Mark III Fan

Mark I's, II's, III's and the almight IV

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UpNorthMark
Donating Member
Posts: 51
Joined: Tue Mar 07, 2017 12:05 pm
Location: Northern Michigan

Mark III Fan

Post by UpNorthMark » Fri Jan 12, 2018 3:14 pm

Hey guys I just picked up a Mark III Blue stripe head I am totally digging. It’s got a noisy fan and wondered if anyone had a suggestion for a place with s suitable replacement? Your help is appreciated

Mark
Current Amps:
Mark II C+ DG
JP-2C
Mark V:25
& Lots of Cabs!!!!! (all Boogie)

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jediguitarist
Mark II
Posts: 126
Joined: Fri Nov 16, 2012 4:55 pm
Location: East Coast, New Jersey

Re: Mark III Fan

Post by jediguitarist » Thu Jan 18, 2018 12:56 pm

Howard Industries 3-15-2470 is the original from what I can remember.

Globe Motors a47-b15a-15t1 is in the newer Marks.

I've swapped a noisy Globe Motors in my Mark IV for the Howard Industries which I found on eBay. Direct replacement, no issues. Just be aware of the model number. There are slight variation which seem to denote wattage.

This place sells replacement fans. They usually have a few different choices
http://www.amprepairparts.com/mesaparts.htm#fans

93 97 98 PRS CE24
94 98 G&L Legacy
94 G&L ASAT Special
95 G&L S-500
99 Peavy Wolfgang
11 Gibson LP Studio 60

69 Bandmaster Head
88 Quad Pre
91 & 92 Simul 295
92 DC-5
96 Mark IV Maple/Wicker
98 5150 combo
08 Mark IV Wide

UpNorthMark
Donating Member
Posts: 51
Joined: Tue Mar 07, 2017 12:05 pm
Location: Northern Michigan

Re: Mark III Fan

Post by UpNorthMark » Thu Jan 18, 2018 2:59 pm

Thanks, I appreciate the link
Current Amps:
Mark II C+ DG
JP-2C
Mark V:25
& Lots of Cabs!!!!! (all Boogie)

deskman
Mark I
Posts: 48
Joined: Fri Jan 26, 2007 7:10 pm
Location: JMC Academy, Sydney
Contact:

Re: Mark III Fan

Post by deskman » Sun Jan 28, 2018 7:39 pm

I tried a different fan in my IV and IIC+ and didn't really find any difference in noise levels.

The main thing I found is that the noise is really coming from how it's mounted to the cabinet / chassis.
I ended up putting some rubber washers on the bolts / screws to decouple it and it made a huge difference.

Then my tech rewired the grounding switch on the rear to be a fan on/off switch anyway.

You can run the amp with the fan turned off, it's not going to hurt it. Maybe reduce tube life a little.
'in order to realise our creative visions, it is essential that we develop the craft of our instrument' - john petrucci

darkbluemurder
Mark II
Posts: 104
Joined: Fri Jul 28, 2006 5:58 pm
Location: Europe

Re: Mark III Fan

Post by darkbluemurder » Mon Jan 29, 2018 3:43 am

What noise is exactly buggin' you - the noise of the fan turning or is there a hum that shouldn't be?

If it is the fan turning maybe a tech could lower the voltage to the fan to make it turn slower. Alternatively, if you are not going to crank the amp on a regular basis the fan could be put on a switch so it can be turned off. Can be handy in a studio environment.

Good luck,
Stephan

UpNorthMark
Donating Member
Posts: 51
Joined: Tue Mar 07, 2017 12:05 pm
Location: Northern Michigan

Re: Mark III Fan

Post by UpNorthMark » Mon Jan 29, 2018 8:09 am

The fan was actually hitting the housing and scraping as it went around. I shimmed it up which fixed it up. When it was installed at some point someone over torqued one side distorting the housing. It’s still much louder than the one in my JP-2C but no longer audible when I play at low volume.
Thanks for the help guys,
Mark
Current Amps:
Mark II C+ DG
JP-2C
Mark V:25
& Lots of Cabs!!!!! (all Boogie)

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