Intermittent faults are always difficult to find. I have a plastic crochet needle that I use to tug on wires and poke components with so I can try to locate loose components. It's a great tool and it has helped me find a lot of bad connections and "ghosts". Always look for the obvious first - it saves a lot of time! Even if a loose wire wasn't the original problem, it still WAS a problem, or at least would be very soon.
@@stuartukguitarampguy5830 I'll have you know that I am a TOP ranked amateur 😉 😏 😜 Someday I am hoping to make enough money repairing amps to be able to afford to buy a proper chop stick 😅
Your one cool cat Stuart. I really enjoy your tactics to get to the root problems. I also very much like all your videos. I hope to visit your shop one day with a few of my amps. I am in the US. It has always been a dream of mine to visit the UK. Take care and hope all is well with you and your shop.
Great teaching! Thank you very much. Will appreciate some video about shop tricks and test inventions: Variac, oscilloscope measurements, dummy load construction... thanks!
Love your channel and subbed. I have a similar problem with a Peavy Stereo Chorus 212. Turn it on and the loudest ripping noise happens. It has been sitting for about 5 years and going to have a look at it someday. I am rebuilding my recording studio right now.
Great video! , had the same problem with my jcm900 4501, a few years ago. when heating up, a solder joint of the tube chassis would disconnect a bit. Storetechnicians couldn't find it, or were to lazy to take it apart, who knows.
Another great video many thanks!! How do I contact you about my jcm 900 combo that has got some issues with channel A? Takes rather long time to warm up and to sound good. Many thanks again
At 6:08 when you mentioned that you felt lazy because you didn't want to take the board out, you then mentioned re-soldering the blue wire on the tube socket and that re-soldering had fixed the crackling when touching the wire. Only one problem with that, it wasn't that tube socket where the wire was crackling, it was the one to the left of it. Second error is that at 8:25 when tapping the valve, you said it was the same socket that you re-soldered. No it wasn't, it was the one to the left of it when looking from the top of the amp, i.e. the view at 8:25. I would have thought that someone of your skill and knowledge would have got that right. You did sort of correct it later in the video, but it should have been spotted straight away!
I once had a PC that did not work inside the case. I assembled it outside, perfet. Back in the case, beeps and no boot. Found out that there was a cap shorting to one of the mounting studs. It is worse when you get it in after fixing and it does not work again.
Wow! I purchased a used JCM Marshall 4501 combo from Guitar center. I received it today from UPS. Plugged the amp power cord in and made sure the gain and volume knobs were all turned down. I turned on the amp w/ out the guitar plugged in and less than a minute it started making the same exact popping noise as the amp you are demoing. It started getting louder. I plugged in my guitar and played some chords but no sound came out from the guitar except for the popping noise that was already popping. CRAZY.... any help would be greatly appreciated. Thanks
Hi how can I enjoy the Marshall JTM45 At home I am at a crossroads whether to sell it and buy a small amplifier or is there a possibility to save our friendship and keep it thanks
Stuart enjoying your channel immensely … BUT at 5:50 you demonstrate blue wire noise from v2 pin 9. At 6:30 you have resoldered blue wire v3 …. and at 10:40 you are ( unsurprisingly ) back to v2. Cmon, spill the beans… you rewired the wrong blue wire ( v3 instead of v2 ) initially didn’t you. Yes there may have been a dry joint on v3 blue, but v2 blue was the culprit all along wasn’t it ? Please this is not criticism , just a gentle jibe at what looks to be a slight mix up there. Keep sharing, this is great content.
A case of poor quality control. No matter how many name stickers one attaches to the amp, this amp should have never left the factory. In general it is surprising with what manufacturers get away with in the guitar sector. In other sectors such as automotive, home appliances etc. you would have already been wiped from the market. I had one of these ordered. Put it out of the box. Plugged it in. No sound. Dead on arrival. Send it back.
An old tech head from the USA. Really enjoy your channel. One of my favorite.
Thanks David!
Intermittent faults are always difficult to find. I have a plastic crochet needle that I use to tug on wires and poke components with so I can try to locate loose components. It's a great tool and it has helped me find a lot of bad connections and "ghosts".
Always look for the obvious first - it saves a lot of time! Even if a loose wire wasn't the original problem, it still WAS a problem, or at least would be very soon.
Only rank amateurs use plastic crochet needles. Top professionals like me use a chopstick...
@@stuartukguitarampguy5830 I'll have you know that I am a TOP ranked amateur 😉 😏 😜
Someday I am hoping to make enough money repairing amps to be able to afford to buy a proper chop stick 😅
Your one cool cat Stuart. I really enjoy your tactics to get to the root problems. I also very much like all your videos. I hope to visit your shop one day with a few of my amps. I am in the US. It has always been a dream of mine to visit the UK. Take care and hope all is well with you and your shop.
Thanks very much. You're welcome to visit if you come over.
Great teaching! Thank you very much.
