BlueParfait
Well-known member
Checked connectivity on those and they seemed fine. Will check again tho
CrystalSky
Well-known member
Happy NAD!
That’s a lot of knobs
That’s a lot of knobs
BlueParfait
Well-known member
jabps
Well-known member
Lol, again it it wasn't popular Marshall still wouldn't be selling it nearly two decades later.
Check the FS3 and FS4 fuse. You'll need to measure them as they may look fine but can be bad, plus they can cause issue's elsewhere. Marshall fixed this after the first run of JVM's. Hope you get yours fixed. I've never had any problems with either of mine.
BlueParfait
Well-known member
Rocker68
Active member
Power down , remove AC from amp .
Make sure you check fuses removed from their holder . Probe both directions for continuity from fuse holder . You might find the divot .
Assuming your comfortable with this . If not , yeah , tech .
BlueParfait
Well-known member
jabps
Well-known member
Check FS6 as well. And about as tech as I can get is biasing an amp with my bias master lol.
Btw/tons of info out there on the heater fuse issue for that first run in '07. It was something like any amp made pre week 25 could have the heater fuse issue - don't quote me but something like that I read.
My first JVM, the main one that's seen years of live gigs, rehearsals, recording, travel etc... is an '07 as well. I don't know what week, I never looked as I figured if it blows I'll know lol. My other is a 2013 year model.
Rocker68
Active member
What jabps said .
BlueParfait
Well-known member
Never mind. You're all right
It IS one of these fuckers.
So do I find a replacement, or do I just hardwire the fuse holders together?
Attachments
Rocker68
Active member
Very cool . Replace the fuse . You still must address the charred connection . Easy to do . Wire the holders ? I'm not familiar with that work around . I've seen it . Ask Jabps . Make sure you get the 5 x 20 mm length fuses . Sorry if I'm telling you what you already know .
BlueParfait
Well-known member
Nah that's fine, no worries.
I'll go get some 10A 5x20mm tomorrow. I've been thinking about it. Marshall may have recommended hardwiring the heater connections without the fuse, but that still IS an extra layer of protection.
simonfrewler
Well-known member
There are lots of resources available for this issue, and lots of documentation spanning many different forums.
I also think i remember reading somewhere that this problem required a replacement board, due to faulty Production. Something about the traces shorting out between the laminations.
TBH, I wanted to bring this up when you first posted this NAD and said it was a 2007. I just didn't want to rain on your parade, so to speak.
I am sure with some time spent researching this, you will find the appropriate solution....it is gonna be a bit of a rabbit hole. Once fixed though, you will have an amazing amp and a deeper understanding of it ...so there is that.
Don't lose hope!!!
I also think i remember reading somewhere that this problem required a replacement board, due to faulty Production. Something about the traces shorting out between the laminations.
TBH, I wanted to bring this up when you first posted this NAD and said it was a 2007. I just didn't want to rain on your parade, so to speak.
I am sure with some time spent researching this, you will find the appropriate solution....it is gonna be a bit of a rabbit hole. Once fixed though, you will have an amazing amp and a deeper understanding of it ...so there is that.
Don't lose hope!!!
Rocker68
Active member
Review post # 20 . Maybe it doesn't apply
to your amp .
to your amp .
BlueParfait
Well-known member
Thab
A PCB replacement sounds like hell so I guess I'll keep a handful of fuses around. Better dead fuses than burnt boards I guess
ThanksThere are lots of resources available for this issue, and lots of documentation spanning many different forums.
I also think i remember reading somewhere that this problem required a replacement board, due to faulty Production. Something about the traces shorting out between the laminations.
TBH, I wanted to bring this up when you first posted this NAD and said it was a 2007. I just didn't want to rain on your parade, so to speak.
I am sure with some time spent researching this, you will find the appropriate solution....it is gonna be a bit of a rabbit hole. Once fixed though, you will have an amazing amp and a deeper understanding of it ...so there is that.
Don't lose hope!!!
A PCB replacement sounds like hell so I guess I'll keep a handful of fuses around. Better dead fuses than burnt boards I guess
Rocker68
Active member
Your amp indicates 21st week of
2007 ,,,, so ,,,,, your on that bus .
2007 ,,,, so ,,,,, your on that bus .
BlueParfait
Well-known member
Yeah if it becomes a persistent issue, I'll have a tech do that mod
jabps
Well-known member
Yes I think the post models all were hard wired. But as you said, it is a layer of protection and frankly why I've never bothered with my '07. Btw/ does your's still have the original SED Winged C's?
BlueParfait
Well-known member
Still has Marshall branded tubes but I never looked at them in detail
Anyways I'm on my way home and will check, along with installing fresh fuses.
Talked to my usual tech and at some point we might actually just overhaul the heater circuit to point-to-point instead since the fuse holders actually could also burn the PCB
jabps
Well-known member
Yep, original run had the real deal SED Winged "C's", a really great tube. And Chinese 12's.
I did load one of my backup JVM's with KT77's years ago and it sounded good. A little more low end etc...