This is a dying art. Glad to see someone sharing years of invaluable electronics knowledge. Great work!
@d-labelectronics
8 жыл бұрын
+MrBillinchar Thank you Sir. I enjoy repairing and sharing
@robertphillips597
5 жыл бұрын
P.s. a million thank you's for making these videos. They are greatly appreciated for those like me who are curious and want to learn how this stuff works and maybe start building some tube guitar amps etc.. late merry Christmas and have a great new year's!!
@rogerdekguitar
7 жыл бұрын
This is a fantastic help; thank you so much! You took my fear away from getting into repair of those wonderful amps. I recently repaired my old 8080 (broken solders exactly at the similar resistors) and it's now back to live again. I am looking for a solution to use a 3fold-footswitch (Marshall PEDL00014) with my Valvestate S80 8240 and try to switch not only between clean/distortion, Chorus on/off, but also OD1/OD2. - I understand that some changes at the wiring of the S80 have to be done, e.g. replacing the input socket of the switch (from 2 to 3 way) and wiring it to the OD1/OD2 internal switch. I think a lot of other Marshall fans out there would love it. Would you give that project a chance? -
@B4its2L8guy
4 жыл бұрын
Just bought a Valvestate s80 for $100 not working. I pulled the PCB and found a failed solder on a capacitor. Soldered it back and the amp came back to life!!
@jasonhilarius6328
6 жыл бұрын
My hat off to you sir... a scholarly gentleman it his best !!!
@BlueberryStinkFinger62
6 жыл бұрын
Fist i want to start by saying glad i found your page..you can really learn from you great job..looking forward to more of your videos..i also want to say i have two Marshall MG series Amps..2006 MG 100HDFX...2009 MG 1OOFX i have had not a single problem with them both..they both are fantastic Amps..i also have two JCM's..the 800 and 900 i have had issues with both especially in the tube department..and power switch with both..i run the MG Marshall's with the JCM'S..sounds fantastic when i do that..but as far as reliability..its the Marshall MG's with out any doubt..i can count on them every time..i can't say that about the JCM's..as far as power and Tone i can't and won't put one over the other..as far as reliability its the MG Marshall's Hands down..
@anthonymarez7188
6 жыл бұрын
thank you for the video, I have a chance to get a vs265 but was kind of on the fence at a good cost from a friend you taking my fear away the amp works fine now but at least I know what to look for in the future thanks again
@Pstaines439
3 жыл бұрын
Loved the video. I’m learning a lot. I just bought a Marshall MOSFET 100 reverb. All 13 pots have been snapped off😳 and there are some weird noises, crackles and bangs when I turn it off. Looking forward to diving in!
@chakakhan3751
3 жыл бұрын
I have an old vs102r hanging around that stopped working. Think I’ll get it repaired. Great vid
@virgyltracey8454
8 жыл бұрын
THAT WAS REALLY USEFULL.THANKS A LOT D LAB....
@cowasakiElectronics
4 жыл бұрын
My brother in law brought that same amp to me for repair. Normally I only do tooobs but as a favour I looked at it. After fixing numerous bad solder connections and a faulty pot the overdrive works perfectly but the normal channel is down in volume a lot. Looking at the schematic I have tested every component in the entire circuit that is used for normal but not overdrive (out of circuit too) and none found. has changed the tube to a 12AT7 but even with the right tube it’s still quiet. Absolutely stumped, first amp in 18 months that I can’t fix. Doh!!
@cowasakiElectronics
4 жыл бұрын
I even socketed and swapped out the opamps
@dembydish
2 жыл бұрын
Hi D Lab, a long time viewer here. I stupidly plugged a 110v Marshal 8040 Valvestate into a 240v supply. Fuse blew, and now the gain channel works quietly but is very distorted. The normal channel seems to work better but not fully healthy. Any idea what is likely to be damaged and may need replacing in this scenario. Any advice is welcome. Thank you.
@djfrank59
8 жыл бұрын
These hybrid Marshalls are problematic with bad solder joints. (even on their all tube amps. I've found numerous cracked joints, partially due to the use of lead -free solder. It's not flexible like the good 'ol 60/40. The send/receive jacks are always a problem. I've found many of those jacks cracked or the contacts corroded. Great video as always! :)
@d-labelectronics
8 жыл бұрын
+Frank Ferraro Yes Sir, I agree. Solid state amps are not my favorite to work on, however, I try to support the local guys. Obviously these amps wont be around in 50 years like the classic tube rigs! Thanks for your kind support on my videos.
