try to repair the 6j1 preamp, the same scheme follows the original, only there is a modification in the psu, the plate voltage is 28 volt ct, the output of the regulator is lm317 and 337, the transformer is 3 ampere, the heater uses 1 ampere, the voltage using 9 volts is turned down using lm2596 to 6.3 volt dc... which makes I'm confused, originally I used 12vac 1 amper (it's safe) then multipliered it to 28 vdc. When using a model like this, it often makes noise, so I modified a separate PSU (the hum is gone, the noise is gone). The question is why the 3 ampere transformer heats up quickly even though the regulator IC is still there. It's just cool.....maybe someone can help
![IMG_20230917_215709[1].jpg](https://www.diyaudio.com/community/attachments/img_20230917_215709-1-jpg.1214193/ "IMG_20230917_215709[1].jpg")
It would help if you would show a circuit diagram including the power supply. Your description is somewhat confusing.
If you modified it, and now it gets hot, you probably want to tell us what you modified.
Jan
If you modified it, and now it gets hot, you probably want to tell us what you modified.
Jan
1 trafo ct 3ampere output 30 vac ( not 24 vac ), second trafo used 1 ampere output 9 vac drop to 6,3vdc used lm2596 ...prob;em in trafo 3 ampere always hpt after used 5--10 minute
There may be a problem in the rectifier bridges.
I suggest to disconnect the load, disconnect the inputs to the regs.
If still hot, disconnect first the trafo to the pos rectifiers, if still hot also disconnect the trafo to the neg rectifiers.
In the end, if still hot, get a new trafo.
Otherwise, you have located the problem.
Jan
I suggest to disconnect the load, disconnect the inputs to the regs.
If still hot, disconnect first the trafo to the pos rectifiers, if still hot also disconnect the trafo to the neg rectifiers.
In the end, if still hot, get a new trafo.
Otherwise, you have located the problem.
Jan
