JCM 2000 TSL 601 MARSHALL AMP TURNS ON NO SOUND TUBES DONT LIGHT

I suspect it's your input jack if it stops working immediately and comes back immediatly rather than fading in and out. Give it and any other jacks a good cleaning and see if it helps.

Make sure speaker cable works and is connected then check fuses. If it has a master volume, make sure it's turned up.

How do you have the DIP switches set? That controls the voltages.

Likely the filter capacitors have a problem. Best to take this in for repair... it is ODD that there is noise with the standby switch is in standby... That makes no sense... In standby it appears that power is removed from the power amp high voltage so nothing should come through the speaker... Unles maybe one off the power tubes had a total meltdown which should have blown the fuse.

Only 6 wires are used by the amp. Tie the brown wire to the metal frame to act as shielding if anything. You will probably find that the brown wire either connects to the shell of the connector or to nothing.

The sound level output is a true measure and unless you can compare specifications between units, you are probably listening to salesmen who want to sell you product.

The power level rating is OFTEN falsified and a LOT of the actual sound level performance depends upon the speaker used.

You should get a sound level meter to compare amps.

Remember to NEVER run more than 100 Db to avoid legal liability for hearing damage. I know several musicians who are nearly deaf now from being exposed to high levels too long. You can look up what the govt limits are now with Google.

The 2000 should EASILY reach the 100 Db level.

I doubt that you have checked the tubes... tube checker's are rarity now and you can't look at a tube and "tell it is alright". If you leave the footswitch out does it do the same thing?
The probllem could be many things...and you haven't mentioned how you tested the items you are exhonorating. A common problem is a noisy or broken INPUT jack. Musicians forget to loop the guitar cord through the handle and the cord gets moved and yanked sideways wearing the jack and often breaking internal parts. Yjos also goes for the cord to the footswitch as well. Cords and connectors/jacks are the common problems. Less common but frequent are damaged volume control pots due to damage when handling... including broken solder where these attach to the circuit boards.

First thing is that if you bought MATCHED pairs of the EL34's a COMMON mistake is to install the pairs wrong. Correctely install a pair as the OUTSIDE tubes of the line and then the remaining pair as the middle two tubes of the line of tubes before biasing.

Funny thing, I just ran across this problem you have with a Bedrock brand amp that uses the same configuration as your V3 tube does. This is really a stupid configuration engineering wise as they tie a plate at high voltage to the grid of the second stage in the tube as a cathode follower, This means that the second section has the cathode at a reasonably high voltage relative to the heater with wide audio swings on it as well... Tubes are NOT designed to work that way and result in noisy behavior, One would have to select tubes that have very low heater to cathode leakage in the second section of the tube... What you are seeing is the result of very poor engineering practice. Marshall is probably testing tubes for the leakage and branding them as such...

I think that designers of this circuit have NOT had experience with tubes and have applied transistor type designing to this use... it is plain stupid and myself I would re-engineer the circuit if it was mine or build a tube tester capable of measuring the heater cathode properties to select a suitable tube to use.

Probably the bias is set wrong... Please note that when installing MATCHED pair tubes, the tube pairs usually go at opposite ends of the strings, that is one on either side of the center of a set of four.

Very nice amp!

First off, is the amp getting sufficient power? An unreliable AC current from your wall can affect the performance.

Have you tried the amp with a different speaker? Checked for a loose connection from the amp to the speaker? Is it the correct ohms rating?

Second, are you experienced in electronics? The problem could lie in a faulty solder connection, a bad component, etc.

If you are not confident in opening the amp and troubleshooting it yourself, take it to a audio repairman. Marshall's are some of the easier ones to fix.....