Marshall Lead 100 Mosfet 3210

[gorn]

Hey everyone
Received my new to me Lead 100 Mosfet today.
Externally, it looks great, consider it was made in '86.

I bought it cheap, knowing that it has issues.
PO says severe crackling sound, no guitar sound, unuseable.

Considering a working one would cost me over a grand easy, I figured I'd roll the dice on a repair job.
It cost me 385 Australian peanuts, or about 280 US clams, or almost 200 pommy pounds

NOTE !!!!!
I WILL NOT BE DOING THE REPAIRS.
I don't feel like starting a fire, or electrocuting myself lol.

Here's what it is...
Marshall 3210 Lead 100 Mosfet
13/03/86
Signed off by Caroline

Drake transformer 789-66/6
Mosfets K135 Japan 5B1 and J49 Japan 5H1
Missing C6, C7 and TR8 on main board.

I will be using this thread as an informational type thing, but am more than happy for you guys to jump in too

First off, pics of what I have.
Later on I will post what my tech has to say....providing he will touch it lol.

 

[gorn]

Inside from L to R
It says 120V, but the PO said its wired for 240V Ozzie volts.

 

[Dave J]

Sad to see this fun amp in such disrepair, I hope you can find a tech to get it back into tip top shape. I never owned one but did use one once at a gig. The other band's guitar player had it and let me use it for my bands set. We played hard rock and this amp was a far better choice than the Fender Twin with a very old DOD overdrive 250 I showed up with. Sorry to barge in with no real info, just have fond memories of that gig and this head with the matching 4x10.

 

[Gunner64]

Holy Mackerel..a thousand for a lead 100 mosfet?..

 

[fat_lenny]

Nice, I picked up one last year and love it.

I'd wondered if mine had been played with internally. From yours I am thinking mine has.

- C9, there is nothing in mine
- C6, my photo isn't clear
- C7, like yours mine has nothing there.
- C43, yours has been cut
- TR8, like yours mine has nothing there

I might go through your photos and see what else appears different. That was a quick look. If you need any gut shots of mine, let me know.

I'll have to check what year mine is (its a T serial number), but I wonder if there has been changes through the years the amp was in production? Anyone able to chime in on this?

 

[gorn]

well, update.
So, I didn't bother trying the amp out first, as going by what the PO said, it would be a crackly non event anyway.
So today I cleaned all the pots and input jacks several times. Working the knobs back and forth.
once I was happy with how the fealt, and probably 3 rounds of spraying them as well, I put it all back together.
Plugged everything in, every knob set to zero.
Footswitch, input and output leads plugged in.
Go time.
She turns on, and makes no crackly or static noises....HOORAY!.
Actually, it makes no noise at all, regardless of where anything is set. Footswitch does change channels.
Still nada.
I had checked the fuse before reassembly, and it looked fine.

So this is why buying an amp with known issues is a gamble lol.
It could have just been filthy pots and jacks, maybe a fuse.
Nope. Something beyond my skills is wrong with it.
Now to phone my local tech, and see if he will have a look/test for me.

No wonder Im going grey lol

 

[fat_lenny]

well, update.
So, I didn't bother trying the amp out first, as going by what the PO said, it would be a crackly non event anyway.
So today I cleaned all the pots and input jacks several times. Working the knobs back and forth.
once I was happy with how the fealt, and probably 3 rounds of spraying them as well, I put it all back together.
Plugged everything in, every knob set to zero.
Footswitch, input and output leads plugged in.
Go time.
She turns on, and makes no crackly or static noises....HOORAY!.
Actually, it makes no noise at all, regardless of where anything is set. Footswitch does change channels.
Still nada.
I had checked the fuse before reassembly, and it looked fine.

So this is why buying an amp with known issues is a gamble lol.
It could have just been filthy pots and jacks, maybe a fuse.
Nope. Something beyond my skills is wrong with it.
Now to phone my local tech, and see if he will have a look/test for me.

No wonder Im going grey lol

Good luck with it.

I hope you get it running. For reference, I paid just under $500 AUD (including postage) form mine late last year. I'm still not convinced the insides of mine are all the way they should be out of the factory though.

If you get yours running, its well worth it. Killer amp.

 

[gorn]

thanks mate.
Im looking forward to some tunes from Kill Em All and Ride the Lightning
Hopefully I can get it working asap.

 

[gorn]

well, I took it to the tech today.
It's not the Mosfets. The power amp section is working fine.
Pre-amp...meeeeehhhhh not so much lol.
He emailed me not long after I sent him a schematic for it, and said he had already found some cold solder joints on the board.
Also said I got lucky with the reverb tank too. Mine is the first working one he's ever seen from these models.
Now I guess I try and be patient, while the voices in my head scream NOW NOW NOW NOW NOW.
You get the idea lol

 

[Dave J]

well, I took it to the tech today.
It's not the Mosfets. The power amp section is working fine.
Pre-amp...meeeeehhhhh not so much lol.
He emailed me not long after I sent him a schematic for it, and said he had already found some cold solder joints on the board.
Also said I got lucky with the reverb tank too. Mine is the first working one he's ever seen from these models.
Now I guess I try and be patient, while the voices in my head scream NOW NOW NOW NOW NOW.
You get the idea lol

I hope your tech can get this amp running. I don't think waiting for gear to be fixed or shipped is a guitar players strongest attribute !! NEED... GEAR...NOW !!

