Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: JustMike on September 11, 2022, 09:11:10 am
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I placed an order for one of these a while back and they called me and said they were on back order due to some incorrectly manufactured boards. A couple of weeks later, I received it. I installed it as I have done before in a 2204 clone. It doesn't pass audio and I can't find a schematic. BTW, this PCB is silked version 3. Snooping around, I noticed that 2 pairs of resistor values are incorrect.
Looking at the attached picture, there is a row of resistors starting in the lower left that has the values printed on the board. If you count from L to R, values 4&5 are swapped as are 6&7.
It's Sunday, so I can't call MOJO, but it's possible they were deliberately swapped because the board was printed incorrectly as noted above...just a thought. But I also thought some of you here could make some educated guesses about these values. I assume they tie to the transistors or FET's they are mounted close to.
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In the pic, it "looks" like the left leg of the 100pF cap in the center of the photo is not soldered. Hard to tell.
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I would ask for a replacement board. Otherwise, swap the resistors so they agree with the silk screen print.
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In the pic, it "looks" like the left leg of the 100pF cap in the center of the photo is not soldered. Hard to tell.
Agree. Maybe it's connected but the hole is barely filled. If you look around it appears many of the solder joints are questionable.
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If you look on the website, that sample board has the same mismatch of labels and parts.
https://www.mojotone.com/Mojotone-Discrete-Hi-Voltage-Series-Effects-Loop-for-Vacuum-Tube-Amplifiers
https://www.mojotone.com/products/5352106_01.jpg
Call them on it. If they are shipping mis-marked PCBs they do nobody any favor.