How to repair fix Troubleshooting solid state Marshall MG series guitar combo amplifier Jacks
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- Опубликовано: 11 янв 2017
- This solid state amp came to D-lab with screwed up front panel jacks. Damage was caused from tripping over cables. I really didn't want to fix it, but the amp landed in the shop and needed love.
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Good to see solid state repair is FINALLY making it to You Tube, I have has three Marshall MG amps go out on me and could find no guides to diagnosing and fixing problems.
Got to say, I really like your humour - you made this both informative and funny.
Solid State Amps especially the past 25 years have become incredible i use to believe Tube Amps were the only way to go that all changed in 2007 when i was ask to play out of a 100 Watt Marshall MG Series Amp it was brand new i said sure..ten minutes thats all it took and i was hooked the Marshall MG Solid State gave me everything tone versatility..i bought that Amp and 12 years later i still have and use it No issues with it not a one it has 12 years of heavy use and i can still count on it all the time..2009 i bought another Marshall MG 100FX 2X12 wiith stock Celestion Speakers..its 10 years old and still reliable as ever no issues in ten years and performs incredibly..you can not say this about any Tube Amp..
Terry,
I only had a chance to exchange a few words in Kalamazoo (2019 VEE), and wish we talked more because your knowledge and work is done with such precision! Excellent videos! - FYI- I was the young guy w/ the Yamaha CR-620, which you mentioned you had gotten for your daughter. I hope we can touch base again soon b/c I'd like your insight on a Dynaco ST-120 (Project in progress; I have a PAT-5 to match it too)
Thanks!
Thanks for that part#. I've got the same job to do on the same darn amp, and I've been putting it off for awhile now.
I've always been impressed by what I can find at Amplified parts (CE Dist).... lots of jacks for these critters.
Awesome video man! Never knew how to take a component of a circuit board until now.
Terry rocks....love these videos
Man, you do such a professional job on these things ! Love it.
Very well done, Terry. Thank you.
Good vid, Thanks Terry.
nice repair terry big thumbs up
Sometimes Electronic Goldmine carries those jacks. I usually check their prices against Mouser and Digikey just in case their idea of surplus pricing is a little off. I love the Hako desoldering tools!
Another great Tech Tip from d-lab
VA6RDR
Thanks
Love your vid's.
I have a manual, Solder sucker that works pretty well.....but lets be honest...the jacks and bench fee woulds have cost more than the amp itself! Anyway, Love your videos D-Lab thank you!
Sure I like and good advice : Thank you SR.
love your channel sir, so much great info! i had one question if you get around to it. i'm trying to diagnose my small Crate bx-15 bass amp...symptoms are: it sounds great when you first strike the note or chord on a guitar,. crisp clean solid tone....and as you let the note susain out, it gradually distorts into a fuzzy crappy tone within a few seconds...any ideas or insight would be appreciated...thanks in advance!
In my shop I would have pulled both of those jacks with just a nice Weller soldering station, copper wick and a flux pen. Five minutes, piece of cake. A decent tech should be able to do that without damage.
Thank you for sharing expérience and knowledge with style :-))
Cheers from old Europe
What temp do you tend to set your iron at for clearing holes with the soldering wick?
Desoldering stations are worth every penny...Wouldn't be without mine. :)
I love my chemtronics solder wick. Sucks up solder like no business and then I can remove the part easily.
Hi Terry! thanks for the videos! One point of confusion. I've seen you mention not to use solder suckers, yet on the first jack you removed, you used a solder sucker. Then even more confusing is when you take out the second one, you didn't use the solder sucker......Thanks again!
Hey man, Glad you liked. The first instrument is not a solder sucker, rather a de-soldering station. A solder sucker is a hand tool with a plunger, a real mess to work with. I prefer a de-soldering station or wick for removing PCB type components. Hope this helps
Did you modify your desoldering station to be used with a compressor or it came equip like this if you did how did you do it most of these desoldering station come with a very weak small fish tank vacuum pump ??
Hi Terry, I have a Marshall valvestate amplifier I unplugged the speaker and put it threw my mixing board 20 years ago, I let a guy work on it but he couldn't fix it, the model is a stereo chorus 8240, do you think you can bring it back to life or is the cost to do so not worth it? Thanks!
dumb question - do you have to discharge caps to work on SS stuff? Getting an old marshall 250 dfx and wanted to know in case i want to take a shot at cleaning it up.
Great video..
great man! you are the best!
Hey Terry I'm new to your channel and are really enjoying it. Where do you buy your F&P caps? I'm restoring a Marshall 5275... 75 reverb..
I'd appreciate your help..
Have you ever caught one of these (or similar) not getting its pot up enough to the last FX (octave) effect? It seems the pot is "biased" and does not get to the desired value to switch that last position on. :(
I have one of these amps. I would like to replace the input jack an foot control jack an headphone cell phone jacks with quality parts made of metal . Can i use input or out put jacks from flanger foot switches or other electronic scrape parts
amazing video!
could you help me identify this same headphones jack but for a Marshall MG102CFX,
I just unsoldered it cause it needs replacement, but it looks a bit different than this one, and I cant seem to find it ;C
Got a question: I have a MG50DFX and my clean channel is dead. Overdrive works, clean does not. Any thoughts?
