Single Rectifier Solo Head V2--Burned Resistors

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moshpit903
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Posts: 7
Joined: Sat Dec 01, 2018 2:39 pm

Single Rectifier Solo Head V2--Burned Resistors

Post by moshpit903 » Fri Dec 07, 2018 8:41 pm

Image1 hour ago I actually clicked on the clean channel and had about zero volume,even with the channels master volume and gain on as high as it can go,and turned the output control up high as well and then barely got any volume,so I powered down fully,unplugged the reverb pedal from the FX loop,and the TS-9 from the front end and fired amp up again and it was the same but had a really light sound, like when you push the accelerator pedal down and then remove your foot and let the engines revs drop..so once powered off I got my chopsticks ready to tap for microphonic tubes,I started at V5/PI and went down to V1 where I have my Tungsol 12ax7 at and it was definitely the one causing the problem,so I swappped it out and fired the amp up and still the same.

Now channel 2 high gain channel has lost some grind as well,but it was fine 2 days ago and hasn't lost any volume yet.

I got this amp 2 weeks ago today and once I unboxed it I took the chassis out I did a thorough visual inspection of all components and noticed what looked like some work had been done by V1,looking at the underside of the chassis,now say with the rear panel facing me to the far right is V1 ,and there are 3 resistors between 2 large orange capacitors to the left and 2 medium height black capacitors right at the corner of the pcb.

I did download and print out the schematic and I must say that this pcb is nothing like I have seen before,as in I don't see the #'s or locations on the pcb except under the item(s) that get removed,and also on the schematic not your typical schematic imo..but I can see where its damaged so I guess I will have to take out the large pcb and go from there.?

If any of you Mesa Boogie experts read this and have any tips about these schematics,or any of what I am about to do here,as in maybe resistor values etc please chime in.

I am hoping that once I remove probably all 3 resistors that underneath on the pcb that I will be able to see what the resistor values are and hope that the boards not cooked too bad,I think I can save it because the amp still wasn't sounding so so bad on channel 2,but it was working on it.

I am no expert but I trust my abilities to be able to do the work correctly as long as I can get the proper resistor(s) values and types..I have done mods on my ex-Jet City Custom 22,and their pcb's and soldering pads are tiny and fairly light duty,really easy to melt the solder pads,and I have done repairs on my ex Peavey XXX head,as in replacing the channel switching relay,the 2 FX loop input jacks and the 2 control pots,and replacing the 500k SGR's/screen grid resistors to 1K for the 4 power tubes,so I have done some work on pcb boards,but this repair I have to do on this Recto 50 has a lot to be removed to get the pcb out of the chassis,but I am somewhat prepared so I have to get to work on it now.

One more thing,on the pcb is written in white 2000 mesa//boogie,above that raised into the pcb it has REC 50 S2B 1..Also it has the Scrapple from the Apple in the white lettering.

Ok please remember if anybody here has worked on their Recto 50 V2's main pcb in the same area as I am describing,and has any idea what the resistor values and types might be please let me know here or by PM.
Sorry to have blabbed so long !!

Thank you The Boogie Board and its members !

moshpit903
Bottle Rocket
Posts: 7
Joined: Sat Dec 01, 2018 2:39 pm

Re: Single Rectifier Solo Head V2--Burned Resistors

Post by moshpit903 » Sat Dec 08, 2018 8:49 pm

ImageOk I took the main pcb out as much as needed to be able to flip it over to inspect area around V1 on the side where the power tubes fit into the socket(s) and luckily minimal scarring/burned..probably will be ok with it,just need 3 new resistors..

I am going to try to load a picture here of the area at V1 where the actual resistor is fried,you will be able to see the fried resistor.

Now if anybody knows what the value is in ohms and watts of the main burned resistor please let me know what it is,I will replace the resistor on both opposite sides closest to the burned one just to be sure I have fixed the problem..underneath where the charred fried resistor is I can't see any value there,thinking it got cooked as well.