Will appreciate some video about shop tricks and test inventions: Variac, oscilloscope measurements, dummy load construction... thanks!
Ok thanks!
Love your channel and subbed. I have a similar problem with a Peavy Stereo Chorus 212. Turn it on and the loudest ripping noise happens. It has been sitting for about 5 years and going to have a look at it someday. I am rebuilding my recording studio right now.
Thanks for subbing. Good luck fixing it!
Great video! , had the same problem with my jcm900 4501, a few years ago. when heating up, a solder joint of the tube chassis would disconnect a bit. Storetechnicians couldn't find it, or were to lazy to take it apart, who knows.
Great one as usual Young Stuart!! (Hope you can get away from these problem amps problems when sleeping at night!) ha ha!
Thanks! Yes, I I rarely dream of amps thank goodness.
Great video - very informative!
Thanks Matthew!
Good job!
marshall cold solder joints. the woes of lead free solder
I have s secret stash of leaded soldeer which will see me out!
Great video!
Thanks!
It doesn't turn on booster chanel light Marshall jcm 800 lead series 2210 but does work. What can I do?
Another great video many thanks!!
How do I contact you about my jcm 900 combo that has got some issues with channel A? Takes rather long time to warm up and to sound good. Many thanks again
Hi Jan Thanks for the feedback! My contact details are always at the very end of each video. Thanks
The valve is loose inside the base socket. Tighten the inside socket connectors
At 6:08 when you mentioned that you felt lazy because you didn't want to take the board out, you then mentioned re-soldering the blue wire on the tube socket and that re-soldering had fixed the crackling when touching the wire. Only one problem with that, it wasn't that tube socket where the wire was crackling, it was the one to the left of it. Second error is that at 8:25 when tapping the valve, you said it was the same socket that you re-soldered. No it wasn't, it was the one to the left of it when looking from the top of the amp, i.e. the view at 8:25. I would have thought that someone of your skill and knowledge would have got that right. You did sort of correct it later in the video, but it should have been spotted straight away!
Hi David tbh it's been a while now and I can;t remember. I do make mistakes from time to time, particularly when trying to film at the same time.
Hi, would you have a schematic of this JTM45 MKII you could share?
I once had a PC that did not work inside the case. I assembled it outside, perfet. Back in the case, beeps and no boot.
Found out that there was a cap shorting to one of the mounting studs. It is worse when you get it in after fixing and it does not work again.
Ugh, nightmare. Needless to say I've had many similar things!
So it's either a cathode or plate solder connection...
Wow! I purchased a used JCM Marshall 4501 combo from Guitar center. I received it today from UPS. Plugged the amp power cord in and made sure the gain and volume knobs were all turned down. I turned on the amp w/ out the guitar plugged in and less than a minute it started making the same exact popping noise as the amp you are demoing. It started getting louder. I plugged in my guitar and played some chords but no sound came out from the guitar except for the popping noise that was already popping. CRAZY.... any help would be greatly appreciated. Thanks
Ok well I think that's definitely a return job! I hope you manage to get it sorted.
@@stuartukguitarampguy5830 Yeah I guess it would probably cost to much to have it repaired. Thanks so much!
Hi how can I enjoy the Marshall JTM45
At home I am at a crossroads whether to sell it and buy a small amplifier or is there a possibility to save our friendship and keep it thanks
Hi It's a good amp so I'd keep it if you like it.
no grid stopper on the input? or is it at the jack?
Hi John,. Not sure tbh.
Stuart, was this due to age or poor workmanship? Maybe something else? Nice to see this issue as it seems to be fairly unique. Thanks for the video.
That sounds like my old 1952 BSA 125cc Bantam 😀 😉
Ha ha!
the noise sounds like the drummer from motorhead.flabby out of time kick drums ha ha
Stuart enjoying your channel immensely … BUT at 5:50 you demonstrate blue wire noise from v2 pin 9. At 6:30 you have resoldered blue wire v3 …. and at 10:40 you are ( unsurprisingly ) back to v2.
Cmon, spill the beans… you rewired the wrong blue wire ( v3 instead of v2 ) initially didn’t you. Yes there may have been a dry joint on v3 blue, but v2 blue was the culprit all along wasn’t it ?
Please this is not criticism , just a gentle jibe at what looks to be a slight mix up there.
Keep sharing, this is great content.
Hi Mike Tbh I really can;t remember as this was a while ago. Glad you're enoying it!
A case of poor quality control. No matter how many name stickers one attaches to the amp, this amp should have never left the factory. In general it is surprising with what manufacturers get away with in the guitar sector. In other sectors such as automotive, home appliances etc. you would have already been wiped from the market. I had one of these ordered. Put it out of the box. Plugged it in. No sound. Dead on arrival. Send it back.
Hi Michael Yes it's defintely not good.
Alza il volume minuto 6.30 amplificatore funziona sono solo le finali
Great video!
Thanks Boza.