I have a Marshall G30RCD and want to upgrade the speaker, do you know if I need a 8 or 16ohm speaker ? Thanks in advance, Steve
What’s this problem?
I’m getting a faint “pst” every 60 seconds or so. Amp still works well, but it sounds like something may be failing on circuit.
how do you get the amp out of the cab? im having a lot of trouble
These amps aren't that bad to work on. It's really a matter of what is "familiar" and "unfamiliar" to you. I know a lot of amp techs are "familiar" with tube amps and how they are constructed, therefore, a solid state amp is an "unfamiliar" device. As such, they don't want to work on them.
I know how to work on solid state electronics, so to me that is what is "familiar", and a tube amp is "unfamiliar". I am more comfortable with the solid state. The good thing about that is I can buy broken solid state amps super cheap and fix them quickly and cheaply. Most times it's a matter of a cold or dry solder joint, or a worn out capacitor. Parts are really cheap and I always order more than I need so I can build up an inventory of parts.
Also, learning how to read a schematic is a critical skill. It looks difficult at first, but once you learn how to do it, then you can fix literally anything electronic.
A electronics service technician is judged by how well performance is returned to original performance that is measured specs power THD frequency response that is classic work and what I was taught and the up side is you can fix anything but your stuck with there definition of right but nice repair depends on getting the Right part
Do you have to ground yourself before getting inside one of these amp board ???
Nice!
I got a It's a Marshall MG15HCFX mini stack and it won’t work anymore. What do you think is wrong. Won’t even turn on.
My MG50DFX clean channel has very low volume, the channel switch is temperamental, do you know where to look at please? thanks in advance.
Hi i have a Marshall 5212 solid state. The problem i have with it is then the power of it sounds like a bomb goes of.Do you know whats wrong with it?
Hi. I have a problem with the marshall mg101cfx amplifier. Could you help? Thanks.
How can i fix the fx/reverb board for the mg30cfx or where can i buy a new one?
excellent video .. I'm designing and building a tube amp with ECC83 Tubes as preamps and one for a phase inverter feeding a pair of 6L6GC as push pull to a Output transformer. Your thoughts and comments are welcome!
Is repairing this amps also as dangerous as tube amps?
I want to change a component on my own but have little experience, im not sure what caps i shouls discharge
Please help! Can i deactivate the fx chanel? It is stuck on chorus and delay and it dont turn off...what can i do????!
Terry have you ever work on an at-1 heath kit transmitter. Dewaine
Hi. I have got a marshall mg50cfx amp.But the headphone jack broken.I mailed to marshall and they sent me a message that the part number is '' PCBS-91017.. And one of my friend told me that my amp uses 9 pin stere headphone socket (3.5 mm 1/8 inch ). How can I find this spare part ? Because a technician here couldnt repair it because he said he doesnt have the spare part needed.
Hallo, have you got a schematic or circuit plan for MG50CFX? and if yes. would you send it to me??? greetings Ron.
One question, I plugged my Les paul to a MG15CD and the light turns on but I don't get sound, the guitar and the cable are fine, how can I know if the speaker is broken or other part? Thanks in advance
find a schematic,the proper one ,they have amendments made to amps and some have slight differences,but get the correct schematic the type should be numbered on the pcb,trace the audio circuit,from the input of the TDA2030 monolithic IC power op amp,a 5 pin device with a large finned heat sink attached,the schematic will shown two inputs one + non inverting and one - inverting,plus and minus signs,using an insulated thin screw driver tap the input pin,a clicking noise should be heard,this is called the "click test",using the schematic and capacitor and resistor numbers ie C14 or R22 for example,trace backwards from the power chip to the input,this will show where the signal has not passed and the fault lies here,you can work from input to output also,but out to in will show if the power amp is kaputt or not,test the speaker with a 1.5V AA cell,wired to negative on the speaker tap the positive wire to the AA cell or speaker,which ever way you have the ends connected,don't hold it for long 1.5v should be safe enough , you will hear a scratching noise and the cone will move out if you have + to + and - to - if not the cone will draw backwards,no harm in either way,but it will show the speaker is fine,this is how speakers with no + or - are "phased" to connect two or more together.
google "amplifier click test",someone may even demonstrate it,be aware of live voltage areas,where 110/220 Vac is ,the highest DC voltage is 15Vdc or so as safe as that DC voltage is,if you mistakenly short out the power you may burn out a component leaving the click test redundant,study the signal path,inputs to the op amps and the outputs of the couple of opamps that live in the amp where the outputs go,look for dry solder joints,broken copper traces,use a magnifying glass if you can,you really need to measure the "DC" voltages of the power supply,two zener diodes one makes the -15Vdc and the other makes the +15Vdc,both have one end connected to 0V or ground so this common point can be used to keep one test probe still while moving the other test probe to the other zener diode,they are marked ZD1 or ZD2,normal diodes are just D1,D2 etc,the zeners will be side by side on the pcb in the mid area of the board,i have a couple of these amps right now ,one has a massive thump at turn off or "TRANSIENT",though the power op amp may be faulty,or a power supply cap or a transient suppressor may need to be added,i hear these and other solid state amps do the hard thump at turn off.
