Mesa fifty fifty heater resistors toasted

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clemford
Bottle Rocket
Posts: 10
Joined: Tue Aug 17, 2010 11:22 pm

Mesa fifty fifty heater resistors toasted

Post by clemford » Sat Nov 07, 2015 9:39 pm

hello, I recently bought a 50/50 and opened it up to check under the hood and the two heater resistors 101/102 are cooked badly. I removed the power tubes. I never tried it but the seller claimed it worked ok. Hopefully he's ok. This one has the carbon comp resistors which are pricey and hard to find compared to metal film. There's limited gut shots online but some newer ones I've seen show missing resistors in the 101/102 position. Were they moved? I'm trying to see if the newer ones had metal film resistors instead. They might be tougher than carbon comp and I wouldn't think tone should be a factor in the heater circuit. Not sure if upping them to 5 watt would be overkill. Mine has the deep mod but I'm not sure if it was factory done. The trace was cut next to the heater resistors and the yellow wire was soldered directly to a resistor. Not sure of the number. Seems like the newer version boards have revs. thanks for any help.
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crane
Mark III
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Re: Mesa fifty fifty heater resistors toasted

Post by crane » Mon Nov 09, 2015 3:22 am

Looks like the yellow wire is just resoldered further to the same track.
About the resistors, you can replace them with 100ohm 2W 5% metal film, they are just there for heather-to-ground reference.
PRS McCarty Soapbar with BKP Pigs90, PRS custom 22 with BKP Rebel Yell
Mark V Head, 1x12" Mesa 1/2 closed (EVM-12L)
Triaxis 2.0 noFat - Quad preamp
Deep modded 20:20 - Bias modded 50/50 - SimulClass 295
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clemford
Bottle Rocket
Posts: 10
Joined: Tue Aug 17, 2010 11:22 pm

Re: Mesa fifty fifty heater resistors toasted

Post by clemford » Mon Nov 09, 2015 6:13 pm

crane wrote:Looks like the yellow wire is just resoldered further to the same track.
About the resistors, you can replace them with 100ohm 2W 5% metal film, they are just there for heather-to-ground reference.
Thanks crane.

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