Marshall 3203 Artist ?

[charvel750]

Guys, what are the white things called that link to the output tubes? The white rectangle looking things labeled ISKRA on them...I've got a broken one and need a replacement. Are they "resisters"?

[jgcable]

They are wire wound power resistors.

[charvel750]

Thanks, any idea where to buy replacements? And I assume you just solder them to the board, right? What causes them to fail?

[jackson1]

Joe, heat, age and physical shaking will make them fail, but they take quite a bashing before they give up. Yes, you just solder them to the board. They can be had almost everywhere (at least in europe).

[jgcable]

Thanks, any idea where to buy replacements? And I assume you just solder them to the board, right? What causes them to fail?

You can check online at places like Digikey and Hamilton Avnet. Just do a search for wire wound power resistors. Companies like Ohmite, Dale, Clarostat and Memcor make them. They are very popular and easy to get. All the info you need is printed on the top of them.

[charvel750]

Thanks guys, the actual resistor I need was one used by Carvin in their Valvemaster. It says: Colber 350 ohm 5% CW5PCR. So in my search I know it's 350 ohms, and 5%, but what is the wattage? Every site is asking for wattage in addition to those values. These were used in a 100 watt tube head...

[jackson1]

Sounds like a 5watt resistor.

[Spivonious]

Yeah, if I had to guess "CW5PCR" probably means 5W power resistor with some Cs thrown in for good measure.

[jackson1]

Clear as mud Seriously, 5, 7 and sometimes 10 watts are used in power amps and the picture Joe posted shows 4 watt type, so...