@silasfatchett5693
7 жыл бұрын
Lead free solder. One of the 'benefits' imposed on us by the European Union.
@user-qm7nw7vd5s
Жыл бұрын
I have a very similar amp, combo 12AX7 tube and solid state, a Hartke 100. Works fine, but despite repeated and thorough pot cleaning (spray into slots on back coves), the volume, gain controls are still scratchy. Any ideas? Great channel, btw. Just subscribed and liked. 👍
@ragedmachine
7 жыл бұрын
Super Like! and subscribed. I have a VS100 Valvestate with a very evident HUM, gets louder on Overdrive Channels. Am I looking for cracked solder joints too? Will open her up tonight..
@kneurotic138
5 жыл бұрын
Did you figure it out? Mine just developed that problem
@robertphillips597
5 жыл бұрын
I just got one of these " the 100 watt model 8400 I believe?" The guy bought it from a pawn shop for 140.00 and it started cutting out and making a weird modulated sound every time a note was played.. the guy was fixing to throw it away. I said hey why don't you let me take a look at that, it may be something simple like the 12ax7 went bad? He said here take it.. anyway I don't have any real experience working on electronics, amps etc.. so I got it home, sprayed some cleaner in all the pots and jacks and it started working without cutting out, but still had the modulating going on with every note played, so I looked at the 12 ax7 it was fine.. I was about to give up on it but then I said oh well, I'll just take the entire main board out and see if I can figure it out and maybe learn something new, "as I've always wanted to build some tube guitar amps for fun." I started looking at the transformers they didn't look burned up or anything, but I don't have any way or know how to really test them.. so then I started looking at the circuit board for broken solder joints etc.. I ran across two 50 volt capacitors that were extremely loose and wobbly. So I reheated the solder on them and now it works perfect. But I did notice some pretty bad soldering and expect to have to re solder more of the components in near future.. do you have any advice for someone who is a complete beginner and wants to learn how to build simple tube guitar amps, like maybe a champ circuit, or 18 watt plexi etc.. Something that will get decent warm cleans to run pedals through "pedal platform" etc.. I know some of the safety precautions, lol like don't stick your tounge on capacitors, transformers etc.. but guitar amp circuitry really interests me.. any books on building this stuff and how it works from a beginner's stand point of view would be greatly appreciated.. thank you in advance..
@DarkCyder9
6 жыл бұрын
Thanks for the video. I overlooked the output jacks on Mine. Just blasted em with some contact cleaner. Going to see if that fixes it. If that's not it, it's the tube.
@ZZEROO99
3 жыл бұрын
considering purchasing one of these amps used thanks for the video.
@wojciech_migda
7 жыл бұрын
As always very informative! Thanks a lot for sharing Your experience and knowledge helped me get my Marshall SLP 1959 back to great shape (the 1ohm resistor from tubes to ground was bad).
@peterglennie8391
5 жыл бұрын
Thanks so much for this video. I have this exact amp (VS65R) and am going to give it a service soon, check it over and probably replace the tube. Do I still need to bleed the filter caps on an amp like this to make it safe, and do you know if the tube (an ECC83) will need biasing at all? Thanks for any help.
@jeffpavlet1785
7 жыл бұрын
I had exactly this problem with this exact same amplifier. Great amp though.
@eazyrider6122
3 жыл бұрын
Great video i would have liked to have seen what to remove to get the board out?.
@anvil777
8 жыл бұрын
Great video Terry thanks for sharing Your knowledge.
@DavideZanellaDrum
7 жыл бұрын
Thanks a lot for your videos, very helpful
@johncunningham5435
8 жыл бұрын
Do you use 60/40 solder for the repairs? and second, what type of soldering iron do you personally use? "great video"
@nickdfx2208
7 жыл бұрын
Thanks Terry, love your work! Im currently working on a marshall valvstate AVT 50H, very similar to this 65, it was given to me as a gift. I like the amp alot but Im interested in modifying the clean channel to be cleaner, i know its an unusual thing to do, it seems i can find tons of info on mods for more gain, but i cant find anything on mods for making the clean channel cleaner. The overdrive channel is great the way it is but that clean channel just cant get good volume without turning up its gain knob. Got any tips for me? Much appreciated.
@alastairwoodford5180
6 жыл бұрын
Brilliant video
@lucasich
4 жыл бұрын
thanks for sharing your knowledge master.
