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Hello! I have a question that I hope someone can help me with. How would you go about cleaning spilled and dried coca-cola from a solid state guitar amplifier chassis chip? (It's a marshall avt) The mess is everywhere but the amp still works. I already cleaned a bunch with WD-40 and some fine toothbrushes. I've since read that WD-40 is bad for guitar amp chips.. what should I do to get it as clean as possible? Thank you!

Great job. Thank you. Vast amount of help.

I was (I’m) on the cleaner rabbit hole since I only have vintage audio equipment. But internet experts, are very vocal the ones in forums are much worse. I did the water and electronics, that drove them nuts. To make sure they went nuts I added a sonic cleaner. I tested full boards left them on the cleaner forever then tested each component no change what so ever. Anyway great channel. The dunning - Kruger effect is so prevalent nowadays, that is not worth the fight. Again great video and sub. 🎉

Thx for the wisdom,you're awesome

Hello Stuart, i just took your advise and added a 1ohm resistor in all four positions off pin 1 to 8 to ground and i got a good shock off the on off switch, when I took them back out the shock was gone. This does not sound right to me but it happened. This was on my 1959 super lead.kit by Mojotone. Which also works and sounds great.

Man you are awesome....I subbed.

Brill. Thank you for sharing very valuable knowledge that takes as you stated 50 years to obtain. and pieces of info can be passed on in 20 min or so.

My jcm 900 low bass very small cant reach..u have solution

Great Stuff and much appreciated. I have a 1999 USA Blues Jr (green board 1995 Rev B P/N 049305) purchased new by me in ’99 which is different from all the cream board Jr’s all over YT. Even with limited use as a bedroom amp the hot bias has has resulted in a few power tube socket pins to loosen from the tube board, thus the desire to cool the bias and continue using the amp. As I understand this board revision schematic, R37 and R31 make the voltage divider circuit and a parallel resistor across R37 would cool off the bias. Values per the schematic are R37-33k and R31-22k. What would the proper ohm rating of the resistor to accomplish this? I hope I have described all this properly. Thank you…

Great stuff. I purchased new, a USA manufactured BJ in1999 (Rev 2 1995 green board) and have been unable to find any information regarding a parallel resistor except mentioned here. As I understand R37.33k and R31.22k (resistors per the schematic) make the voltage divider in this board model so the 33k ohm R37 would receive the parallel resistor. What would be a reasonable resistor value to parallel across R37 to reduce the bias? Thank you...

I'd love to see you dissect a reverb recovery coil to see exactly where the open circuit occurred

If it's a blues junior, it's the screen resistor. You can lay money on it! 😅

Just bought a can of Deoxit D5 today, and on side of can says Unlimited uses ....."potentiometers" :)

All electric items run on smoke. Let the smoke out- it stops working. Great explanations of the components and circuits! I am getting ready to recap my BJ III and replace the tube valve board with one that has the bias components already installed. Seems I have lost most of my bass response. I may install the Hamonix EL84 valves as suggested by Jim from Seattle.

Thx for the great video. I have the same vibrato issue on a '79 Vibrolux Reverb. I will be replacing the roach. I thought it would be worthwhile mentioning that the reverb transformer appears to have been replaced on this Super.

Nicely done, Sir. I have a 68 SR drip edge with the same problem. After swapping the oscillator tube to no effect, I'm just about to pull the chassis. Ironic, isn't it, that when we were strapping young players, we couldn't afford these "dream amps". Now that we're old and retired, we can finally afford to buy one, but we can't physically carry the blasted things in and out of gigs, Lol. This 75 yr old (but still gigging) Canadian loves your channel. Thanks!!

That the person should have the decency to apologise to you and your viewers! Sadly these people will never! You destroyed that idiot completely! Well done Sir!

Just subscribed to your channel, due to your vast knowledge, class and you have a damn good channel!

Wow! You’re certainly thorough! My 65r valvestate had the same issue so I gave it away. Loved that amp as well!

Alza il volume minuto 6.30 amplificatore funziona sono solo le finali

Need your opinion, Hotrod deluxe when I have the channel switched pushed and the light shows and strum the guitar hard it cracks and the light goes out and volume drops and then the light comes back on like normal. But before the crack happens I see the light starting to dim. Any ideas?

Excellent video. Those amps are fantastic. I've a loan of a AVT 150. it is a monster.

I have a Fender Pro Jr.USA with a constant hum. It hums without or without the guitar plugged in. I really like the sound of this amp but unable to record with it due to the hum. Is there a fix or could you recommend a small Fender tube amp that sounds as good without the hum issue? Thanks so much for your time.

Great job and info! I have the same loud hum problem w/ my Fender Pro jr. I'm sure it has the same poor design as the blues jr. but I love the sound. Is there another fender amp of this size and sound quality that's made better and doesn't have this hum problem you could recommend? Thanks again.