 

[gorn]

Nice fast service!
Got the amp back home.
So, he checked every cap and resistor on the board, all within factory spec.
In the last section he was working through, he was finding weird voltage fluctuations, big ones.
Turns out its an op-amp chip had short circuited.
He says he's seen this before when the amp is driven too hard with pedals and the like, boosting the amp.
Not just ordinary, run a distortion pedal or a single overdrive pedal.
But ganging up multiples of them can be hard on these chips.
Anyway, rather than soldering a replacement in, he soldered in an 8 pin female socket, so if it ever happens again, you just pull the chip, and push in a new one.
The issue with these Mosfet amps that is fatal, is if the coating of the main board lifts away due to heat.
I don't know how to explain it better lol.
Basically if that happens, it's not repairable. So yeah. A forward thinking tech, fast, and very good pricing too.
The chip is a bit bigger than a tic-tac
The next step is to make the time to have a play with it.
Im pretty damned happy as is though. I paid $375AU for the amp, and $100AU for the tech.
In Yankee Doodles that's about $347 USD , or $314 EU, or GBP $263

The culprit

 

[Dave J]

Awesome ! You have a great tech there, that is valuable. Can't wait to hear your thoughts once you have had a chance to play it. Glad this turned out to be a better case scenario for you. Another cool amp lives on!!

 

[lespaul339]

Nice looking amp! Congrats! Glad you got it up and running!

 

[mark123]

Holy Mackerel..a thousand for a lead 100 mosfet?..

Yeah, it’s more like $300 for a working unit.

 

[gorn]

Awesome ! You have a great tech there, that is valuable. Can't wait to hear your thoughts once you have had a chance to play it. Glad this turned out to be a better case scenario for you. Another cool amp lives on!!

thank you

Hell, even if I don't like the way it sounds, it should make a kickass pedal platform

 

[gorn]

Yeah, it’s more like $300 for a working unit.

not here it isn't.

I don't know where you got your price from. Maybe pre covid? Or just lucky.
Only 1 on ebay is over a grand https://www.ebay.com/itm/193893761772?hash=item2d24f802ec:g:o9QAAOSwGaRgKmMK
Half stack on Reverb is cheaper, but not $300 cheap https://reverb.com/au/item/34352676-marshall-3210-mosfet-100-1965a-cab-1985-black-brown
Last discussion I saw about value of these, on this forum, OP was asking value of his half stack.
Most agreed that just the head was worth $500 USD in today's climate.
I wish they were $300. That would be awesome lol

 

[gorn]

this is the cheapest I could find https://reverb.com/item/52112955-marshall-model-3210-lead-100-mosfet-head-1980s

 

[fat_lenny]

this is the cheapest I could find https://reverb.com/item/52112955-marshall-model-3210-lead-100-mosfet-head-1980s

I picked up mine for $500 (AUD) last year. Ive not seen many of them for sale lately.

The SS combos over here are all on the rise over the last 18 months.

I think you've done pretty well in our market with what you paid, even after repairs.

 

[gorn]

I picked up mine for $500 (AUD) last year. Ive not seen many of them for sale lately.

The SS combos over here are all on the rise over the last 18 months.

I think you've done pretty well in our market with what you paid, even after repairs.

I thought so too.
It was definitely worth the gamble of buying a non working amp.

 

[gorn]

So I fired her up tonight.
Here's my thoughts on how it sounds.

Clean: I really like it. I don't need pristine clean, just a nice well rounded sound that's not 2D. It does this very well.

Reverb: There isn't much there, but what there is works well. Anything past 3 o'clock though, and it has this slight "ping" noise to it. Like its overdriving or something like that.

Distortion: Without a boost, its OK. Gotta remember I like metal, so a crunch tone doesn't offer much for me (at least at this point in time)
I would expect it to fit perfect for old school rock from the 60's or maybe 70's though.

With a Boss SD1 maxed out, it's better, but getting the eq right is a pain. Its either a bit muddy, or too much treble.

With a Joyo knock off pedal, based on a Tube Screamer, it's better overall, but still not quite there as far as the amount of gain.
Pick attack sounds much better with this pedal, but again, isn't quite saturated enough for me.

Also, I really dislike the pulled setting on the OD volume knob. What an awful muddy sound. I'd never use that, EVER lol.

Mine has the traditional POP when switching it off, as many other owners have reported. Made me jump a bit the first time lol.

Its silent on the clean channel, no hiss at all, until you engage reverb. Then it has quite a bit of SS white noise hiss. Not worth complaining about though.
When the OD channel is on, there is a low buzz, that's about half the level of the reverb being engaged.
OD pedals are a little bit squealy, but I usually use a noise gate anyway, so not an issue.

Please keep in mind, this is the first time I've had a play with it.
I'm sure there are great sounds in there for other music genres. But metal....not quite.
Is she a keeper? Its my first Marshall, what do you think! lol