@keithlamb578
5 жыл бұрын
Great video. I have one of these amp's. And it has developed a very loud hum even with all the volume off and nothing plugged into it. Any suggestions what the problem may be would be greatfully received. Thanks
@pietroprestininzi
4 жыл бұрын
I have a vs230 with the same issue, I'll try to open and replace the tube
@kerigregory7664
4 жыл бұрын
What about the crackely pots the ctscky noises ones that make a racket when you turn them. What method do you use for that?
@MrAndfio
8 жыл бұрын
I like this video as i have one of these amps,,i also have a Carlsboro Cobra 90 bass amp that keeps blown a resistor and i cant find the reason.Is there a way i can send you the schematic and show the location of this resistor,and maybe you might have some sort of idea what i should do.
@KristopherNoronha
2 жыл бұрын
I have been given a Marshall VS15 that's missing the transformer in the amp. I can't figure what rating (ie what output voltage) transformer it needs. Any pointers?
@alfredthompson3022
3 жыл бұрын
I have one of these Marshall amps and when hooked up to a speaker and turned on the Speaker cone jumps out and no sound .I suspect the transformer. How much are the transformers for a amp like this please and can I put it in myself Thank-You !
@johnsimms3957
8 жыл бұрын
Great job Terry! I have a question. My tube Marshall blew a fuse the other day. So I went to Radio Shack and bought some replacement fuses. I then replaced the bad fuse. ( I also changed the output tubes). However after putting the amp back together I found out the fuses were made in China. I haven't powered up the amp yet. Should I be worried?
@d-labelectronics
8 жыл бұрын
+John Simms Hi John, Of all the components that China makes, fuses are probably OK. I do not trust their tubes. Use the Russian re-issues. I have also used some China transformers with success. TD
@johnsimms3957
8 жыл бұрын
Thank you Terry.
@axeloberg9596
5 жыл бұрын
Very informative A++
@johncollins6023
4 жыл бұрын
I have a Marshall vs265 valvestate that would run for a few seconds, then quit. Now when I push the power button, nothing happens. I'm thinking the switch or fuse is bad. Any thoughts on this would be appreciated.
@AL197845w34832479823
7 жыл бұрын
Hi great channel I have a question if I connect an ipod to the input can I use the amplifer to listen to music(I know it's mono) I just want to know.I also know that I can use the back connection I want to know if works on the front input thanks
@fabriciomendes25
5 жыл бұрын
Sir, thank you for the patience. Thank you for those great lessons you're always giving to us. My amplifier is burning the preamp TL072 .. when I change it, the amp works perfectly for a little bit, then it starts to get hot (the tl072) and fail... I've noticed that those two white 330ohm resistors are getting too hot... hot in point hurt the finger on touch.. Can you give me a light here?
@NOXFPV
8 жыл бұрын
I have a Marshall AVT50 x it had very low volume on both channels. the clean channel was even lower than the distortion channel. I replaced the valve and now its very loud on the distortion channel but the clean channel is noticeable lower. If I turn down the bass and treble all the way on the clean channel and the volumes all the way up you cannot hear anything. with both volumes and bass and treble all the way up it sounds like a 5 or ten watt amp. the distortion channel sound like 50 watts. Any ideas. I have done all the basics like lose or corroded solder joints. All jacks are clean and making proper contact. It also seams to take a long time to heat up. the tube / valve is in good working order. Any ideas?
@bart99gt
5 жыл бұрын
The geniuses that decided that it was a good idea to not put all of the pots on their own board should be required to work on these for their eternity in hell.
@joemarino6944
7 жыл бұрын
good job, from KC2OCC
@PoCiLga
8 жыл бұрын
Hello, Sir, I'm from Brazil, and I have the same amp as this, I'm having trouble, I need to raplace the potentiometers, but down here I just can't find them!! can I raplace for anoter model of pot? I just can't find it anywhere!!
@d-labelectronics
8 жыл бұрын
Hello, Try antique radio supply in AZ, USA
@rockcastlemusic
7 жыл бұрын
i have the same amp, its nice sounding amp but after around 10-15 mins after turning it on amp starts to hum. what could be the problem.hums only when cable is plugged in. used good cables still the same.
@d-labelectronics
7 жыл бұрын
Sounds like cracked solder connections. Would be best to pull the circuit boards and inspect under bright light + magnifying glass, look for ring cracks around the jacks/pots/power resistors/large capacitors, anything that could easily fatigue. TD
@mattgibson1738
7 жыл бұрын
question.....i have one of these and when i switch from clean to od there is a complete drop out in sound for like seven seconds until od channel kicks on....any idea what this could be? any help would be greatly apprecieated.