Thank you sir! You are a amazing teacher

The best way to fix the jcm 900 is to just throw it in the dumpster

The skills are being passed on! I'm going to show my kid the bit about "legend up" on the caps. He's not into this kind of thing but it's wisdom that can be generalized. Thanks for these videos, very helpful.

It is not the carbon it is the binder that is used with the carbon to make the coating that is affected by D5. If you believe that D5 is safe and have had good experience that is all that matters keep using it. For me the gear I am working on is vintage, difficult to source replacement parts so I am going to not use it for my carbon track pots.

many thanks Stuart,, i now have a clean and quiet pots when i set up my amp.. great tutorial, thanks for your post

A technique i use to remove stubborn knobs is very similar to yours. Instead of a screwdriver try needle nose pliers, use one jaw on each side of the shaft and as the jaw gets thicker it works like a wedge and slides the knob off the shaft using even pressure on back of the knob . Works for me, you may want to give it a try

Great info here. Thanks for sharing. I have a 77’ or80

Those amps are very unreliable. I would stay away from them 😊

Superb explanation - thank you!

Please put on nitrile gloves before poking about on a live circuit! Accidental groundings hurt at best.

Hello Stuart.Can you tell me the value of the filter caps?and are they the same as the ones in the ultra chorus ?...can you supply them to me also..thanks Michael.

Hi I have one of these and the reverb doesn't work. If you 'slap' the amps body then you can hear the springs splash through the speakers. However, the guitar signal remains dry. I also don't know how to get in to look at the tank as it is mounted inside the amplifier chassis.. how do you part the clips open? Thanks...

This video fell right into my lap =) I just purchased the F5 a couple of minutes ago right before clicking on your channel, how bizarre. 👍 Mahalo from Commie Fornia TBD3.0 (Toothless Bull Dog 3.0)

bush league repair, pull pots back pull board back without disconnecting ribbons, repair like a pro. ohhh and diodes did their job, protected your most expensive component, PT

Try using a oil called ballistol. Works amazing

Thats a shame letting that amp go like that .

plus...i didn't hear usual swearing as i would be doing ( shhhh..LOL) . i've dome some pin isolating on an engle to get to pin 8....

i like your style!! i heat and lift using sloder like a lubricant.. then wick the holes...my desolder station...sometimes lifts pads...hate that. buddy has the 50 watt version...

Hello thanks tor that detail vid, I had many MM's and they came from the factory with Sylvania 6CA7 tubes, Blue and Yellow marks ;) please correct me if someone has some info about MM's 1974-78 first run tubes topic

What fuses do I need to get?

A year later and this genius is still telling people wrong information. Deoxit actually makes a product called *F5* for faders. Why would the *COMPANY* *THAT* *MAKES* the product, make a version specifically for faders vs the D5. *D5* says nowhere on the label that it is for faders and pots. *F5* Does say on the label it is for faders and potentiometers. D5 Contains mineral spirits which will loosen carbon particles. The track for faders and pots are made of pressed carbon dust. Is it a slow process...yes. But so is the planet going around the sun but we know it moves over the course of the 365.25 days This is all verifiable. But Stuart in his persistence will hold fast to what he believes. In spite of the fact that the company literally makes a product that is different in chemical make up that explicitly says it's for faders. I'm a scientist. I know this stuff. He's an old head sticking to old ways just because he hasn't screwed up yet

Just found this channel. 😊Very good. Question : i have a few solid state amps old, British when turn power switch on theres a loud crack/bang from speaker. I've used amps since 1980 and many have done this.. They work ok but i dont like thus turn on "crack * bang sound. Is there a way to stop this or does some cap need replacing? I thought i read years ago that there is a fix for this...? The amps i have that have problem is Vox Escort bass combo quite old.. Some caps were replaced about 20 years ago.. And other is that late 70's. Modelling amp built into flightcase by PA:CE, sorry i forgot name.. That really is scary bang on power up.. Its never been serviced and needs one.. Its missing the speakers and flight case box. Redmere is name, models a Marshall, Fender Twin and Vox its claimed and weird touch switches and built in sustain and chorus, flanger.. Thanks

In UK recording studios I frequented 35 years ago in London, Servisol 10 was ALWAYS used to spray mixing console faders. Im talking about the top studios here as well as the dodgy 24 track ones! Used to buy from Studiospares or Tandy (RIP), uk Radio Shack. Ebay sellers now. But beware crap Amazon cheap contact spray which is vile abd nothing like slinky Servisol 10. Maplins used to sell too but i think Maplins gone now.. 😢

I have found that a penetrating oil called Kroil by Kano industries is much better than wd40 for loosening stuck screws. Might be worth a try.

Thank you Stuart. I have the HD-130 Music Man head, I've never had to get into it but seeing your video has given me courage should the need ever arise to open it up. Great and informative video!

13:30 ... About the transformer AC ... The common 3 lead center tap transformers divide the Mains in 2 phases that are 180 degrees from each other. If you put the leads on these points the meter sums the phases ex: 20 + (-20) and the result is close to 0. This doesn't happen if one lead is on a fixed voltage.