Build Your Own Clone Message Board

Just putting together a JTM45 and I have no voltage on the green heater wires.........

Amp turns on, has some really weak/distorted sound from speaker when playing guitar through it.
All tubes appear to glow..........

Any Ideas?

TIA!!

Hi - welcome to the forum!

Please provide photos of the wiring.

If it were my build, I would make sure the green/yellow heater center tap wire coming from the transformer is properly grounded. Disconnect the green transformer heater wiring. Make sure no tubes are installed. Turn on the amp and measure the AC voltage (not DC voltage) from one heater transformer wire to the other. Make sure you aren't touching and bare wires with your skin and the wires are not shorting to anything metal. You should have somewhere from 6.3 to 7 volts AC.

_________________
MasterDelayer/Reverbrador/Ampaholic/TopJacker

Having trouble getting on the site......gott go thru phone
I have 6.5vac between the green wires.......
Amp turns on......sounds like crap.....play the guiter through it and it's very weak on power and clarity.

I see that there is a small split in the 16uF cap on the board.......dont remember seeing that before........possible?
How can I check it while it's on the board?

That’s good - the transformer is putting out the voltage it should. Reconnect the wires, pull all the tubes, and measure the AC voltages across the heater wires at each tube socket. Should be the same.

Is it possible that measured DC voltage before when you had no reading?

The split in the cap is troubling. I don’t think you should plug in any tubes until you can upload photos.

If you get the Tapatalk app, you can upload photos right from your phone.

_________________
MasterDelayer/Reverbrador/Ampaholic/TopJacker

I can feel it with my finger nail......pretty sure its split......will check the test point voltages later.......I believe the test point C is going to be way off if that cap is blown.......

Sent from my SM-G975U using Tapatalk

Checked all voltages at test points and they are normal per the intructions..........
Ot gone or power tubes?

Edit......now that I think of it........not so sure I had the speaker attached when powering up at one point.....cant remember..........blow the OT possibly?

Traveling today. Ill get back to you as soon as I can or someone else will chime in. Don’t despair! Still could be something else.

Please provide enough photos so that we can see all aspects of the build.

_________________
MasterDelayer/Reverbrador/Ampaholic/TopJacker

tried to do photos.......says its too large........

this is my first build........old hand at electronics......years ago......

I did make a mistake checking voltages though.......

CRossed the #2 pin and #3 on V4 power tube, #2 is the heater wire, #3 is the red wire from the OT.........got a spark and insulation burned a little.........think I might have burned out the OT........

Had to use a lot of green wire on V3 as I ran out of the other colors.

The 2 100K resistors off of the anodes (pin 1 and 6) on V1, they don't look soldered on the topside of the board like all of your other parts.

_________________
If practice makes perfect, and nobody is perfect, then why practice?

It hurts me to say this.. but.. follow me on facebook and.. instagram

Thank you.....done!

There are a few other terminals that look like they're unsoldered or not soldered well enough. Also, almost all your wires have too much bare wire sticking out to connect to terminals or whatever else. This won't make the amp not work, but will induce noise and act as weak points in the future.

If you were checking voltage, there shouldn't be any arcing. Maybe you had the meter on current, or had the probes plugged in the wrong sockets?

Sent from my SM-G970U using Tapatalk

It looks to me that you have the wires on pins 1 and 2 of V3 reversed.

Verify that and you should go back over all of your tube socket wiring with fresh eyes.

http://www.byocelectronics.com/jtm45-120v.pdf

_________________
MasterDelayer/Reverbrador/Ampaholic/TopJacker

Well......that was it.........put those wires where they belong and started right up sounding so fine.....except for a small buzz.
The guitar WAS fairly close to the amp at the time though.
Thank you to all that took your time and helped me out with this!!!

Nice job!

_________________
MasterDelayer/Reverbrador/Ampaholic/TopJacker

Good eye

Congrats on the build, Murph!

_________________
If practice makes perfect, and nobody is perfect, then why practice?

It hurts me to say this.. but.. follow me on facebook and.. instagram