No voltage at position 18 Mojotone 18watt tmb
- Thread starter Martinoils
- Start date
Huh? What's marked as 18 is a grid wire, and it even shows 0 on the voltage chart.
If you got a pop or crackling moving the OT primary wires, check your solder joints at pin 7.
Paul G.
Friend of Leo's
There isn't supposed to be any voltage there. You need to check your OT connections since that's what you disturbed. Reflow the connections on pin 7 on each power tube. Sometimes a joint looks good but the wire isn't bonded to the pin.
Sometimes I flap my wings and move my beak.
Martinoils
TDPRI Member
I’m so confused on this build, you’re absolutely right and I’m embarrassed as hell. I get no sound and can’t figure it out
Next I’ll post photos of my amp.
Martinoils
TDPRI Member
Thanks I’ll try that
Now I realize that 18 shouldn’t have voltage
Don't stress. You'll get it resolved. Finish checking your voltages against that chart first.
Martinoils
TDPRI Member
Martinoils
TDPRI Member
Hi, newbie builder, almost there but very low volume on two normal channels the master gain channel has more volume but maybe 60-70% of what a 15 watt should have .
Here are my voltage readings
1) 11.1
2) 324.6
3) 324.5
4) 0
5) 182.5
6) 281.1
7) 0
8) 27.6
9) 47.9
10) 45.1
11) 147.2
12) 147.8
13) 0.8
14) 0
15) 228.9
16) 2.4
17) 249.4
18) 0
19) 188.0
20) 142.0
21) 1.6
22) 0.8
Here’s the chart
Here’s some photos of my build
Any help I can get would be so appreciated!
Thanks for your help
Here are my voltage readings
1) 11.1
2) 324.6
3) 324.5
4) 0
5) 182.5
6) 281.1
7) 0
8) 27.6
9) 47.9
10) 45.1
11) 147.2
12) 147.8
13) 0.8
14) 0
15) 228.9
16) 2.4
17) 249.4
18) 0
19) 188.0
20) 142.0
21) 1.6
22) 0.8
Here’s the chart
Here’s some photos of my build
Any help I can get would be so appreciated!
Thanks for your help
Martinoils
TDPRI Member
Hi, reflowed pin 7 on all tubes
Much improved except that the volume is way off.
I posted a different thread under Mojotone 18watt tmb volume issues with voltage readings, chart and photos if you care to have a look.
5 & 6 seem to be way off.
Thanks for your help
Jon Snell
Tele-Afflicted
All this will do is confuse people.
Martinoils
TDPRI Member
Sorry
Martinoils
TDPRI Member
I have triple checked the wiring for sure and the voltage readings are off at position 5 and 6 compared to the voltage chart on the layout diagram I posted. I just finished re soldering all those connections with no change
Thanks
Thanks
andrewRneumann
Friend of Leo's
I do believe I’ve spotted a missing jumper on pin 3 to pin 8 of the LTP.
dan40
Friend of Leo's
From reading the earlier post I see that you have reflowed pin 7 on the sockets. Many of your turrets also appear to be lacking solder which could lead to poor electrical contact. If you are having trouble getting good solder joints on the turrets, you may need a larger tip for your iron to help heat them properly.
I'm scoring Andrew a hit. Martinoils, you know which tube is the LTP? Heh, the one that's supposed to have a jumper from pin 3 to 8. 
But that's V3 if I'm counting right.
But that's V3 if I'm counting right.
Martinoils
TDPRI Member
I can’t believe I missed that! Thanks so much!!!!!
Martinoils
TDPRI Member
Awesome but I’m sent that V2I'm scoring Andrew a hit. Martinoils, you know which tube is the LTP? Heh, the one that's supposed to have a jumper from pin 3 to 8.
