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Re: Kustom 100 blowing fuse [message #27277 is a reply to message #27276]

Tue, 23 April 2019 18:00

JDinPA17603
Messages: 72
Registered: May 2018
Location: Lancaster, PA

Member

timetraveler I am a little confused so I am offering this to you for reference. I know how confusing and frustrating this can be.

Driver transistors
Q4 is a NPN 40409 equivalent is NTE128
Q5 is a PNP 40410 equivalent is NTE129
They can be had as a matched pair by ordering NTE129MCP
NOTE: the correct transistor must be installed in the correct position
Both of the driver transistors must have a heat sink installed on it and care must be taken not to short the heat sink to any nearby components.

Protection circuit
Q6 is a NPN 2N3567 equivalent is a 2N3567 or a NTE123
Q7 is a PNP 2N3638 equivalent is a 2N3638 or a NTE129
Note as with the driver transistors these must be installed in the correct position.

Output circuit
Q8 and Q9 are NPN 36892 equivalent is 2N3055 or NTE130
I recommend a matched pair - order NTE130MP
THESE ARE INSTALLED with a mica washer between the transistor and the chassis with heat sink grease applied to both sides of the mica film washer ... between chassis and washer and between washer and transistor.
They also use nylon washers and bushings to isolate the case from the chassis.

Diodes and electrolytic capacitors must be installed in the proper orientation.
Resistors should be as close as possible to the correct values.
Check for accidental shorts between traces on the board.
With the 1N3754 make sure that the leads are not broken or shorted to the clip or each other And insure that the diode is securely fastened in the clip.
All voltage measurements are with no load (speakers disconnected), no signal input (all plugs unplugged from the inputs) and all controls full up.

Since you are having an issue with parts continuing to blow, as others have suggested, use a light bulb limiter (100 watt incandescent lightbulb) wired in series with the power cord) and decrease the amperage on the fuse until you get this straightened out.

Good luck with the amp.

John

Old Us Navy Vietnam Vet
Playing for my own enjoyment and irritation of the neighbors.

[Updated on: Tue, 23 April 2019 18:28]

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[Message index]

