Scott 299b repair

[bkall]

I need to replace the 3 taller ceramic caps next to the power supply but i do not know what to replace them with. Please advise one of them gets hot fast even with the variac

 

[drew_t]

If you're talking about the tall white cylindrical things that stick up through the chassis, they're resistors, and they're supposed to get hot.

 

[bkall]

ok 1 of the 2 taller ones gets much hotter than the others. It is the last one in the series coming off the 5ar4. Is that normal?

 

[primosounds]

ok 1 of the 2 taller ones gets much hotter than the others. It is the last one in the series coming off the 5ar4. Is that normal?

If your amp is operating correctly then, the resistors are doing their job. Some maybe hotter than others, which is ok.

 

[bkall]

thank you

 

[trainbuftony]

If you want to investigate further check the electrolytic capacitor after that resistor, Has it begun to short? Most likely there is no problem, those resistors get very very hot under normal operation. If yours don't smell of nicotine when hot, be thankful.

 

[vaathi]

Somewhat related to the Resistors question. Where I can find replacement for one of these resistors other than from donor unit.

 

[bberkom]

I'm not sure you can find the tall cylindrical type anymore, but you could probably identify the one from the schematic and match the specs with a new leaded resistor. Mine were still in spec and operational. They not only see a lot of voltage but are also located next to the hot PT and hot rectifier tube, so they get real hot! If you wanted to replace that resistor with another type, you would have to be strategic about how you mount it so that it's secured, leads are not exposed above the chassis, and that the resistor was still out and away from other components. Any resistor you put there is going to get hot.