Dead Marshall Amp Repair - Part 1 - Circuit Trace Repair and Service

[@montygore1200]

I've been a tech for over 40 years. I think the way you repaired the board was genius.

[@dembydish]

Hey thanks Monty! That's a real compliment. Thank you for your comment.

[@hayabusa1300100]

Found this interesting for sure with traces as I like to mod amps . I have this same 8040 and sometime I’m going to change out the power switch I’ve had for sometime with 6 legs it still works and that’s why I haven’t changed it it’s cosmetic but this amp sounds great with a soul food in the front of it I play EVH , Ratt, Quiet Riot , Ozzy Randy Rhoads years through it all the time and absolutely nails the sound and totally agree with these being underrated for sure it’s all Marshall to my ears thanks for the vid

[@jaimegrant784]

I have the same amp. It was exhibiting the same problems as you described. I was almost ready to scrap it, but thanks to your video, I cleaned the sockets and pots and it is now working like new again.

[@dembydish]

I'm glad you got it fixed! Thank you for your comment and best wishes for a Happy New Year.

[@songman68]

I love the turret fix. I didn't have any turrets sitting around so I did a similar fix recently with some 4-40 screws and kep nuts. I wrapped the components around the screw like turrets and soldered them to the screw.

[@dembydish]

Thank you for your comment.

[@JoeFen]

that copper ribbon stuff is handy for removing solder that doesn't want to get sucked up.

[@AscaAxes]

I have the same amp model no more working. Volume was floating and I had fixed for a short time by resoldering each component. Thanks to your video I've found that power amp is still ok. I'll try to clean out/in sockets to see if I could save also preamp ch.

[@dembydish]

Yes, it's good to clean all sockets well. I stupidly plugged mine (USA 110v) intro a 240v supply and ruined it! I am going to try to repair it and make a video. If you're interested subscribe or check back later. It might have some useful information. Thanks for your comment. PS. I still like this amp, I think it's underrated. However, I don't think it was designed to last a long time.

[@santiagomoreno696]

Nice approach with the turrets.

[@dembydish]

Thank you, I like your channel BTW.

[@andycdgreen]

Hiya, great video! Please could you provide a link to the replacement pot nuts?

[@311superfly]

i have exact same amp. needs pots cleaned . crackles when volume knob turned . what are the odds? lol

[@nigeltrueman5931]

Thanks for the video, always interested in ways to fix dreaded PCB track issues. Any chance of adding purchasing link for those turrets and or specs. as I am having trouble locating the ones you used in the video. FYI. I am searching Mouser here in the USA.

[@LieutenantDan82]

Hey man. I have an MG30FX, but I'm not getting any sounds. The lights turn on but no sound. The capacitors don't look blown. What do you think it is?

[@dembydish]

Start by cleaning all the jack sockets well with an electrical switch cleaner.

[@dynamn]

My MG50DFX clean channel has very low volume, the channel switch is temperamental, do you know where to look at please? thanks in advance.

[@dembydish]

Well, firstly sort out the obvious. Given what you've said, the channel switch, jacks and pots should be cleaned with a proper switch cleaner to see if you can bring the switch etc. back to life. Then check your guitar cables and clean your guitar jack. Then see what happens and re-evaluate.

[@irfuel]

Is the solder you use lead or lead free, on those boards?

[@dembydish]

@@irfuel I used 22 SWG / 0.7mm / 60% tin / 40% lead. It's what I had to hand as I have a large amount left over. Either would do. Thanks for your query. Please subscribe.

[@stevelueb7787]

Super Glue melts with heat. Your soldering iron is well above the melting point of super glue

[@davidstorm4015]

Rather than repairing the trace, would it not have been easier and still very robust to replace the trace and jumper to the destination with a piece of thin wire?

[@dembydish]

I just wanted it to look as neat as possible. Thanks for your comment.

[@michaelmcsky]

USE FLUX, FLUX, FLUX TO DESOLDER PARTS! NO MORE BREAKS! I did the same desoldering mistakes...

[@montygore1200]

No solder wick?

[@robbysguitars8223]

Good sound. Nice Jimmi.

[@MyJeff1969]

My Marshall gfx 30 stopped powering on Where should I start?

[@dembydish]

Start with the fuse and plug wiring, then check if the mains on/off switch is working correctly.

[@MyJeff1969]

@@dembydish my model has fdd No serviceable power cord And from what I have read the fuse is inside the amp So I will have to take it apart

[@MyJeff1969]

@@dembydish yes the power switch could have went bad But I will look for the fuse first I will give you the exact model # when I get back Thanks

[@dembydish]

OK, this video may be useful in how to approach getting to the fuse. The glass fuses are generally available on eBay if that's the issue.

[@MyJeff1969]

@@dembydish I replaced the power switch and fuse still nothing and while pulling board out to inspect it the main vol pot snapped had to piss amp off keep it for parts I bought a Marshall code 25 for $152.00

[@nicolaslorenzocosimi5639]

♥♥♥

[@patprop74]

did you ever figure out why the Tube resistors get so hot?

[@dembydish]

Not yet, unfortunately I plugged it into a 240v supply and did some serious damage! I now have to rebuild it. I might find out at that time. Happy New Year.

[@patprop74]

​@@dembydish so you think it was an amp made for the USA market that runs 120V?

[@dembydish]

@@patprop74 I purchased this amp in the USA when I lived there. Marshall's biggest market is the USA. Back in the UK, I usually plug it into a 110v power transformer, but I forgot to select 110v. So it took 240v, blew the fuse and damaged the main board. All this after servicing it.

[@patprop74]

@@dembydish Dammm, So sorry, Things happen, I'm sure many many amps got blown because of a silly mistake like that, I love those amps, I still have two of them. and an 8080 and an 8020 haha Replaced pretty much all the 1Meg pots on almost of everything Marshall made in the Valvestate line up and the input and output jacks ABSOLUTELY need to be pulled out and properly cleaned with light sandpaper on their contacts, I don't even want to think about how many of these amps got scrapped just because of that problem with sub-par part. do you have problems finding parts for those over there in the UK? things like Pots and the front plastic logo and such?

[@311superfly]

dude you touch the resistor you replaced and it moves and appears to drop!!!!!! clear as day . after ALL that work?

[@bluezsb]

you shouild show how you open the amp.

[@dembydish]

Undo the 4 bolts on the top and the amp section will come free and can be removed.

[@311superfly]

I am only one the see resistor LIFT out of soldered hole when you touch it. 24:16 clear as the sun. sorry