sure you get the switch that claims its for the JVM series. Hope this helps someone else!

Not sure if I replied to the right comment but I'm gonna try again.. so basically my jvm was doing the same thing.. just ordered the part.. thx for posting this.. it was very helpful