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Kustom Commander fizzes out after 30 minutes of play (why?) [message #14121]

Tue, 27 July 2010 13:58

ethan
Messages: 5
Registered: July 2010

Junior Member

hey guys! My Kustom Commander fizzes out after about 30 minutes of rockin' out tuff. I figure something is over heating, but I am not sure where to start. i don't see anything damaged physically.
Does any one know where is a good place to start looking inside?
Is this a common problem?

Thanks,

Ethan, Louisville, KY

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Re: Kustom Commander fizzes out after 30 minutes of play (why?) [message #14131 is a reply to message #14121]

Wed, 28 July 2010 05:56

stevem
Messages: 4736
Registered: June 2004
Location: NY

Senior Member

If in the process of fizzing out does the pilot lamp goes out also? If so than the cutting out is caused by the thermosatic circuit breaker going open.

This could be due to a bias problem in the output stage running the output transistors too hot, or it could just be the T sat itself failing when it gets up to a certain temperature due to age.
The circuit breaker is all of a 4 dollar item and very easy to replace.
If I recall right they are rated to open at 186 degrees, so the rear lower chassie of the amp would feel quite hot to the touch for a good breaker to do its thing and go open.

If the lamp stays on when the sound cuts out then it could be due to the moldex connectors used in these making a intermitant connection( like the connector going from the preamp circuit board to the output stage driver board), or it could be a bad solder joint, or a failing semiconductor.

If you go to Radio Shack you can pick up a can of frezze spray and use it to cool down sections of the amp and narrow down where the problem lies.

[Updated on: Wed, 28 July 2010 05:57]

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Re: Kustom Commander fizzes out after 30 minutes of play (why?) [message #14132 is a reply to message #14131]

Wed, 28 July 2010 11:53

ethan
Messages: 5
Registered: July 2010

Junior Member

Thank you for all the info.
unfortunately, the light has never come on since i have ownede this machine...
but i will go get one of those cans because i am sure that it is an over heating problem...

thanks again.

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Re: Kustom Commander fizzes out after 30 minutes of play (why?) [message #14133 is a reply to message #14121]

Wed, 28 July 2010 13:05

stevem
Messages: 4736
Registered: June 2004
Location: NY

Senior Member

A replacement mini bulb that screws in behind the blue len on your on/off switch is a GE 335 and can ordered from Mouser supply.
If you do a search on this site you will find many postings covering replacing the bulb.

Note that inside the amp on the mounting bar that the output transistors are mounted on ( along with that circuit breaker) you will find a sensor diode mounted in a clip, if a lead of this diode is broken off, or is popped out of the clip the amp will over heat.

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Re: Kustom Commander fizzes out after 30 minutes of play (why?) [message #14134 is a reply to message #14133]

Wed, 28 July 2010 13:22

ethan
Messages: 5
Registered: July 2010

Junior Member

Thank you very much!

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Re: Kustom Commander fizzes out after 30 minutes of play (why?) [message #14142 is a reply to message #14133]

Thu, 29 July 2010 07:16

pleat
Messages: 1452
Registered: June 2004
Location: Belding, Mi

Senior Member

Just a note on the light bulb, on the SS series, charger, commander, sidewinder, challenger, and Hustler amps, the square blue lens cover is not the on/off power switch. Those amps the power switch is on the back panel. Replacing the bulb on the SS series amps is a lot easier than the kustom amps that used the on/off square blue power and polarity switches.
With the amp out of the chassis, I remove all the screws that hold the front panel to the chassis, and tilt it forward to expose the two screws that hold the light assembly, remove the screws, and the blue lens can be pulled off to expose the bulb. unscrew the bulb and replace it.
pleat

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Re: Kustom Commander fizzes out after 30 minutes of play (why?) [message #14557 is a reply to message #14142]

Mon, 18 October 2010 11:47

ethan
Messages: 5
Registered: July 2010

Junior Member

Hey there,

so i had a guy figure out that the part needed is UC2854N, which is cross numbered with 81554 motorola hybrid transistor(?). would you know anywhere to find such a piece?

Thanks for all your help

ethan

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