ImageI did some searching on Google and found the exact same problem I have and was said the M-Boogie puts the resistors down so close to the pcb and the traces that carbon forms and cooks parts out,and when I install the new resistors in mine to make sure I have the resistor body at least 3/16' up off the pcb so this problem doesn't happen again,sp I will try that.

The pcb looked like it was really cooked bad but cleaning it up with 91% isopropyl alcohol and q-tips its cleaned up nicely.

I guess if nobody here has any info I will call M-Boogie Monday morning and ask them.

moshpit903
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Posts: 7
Joined: Sat Dec 01, 2018 2:39 pm

Re: Single Rectifier Solo Head V2--Burned Resistors

Post by moshpit903 » Mon Dec 10, 2018 8:51 pm

Mesa Boogie told me today over the telephone that they don't have any pcb's for the Single Recto Solo V2 's anymore,and no boards for any variety of Single Recto,Single Recto Rectoverbs or Single Recto Tremoverbs,so if they can't get me the correct resistor value for where my 1 resistor burned right below V1 tube socket I guess its history..My First experience with Mesa Boogie could be over before it ever really got started..what a drag ! Think about you other owners,this could happen to you and your amp,and if it does you will end up like me and my amp.

I will ask this that if anybody here ever takes their Single Rectifier Solo Head V2's chassis out I would greatly appreciate if you could look on the PCB right under V1 where the 4 resistors are and please tell me here what the 5 color bands are on the 3rd resistor from the left.. these resistors are to the left of which look like 3 capacitors of some kind,2 the same height and 1 taller.

I have downloaded the schematic and don't understand Mesa's schematic at all,its definitely different than all the other ones I have seen and used to do work on amps,so if anybody here knows how to break them down I would appreciate somebody to look on the V1 position and see what resistor is next to the 100k...22k,and in between these 2 and the final 4th resistor at 39k.

The resistor values are written on the PCB underneath these resistors,and mine burned just enough to destroy it where the value can't be seen..my luck.

I have the other 3 resistors values already and they are from left to right..

1) 100K 2) 22K 3) What I need 4) 39k

I would be willing to pay you for your time and effort.

I am not here to diss Mesa Boogie amps,its obvious they have a good product or they would be out of business...I just have sh!t luck,and I know I'm a newbie here and asking a lot but i would do it for you if needed. as always any info greatly appreciated !

Shemham
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Posts: 135
Joined: Sun Sep 30, 2012 4:40 pm
Location: Finland

Re: Single Rectifier Solo Head V2--Burned Resistors

Post by Shemham » Sat Dec 15, 2018 4:22 pm

I don't have Single Rec, but had this stored on my hard drive and it seems to fit your description pretty much. Hope it's what you're looking for.

Image

moshpit903
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Posts: 7
Joined: Sat Dec 01, 2018 2:39 pm

Re: Single Rectifier Solo Head V2--Burned Resistors

Post by moshpit903 » Tue Dec 25, 2018 9:02 pm

Shemham wrote:I don't have Single Rec, but had this stored on my hard drive and it seems to fit your description pretty much. Hope it's what you're looking for.

Image
Hi, I just got back here and see this and its close,and I do see the V1 area and the resistors look the same as what I have here -the burned one.
Since I have been here I have scraped,gouged out all the carbon on the pcb,and filled with Circuit Works CW2500 coating,and everything looks good,but I did overlap 1 of the traces so I am taking to a tech next week to finish the job.
I did locate a tech only 50 miles away from me that charges $45 flat rate and does pricing on the type of job too,but after speaking to him looks like I will pay from $100-$150 max to fix it all up,so I am ok with that !
I have done some research on this tech and also remember a guy i sold a chorus pedal to that lives close to where I live now that recomended him and the tech checks out great..all rave reviews so I am happy that soon it will be finished properly and back to jamming on it !
Thanks for the picture !

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