Hi...just built a Mojo kit and have some problems.
I bought the Mojotone Kit because they had a good sale on....considerably cheaper than anywhere else and I got a damn nice custom tolex cab with it. I decided to buy the Tube Depot board and use it. I also upgrade the Mojotone caps with a side of Dijon. I wanted to change the layout a bit so I could install a Voltage regulator in the front panel fuse hole. I also added a switch on the back for Ohm selection of the output jacks. I also plan on putting another switch there for the negative feedback mod.
When I did the first power up, all was well with no shorts and dim bulb working as it should with rectifier tube and preamp tubes installed...good. However when I put the power tubes in, the dim bulb tester glows medium bright and stays lit. I have a low volume guitar sound, and there is no overdrive. Checked the wiring over and over, and all seems well.
I measured the VAC across each end of the heater winding (e.g.; i.e.: between pins 4-5 and 9 of the pre-amp tubes, and between pins 2 and 7 of the output tubes Here are my voltages with all tubes out;
V5 2&8=5.4vac 4&6=812vac
V4 & V3 2&7=7vac
V1 & V2 Heaters= 6.9vac
All tubes in, rectifier V5;
225Vac on pins 4 and 6 and 232VDC on 8 and 2
Filter caps;
242 210 and 183VDC from edge of board inward
Any comments are greatly appreciated. Thanks
I bought the Mojotone Kit because they had a good sale on....considerably cheaper than anywhere else and I got a damn nice custom tolex cab with it. I decided to buy the Tube Depot board and use it. I also upgrade the Mojotone caps with a side of Dijon. I wanted to change the layout a bit so I could install a Voltage regulator in the front panel fuse hole. I also added a switch on the back for Ohm selection of the output jacks. I also plan on putting another switch there for the negative feedback mod.
When I did the first power up, all was well with no shorts and dim bulb working as it should with rectifier tube and preamp tubes installed...good. However when I put the power tubes in, the dim bulb tester glows medium bright and stays lit. I have a low volume guitar sound, and there is no overdrive. Checked the wiring over and over, and all seems well.
I measured the VAC across each end of the heater winding (e.g.; i.e.: between pins 4-5 and 9 of the pre-amp tubes, and between pins 2 and 7 of the output tubes Here are my voltages with all tubes out;
V5 2&8=5.4vac 4&6=812vac
V4 & V3 2&7=7vac
V1 & V2 Heaters= 6.9vac
All tubes in, rectifier V5;
225Vac on pins 4 and 6 and 232VDC on 8 and 2
Filter caps;
242 210 and 183VDC from edge of board inward
Any comments are greatly appreciated. Thanks
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