@silvioalvim
5 жыл бұрын
i have a problem when switch channel too... but in my case, sound don't drop out, but make a noisy pop and OD channel sounds a little weak when gain pot is under 5. I have been used in this configuration for years, but now the OD channel kill the sound quickly, like a guitar with low sustain (is not my case)
@micahmingusyoutube
4 жыл бұрын
Ok can someone please help I have a Marshal vavlestate 150 h thats having problems im not getting any audio out of it and when I power it on the power buttons lights up when turned on so I checked the fuse and it was fine . After I took out the board to see if I could see if anything was funny looking I noticed that the fan doesint work either its like there is not any power going the amp at all .. But the power button lights up lol
@chrisofknives
7 жыл бұрын
i have vs100 head. has a bad solder joint i need to fix. how do you remove the actual board. i know i have to take the nuts off but there are also three white plastic cone shaped pieces that attach to rivets that connect to the amp housing.
@getawayyy1105
7 жыл бұрын
chrisofknives never repaired an amp but try googling schematics
@DarkCyder9
6 жыл бұрын
Not sure about the VS100, My 50w combo the board just pops off the rivet looking tabs. Pops on just as easy.
@shutterspine
8 жыл бұрын
i own a valvestate, it came with problem. maybe you can help. it turns on, but after playing for about five or ten minutes, the sound dies, comes back, dies, comes back. id really like to use this amp, is there a culprit? how can i fix it? i live in po-dunk montana-there is no one that repairs amps- so its up to me. thank you.. remember what orson wells used to say about wine!!!
@d-labelectronics
8 жыл бұрын
Hello, That issue sounds like 1 of 2 things. 1. bad solder connections on the PCB, usually in the power supply area. Circuit board will have to be carefully removed and flipped to see. Use a bright light and magnifying glass. 2. Bad connection on the send/return 1/4" jacks. Usually it is the positive wiper on the return jack. Simply press on it with a toothpick when the sound cuts out. If it returns, clean the contact, if still intermittent after cleaning, the jack could be too corroded to save and will have to be changed. Hope this helps.
@shutterspine
8 жыл бұрын
thank you so much. the amp is an 8040 valvesate. ive taken the control panel out, ill remove the circuit board and check the connections--thank you for your help. i only paid $10 at a garage sale. thanks again and have another glass of vino!
@zupaxis
8 жыл бұрын
If i make a video of my amp osculating could you maybe help me out.. i have electronic background but I cant figure out what the co-prate is and yes its a valve-state... But i am going to try your advice and just poke around... So ill try and explain whats happening on clean channel i get very little sound output when i go to crunch no sound... When i go to Overdrive channel i start getting the Oscillating and a really high pitch sound...
@zupaxis
8 жыл бұрын
Most people would just throw this out but In ten years or so they well be gone and maybe worth some money :-D
@kungpuk5186
5 жыл бұрын
Vintage? Makes me feel old as i bought my vs65 new..
@runtfan71
5 жыл бұрын
I just went to the comments to say the same thing. I guess we're vintage as well...
@j.a.rodriguez3838
4 жыл бұрын
This is my new favorite channel! I have low hum on the clean channel that’s driving me nuts on my VS65R.
@AL197845w34832479823
8 жыл бұрын
Hi I'm trying to fix an amp like this one.The amplifier power up but no sound and there is hum.So under those resistor there is some burn those resistors go extremily hot after a few second.I checked the connection but they are ok.Can you please help me thanks?
@d-labelectronics
8 жыл бұрын
Hello, I would guess that you have shorted output transistors
@AL197845w34832479823
8 жыл бұрын
Wow you have already answer.so I have checked the resistors and they mesaure 330 ohm 1 and one 327 ohm(they are good right?)S do you think that I need to check the power transistor,the ones attached to the heat sink?
@d-labelectronics
8 жыл бұрын
Yes, those are the ones to check
@AL197845w34832479823
8 жыл бұрын
You are great thank you again.So i pull out the transistor and this are the value.for the t64a I get .470 .553.For the t65 I got 4 value(is that correct) .452 .472 .572 .623. In case I need to replace I found on internet that common substitue are tip 142 147 are those ok?thanks again
@d-labelectronics
8 жыл бұрын
Hello, if those values are ohms, like .470 ohms, the transistors are shorted. The best way to test the transistors is in a diode check function. Does your meter have that?
@waynewayne3709
4 жыл бұрын
They always use them cheap nasty pots just to save cost.. Even the output heatsink should be 1 long heatsink not 2 small half sized bits..
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