Redplating problem

Pre Recto days. Boogie modified Fenders, Mark I-IV, Dual Calibers, etc

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JMMP
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Joined: Wed Dec 22, 2010 2:57 pm

Re: Redplating problem

Post by JMMP » Mon May 29, 2017 6:32 pm

stokes wrote:Did somebody alter things in there before you got it?
Not to my knowledge, and it doesn't appear as if anything has been altered. Honestly, I was thinking that Boogie's schematic was wrong. I've read several times that their schemes aren't always the most accurate.
Roadster, Mark IV, Electra-Dyne, Fillmore, Traditional/ Stiletto 412
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stokes
Single Recto
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Re: Redplating problem

Post by stokes » Mon May 29, 2017 6:58 pm

Its been a while since I've been in a MKiv,but when I was I dont recall any mistakes in that schem.Most of the iv's I've worked on were cap jobs but a few I did adjustable bias mods and one had a blown 6L6 that took out that screen resistor.I would still replace those 470 ohm screen resistors and see where you are at after that.

JMMP
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Re: Redplating problem

Post by JMMP » Thu Jun 22, 2017 9:53 pm

Another update: replaced the two open resistors and the mark IV sounds better than when I got it! No redplating issues so far (I've only played with it 20 minutes at loud house volume), but under similar circumstances the mark IV would redplate before. I also changed out the EL34s for a new set, so I'm sure that's helping. The new resistors are 5W power handling, but otherwise similar to the ones I pulled out. They are much larger, and will hopefully withstand whatever power made the previous pair open.

Thanks for all of the help! Hopefully that's the last repair she needs for awhile.
Roadster, Mark IV, Electra-Dyne, Fillmore, Traditional/ Stiletto 412
Gone: Quad MIDI Pre, TriAxis V1 & V2, Formula Pre, 2:90, 20/20, JP-2C LTD, TA-15

Henz
Mark II
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Re: Redplating problem

Post by Henz » Sun Apr 21, 2019 12:45 pm

Greetings. I know this is an old thread and was interesting. So which ones were open? The bias in (E) 220k's , or the 220k's , or I think you said they were 150k's going to pin 5 of outer sockets? Thanks, Jim
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