I work with tube amps mostly,these little IC amps are quite simple.
Have fun and be safe,do not touch it if you can't do it,if you do touch it the mains AC voltage will or should be to the left side looking at the amp ,behind the rocker power switch and mains input cable.
If you mess up don't blame me,you have been warned and informed.
i replaced jacks on one of the MG series amps,same foot print as myopen type pcb mono 4 pin jack sockets,in fact mine are better than the marshall offerings as mine are easier to clean,being open,not having the melted stud plastic cover,when the jack is dirty it's dirty,cleaning should be easy not fangle mangled.
Sir I have a pot that wont turn ....what do I do to loosen it so it turns again?
Those knobs should be even closer together :)
I exactly have the same amp. The audio drops out when I press the crunch button and the overdrive button.
What would be a cause for a solid state if no sound to speaker. Replaced driver caps and other main caps. But still no sound. Peavey guy said it could be something with dc problem. What do you say. It’s a peavey solo series 112 with scorpion reverb. I turn it on and all it does is make the speaker push out. ??
Have you checked the voice coil on the speaker? I had a Peavey 30 in the shop, same issue, speaker coil had opened.
D-lab Electronics yes. I use the speaker for my Marshall head as a back up. It works fine.
I can't pull my amp out of my MG15 combo, removed all the screws and still won't come out. Could it be glued?
It's not glued, just very tight. I used a flat knife and jammed it into the space between the two pieces and after lots of wiggling the baffle came off. I left mine off because my amp was overheating and breaking down.
Terry,
Would Solder Wick and a 25 watt soldering iron be safe to use, or would it be too much heat for the foil? By the way since you recommended Solder wick, I don't even know where my solder sucker is located. LOL Thanks for the great videos!!
Yes Sir, just use a good fine wick, like Chemtronics
I can repair entire amp with my 25w radio shack iron, chemtronics solder wick and 63/37 or 60/40 kester solder. Add to that $30 mastech 8268 multimeter with three AAA eneloop rechargeable batts and you're in like Flynn.
hi..i am jorge, from rio de janeiro, brazil..i have an old hartke VXL 200 bass amp i bought damaged on ebay..my friend fixed it but not completely..i mean..its presence and edge controls do not work..everything else work fine..i would like to have those two controls working fine but my friend could not find that amp diagrams..so would you have its electric diagrams? or could you find them? if so, would you have a paypal account so i could pay? please, let me know it..thanks. jorge.
I have gotten away with the "squeeze bulb" desoldering iron..
What is the all circuit integrated. Have this amplifier friend
It is... Hold on brb. 6 years later. Hi yaw!
I am helping my friend who lives over seas (Portugal) to find a transformer for his Marshall MG 30CFX amp. He is having no luck over there. I tried Mouser with the part numbers, but nothing coming up. Do you know a place I can find one? Here's what he sent me w/part numbers.
Marshall part numbers;
066-MGUD
VT 1305 120HZ
Standard part number stamped on the power transformer;
S66 X60
HB 8585
Thanks. Appreciated if you can help out.
Philip
Exact thing happened to me with that same amp, thay were cutting in and out and when the cord in the plug was sitting right it worked for wee bit then the quietly of sound and tone would be up and down, I thought maybe I could have a look and try fixn them but ended up making them worse so then thought I might as well pull them out and out of the way so I can carry on playing an replace them later, but yes I damaged the bord wigging them out and now I have all the power lights but no sound what so ever, I've tried to find out exactly what I did to it apart from turning it into a can of worms, is there any easy way of fixing her, i ive away out from town and don't know when I could even get it to a shop for repairs but yeah bla bla bla haha wish I didn't fuck it to start with now it's a good amp but shit design those little plugs
🎪 Circus Board!!!! Yep!
ou need to spring for a wine glass. just a jest.
Is this amp digital?
It runs on a coal and steam engine. There's this lil midget that lives inside and every blue moon youz gotta open the box and feed him... Hi yaw!
thanks walter white
3rd method.
Drop a twin reverb on it and crush it lol
just tubes
No such thing as a good sounding solid state guitar amp.
Not true -- Quilter and more
Pete Dazer roland jc-120, Lab series amps, Polytone amps, early Randall orange and silver panel amps, even newer stuff like Quilter...I could go on. If a solid state amp is designed well it can sound good. It won't be AS good as tube, but it can fool you. A lot of cheap beginner amps and poorly-designed solid state amps are not indicative of what the technology can do.
Acoustic 150 and kustoms too different sound but good !
Marshall makes good sounding solid state amps.
Check out the new Boss Katana - Orange crush Pro - or Roland blues cube amps ! I recommend these over cheap tube amps anytime ! Sunn beta lead and old Marshall Lead amps are very underrated Awesome sounding solid state amps too !
What’s this problem?
I’m getting a faint “pst” every 60 seconds or so. Amp still works well, but it sounds like something may be failing on circuit.