		Kustom 100 blowing fuse By: imsteinrecording on Tue, 08 January 2013 05:45
		Re: Kustom 100 blowing fuse By: stevem on Tue, 08 January 2013 10:39
		Re: Kustom 100 blowing fuse By: imsteinrecording on Tue, 08 January 2013 16:16
		Re: Kustom 100 blowing fuse By: timetraveler on Wed, 10 April 2019 17:58
		Re: Kustom 100 blowing fuse By: chicagobill on Tue, 08 January 2013 12:03
		Re: Kustom 100 blowing fuse By: imsteinrecording on Tue, 08 January 2013 16:17
		Re: Kustom 100 blowing fuse By: chicagobill on Thu, 11 April 2019 15:15
		Re: Kustom 100 blowing fuse By: timetraveler on Fri, 12 April 2019 09:55
		Re: Kustom 100 blowing fuse By: stevem on Fri, 12 April 2019 06:10
		Re: Kustom 100 blowing fuse By: stevem on Fri, 12 April 2019 12:32
		Re: Kustom 100 blowing fuse By: chicagobill on Fri, 12 April 2019 13:31
		Re: Kustom 100 blowing fuse By: JDinPA17603 on Fri, 12 April 2019 21:02
		Re: Kustom 100 blowing fuse By: timetraveler on Sat, 13 April 2019 12:08
		Re: Kustom 100 blowing fuse By: stevem on Sat, 13 April 2019 06:24
		Re: Kustom 100 blowing fuse By: timetraveler on Sat, 13 April 2019 14:07
		Re: Kustom 100 blowing fuse By: timetraveler on Sat, 13 April 2019 14:14
		Re: Kustom 100 blowing fuse By: stevem on Sun, 14 April 2019 06:13
		Re: Kustom 100 blowing fuse By: JDinPA17603 on Sun, 14 April 2019 11:01
		Re: Kustom 100 blowing fuse By: timetraveler on Sun, 14 April 2019 19:05
		Re: Kustom 100 blowing fuse By: stevem on Mon, 15 April 2019 06:12
		Re: Kustom 100 blowing fuse By: chicagobill on Mon, 15 April 2019 12:23
		Re: Kustom 100 blowing fuse By: timetraveler on Mon, 22 April 2019 17:02
		Re: Kustom 100 blowing fuse By: JDinPA17603 on Mon, 22 April 2019 19:12
		Re: Kustom 100 blowing fuse By: timetraveler on Tue, 23 April 2019 10:42
		Re: Kustom 100 blowing fuse By: JDinPA17603 on Tue, 23 April 2019 12:12
		Re: Kustom 100 blowing fuse By: stevem on Tue, 23 April 2019 12:13
		Re: Kustom 100 blowing fuse By: chicagobill on Tue, 23 April 2019 12:30
		Re: Kustom 100 blowing fuse By: stevem on Tue, 23 April 2019 12:35
		Re: Kustom 100 blowing fuse By: timetraveler on Tue, 23 April 2019 13:19
		Re: Kustom 100 blowing fuse By: JDinPA17603 on Tue, 23 April 2019 18:00
		Re: Kustom 100 blowing fuse By: timetraveler on Wed, 24 April 2019 08:33
		Re: Kustom 100 blowing fuse By: chicagobill on Thu, 25 April 2019 13:20
		Re: Kustom 100 blowing fuse By: timetraveler on Thu, 09 May 2019 14:19
		Re: Kustom 100 blowing fuse By: JDinPA17603 on Thu, 09 May 2019 16:33
		Re: Kustom 100 blowing fuse By: timetraveler on Fri, 17 May 2019 11:43
		Re: Kustom 100 blowing fuse By: timetraveler on Sun, 19 May 2019 08:48
		Re: Kustom 100 blowing fuse By: timetraveler on Tue, 04 June 2019 13:31
		Re: Kustom 100 blowing fuse By: timetraveler on Tue, 04 June 2019 13:34
		Re: Kustom 100 blowing fuse By: stevem on Wed, 24 April 2019 07:40
		Re: Kustom 100 blowing fuse By: stevem on Fri, 17 May 2019 12:21
		Re: Kustom 100 blowing fuse By: timetraveler on Fri, 17 May 2019 12:51
		Re: Kustom 100 blowing fuse By: stevem on Fri, 17 May 2019 13:40
		Re: Kustom 100 blowing fuse By: chicagobill on Sun, 19 May 2019 15:13
		Re: Kustom 100 blowing fuse By: stevem on Mon, 27 May 2019 05:45
		Re: Kustom 100 blowing fuse By: chicagobill on Tue, 04 June 2019 23:28
		Re: Kustom 100 blowing fuse By: chicagobill on Wed, 05 June 2019 12:26
		Re: Kustom 100 blowing fuse By: timetraveler on Wed, 05 June 2019 20:27
		Re: Kustom 100 blowing fuse By: stevem on Wed, 05 June 2019 12:35
		Re: Kustom 100 blowing fuse By: timetraveler on Wed, 05 June 2019 20:19
		Re: Kustom 100 blowing fuse By: chicagobill on Wed, 05 June 2019 23:45
		Re: Kustom 100 blowing fuse By: chicagobill on Thu, 06 June 2019 01:36
		Re: Kustom 100 blowing fuse By: timetraveler on Thu, 06 June 2019 12:08
		Re: Kustom 100 blowing fuse By: stevem on Thu, 06 June 2019 12:25
		Re: Kustom 100 blowing fuse By: timetraveler on Thu, 06 June 2019 12:53
		Re: Kustom 100 blowing fuse By: chicagobill on Thu, 06 June 2019 15:34
		Re: Kustom 100 blowing fuse By: stevem on Fri, 07 June 2019 06:06
		Re: Kustom 100 blowing fuse By: timetraveler on Fri, 07 June 2019 12:17
		Re: Kustom 100 blowing fuse By: chicagobill on Fri, 07 June 2019 15:28
		Re: Kustom 100 blowing fuse By: timetraveler on Sat, 08 June 2019 09:24
		Re: Kustom 100 blowing fuse By: stevem on Sat, 08 June 2019 05:30
		Re: Kustom 100 blowing fuse By: chicagobill on Sat, 08 June 2019 12:01
		Re: Kustom 100 blowing fuse By: timetraveler on Mon, 10 June 2019 15:16
		Re: Kustom 100 blowing fuse By: chicagobill on Mon, 10 June 2019 19:47
		Re: Kustom 100 blowing fuse By: timetraveler on Wed, 12 June 2019 08:51
		Re: Kustom 100 blowing fuse By: stevem on Wed, 12 June 2019 12:07
		Re: Kustom 100 blowing fuse By: chicagobill on Wed, 12 June 2019 12:09
		Re: Kustom 100 blowing fuse By: timetraveler on Wed, 12 June 2019 21:24

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