matttornado
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I realize this post might not be for everyone, especially for those who are vintage purists. I might get a lot of criticism for this but it’s my amp! haha
There hasn’t much about anything that pertains to the old circuit boards Marshall started using back in late 73 or early 74 so I thought I would share this. In case anyone might be interested.
First, I must give a quick history of this amp. It’s a 1974 MKII Superlead that came stock with 6550 tubes, 4 speaker jacks & a polarity switch. I bought it back around 1992. It was in rough shape but for 600 bucks, I snagged it. Right after I purchased it, I gave it to my friend who is an E.E., Amp tech / Marshall expert. He converted it to use EL-34s and gave it a check-up and got ready for me to use. Around 2001, He replaced the Power Tranny because it took a dump. This amp been my main amp all the way up until I started using my DSL in 2018 so it has been worked HARD for many years, mostly cranked through a Marshall Powerbreak for home use, band rehearsals & gigs.
Back around 2008 maybe? I discovered the Metroamp forum & around that time, my amp tech friend started to go on tour with his band, so I started to do maintenance on my own. I also went down the EVH amp mod rabbit hole. That being said, I tried everything swapping out resistors, caps, tried all types of master volumes, etc. Over time, my circuit board took a beating here and there as you could imagine.
Also, this is the same amp I posted on another thread that has the boomy bass I can’t seem to get rid of.
So, While I had covid and was stuck home for two weeks, I decided to remove the circuit board completely and see what was going on underneath as I suspected it wouldn’t be too pretty. Lots of dirt, gunk, flux, dusty stuff & questionable solder joints. I noticed a few solder pads were gone and some components were soldered where they normally wouldn’t go to bypass the non-existing solder pads. Remember that someone had this at least 18 years before me!
So, I’d like to share some of the repairs I did, and how I did them. I tried to keep the underside of the board as original as possible, but I did replace some old components for reliability purposes & piece of mind. Spending $$$$ for original mustard caps were not in my budget so I used what I already had- a few Orange Drops, Mallaory and Bianchi caps. All good for me. I used a small piece of buss wire with a small loop on one end to repair the missing solder pads.
I used green UV solder mask to protect the traces where I did repairs and where the original mask came off or deteriorated. Turned out pretty cool!
I also cleaned all of the pots and put a new ground bus wire on as well. I’ll post more pics as the amp get done and share my final specs. If anyone cares. LOL
There hasn’t much about anything that pertains to the old circuit boards Marshall started using back in late 73 or early 74 so I thought I would share this. In case anyone might be interested.
First, I must give a quick history of this amp. It’s a 1974 MKII Superlead that came stock with 6550 tubes, 4 speaker jacks & a polarity switch. I bought it back around 1992. It was in rough shape but for 600 bucks, I snagged it. Right after I purchased it, I gave it to my friend who is an E.E., Amp tech / Marshall expert. He converted it to use EL-34s and gave it a check-up and got ready for me to use. Around 2001, He replaced the Power Tranny because it took a dump. This amp been my main amp all the way up until I started using my DSL in 2018 so it has been worked HARD for many years, mostly cranked through a Marshall Powerbreak for home use, band rehearsals & gigs.
Back around 2008 maybe? I discovered the Metroamp forum & around that time, my amp tech friend started to go on tour with his band, so I started to do maintenance on my own. I also went down the EVH amp mod rabbit hole. That being said, I tried everything swapping out resistors, caps, tried all types of master volumes, etc. Over time, my circuit board took a beating here and there as you could imagine.
Also, this is the same amp I posted on another thread that has the boomy bass I can’t seem to get rid of.
So, While I had covid and was stuck home for two weeks, I decided to remove the circuit board completely and see what was going on underneath as I suspected it wouldn’t be too pretty. Lots of dirt, gunk, flux, dusty stuff & questionable solder joints. I noticed a few solder pads were gone and some components were soldered where they normally wouldn’t go to bypass the non-existing solder pads. Remember that someone had this at least 18 years before me!
So, I’d like to share some of the repairs I did, and how I did them. I tried to keep the underside of the board as original as possible, but I did replace some old components for reliability purposes & piece of mind. Spending $$$$ for original mustard caps were not in my budget so I used what I already had- a few Orange Drops, Mallaory and Bianchi caps. All good for me. I used a small piece of buss wire with a small loop on one end to repair the missing solder pads.
I used green UV solder mask to protect the traces where I did repairs and where the original mask came off or deteriorated. Turned out pretty cool!
I also cleaned all of the pots and put a new ground bus wire on as well. I’ll post more pics as the amp get done and share my final specs. If anyone cares. LOL