Guitar Amp blowing resistors

argonrepublic · 30th April 2009, 02:52 AM

This guitar amp is blowing resistors. I am kind of Thinking outputs are shorted. J162 Output transistors. I kind of thought they worked like diodes. I am getting current flow in both directions on 2 of 6 of them. Any body lead me to database for Datasheets? I need to convert shematic from PDF to upload.

pacificblue · 30th April 2009, 03:06 PM

http://www.datasheetcatalog.com/

You are right about the diode-like working. If you disconnect them and get conitinuity in both directions the transistors need to be replaced. Check the driver transistors as well. They often blow together with the output transistors.

You don't need to convert from pdf to upload as long as the file size remains within the limits.
If you have no possibility to make the pdf small enough, take a screenshot and upload that as jpg. How to take a screenshot? Push Ctrl + Print at the same time. Open a graphic viewer (e. g. Paint or IrfanViewer) and paste the screenshot in (Ctrl + V). Edit the picture as necessary and save it as jpg.
You can upload files up to 100k, I think. If they are bigger you can host (google picture hosting) them somewhere and post a link.

argonrepublic · 1st May 2009, 12:37 AM

Can't seem to copy and paste for now but the datasheet database is great. It'll keep me busy for a while. Thanks so much.

argonrepublic · 1st May 2009, 01:12 PM

Amp has 3 K1058s and 3 J162s for output. One of the J162s had an open resistor on its output. All six transistors are paralleled to speaker + except the one that was open. The leg of the resistor was open I am guessing that would cause other 5 to overworking causing the original problem or I wonder if I didn't disturb it myself

argonrepublic · 2nd May 2009, 12:13 AM

Should heater voltage be DC. Heater connections are mark - and + but I am seeing 13 VAC. I am wonder if rectifier is bad and that is causing problem.

30th April 2009, 02:52 AM	#1
argonrepublic diyAudio Member Join Date: Apr 2005 Location: Simcoe Ont	Guitar Amp blowing resistors This guitar amp is blowing resistors. I am kind of Thinking outputs are shorted. J162 Output transistors. I kind of thought they worked like diodes. I am getting current flow in both directions on 2 of 6 of them. Any body lead me to database for Datasheets? I need to convert shematic from PDF to upload.

30th April 2009, 03:06 PM	#2
pacificblue diyAudio Member Join Date: May 2008	http://www.datasheetcatalog.com/ You are right about the diode-like working. If you disconnect them and get conitinuity in both directions the transistors need to be replaced. Check the driver transistors as well. They often blow together with the output transistors. You don't need to convert from pdf to upload as long as the file size remains within the limits. If you have no possibility to make the pdf small enough, take a screenshot and upload that as jpg. How to take a screenshot? Push Ctrl + Print at the same time. Open a graphic viewer (e. g. Paint or IrfanViewer) and paste the screenshot in (Ctrl + V). Edit the picture as necessary and save it as jpg. You can upload files up to 100k, I think. If they are bigger you can host (google picture hosting) them somewhere and post a link. __________________ If you've always done it like that, then it's probably wrong. (Henry Ford)

1st May 2009, 12:37 AM	#3
argonrepublic diyAudio Member Join Date: Apr 2005 Location: Simcoe Ont	J162 Can't seem to copy and paste for now but the datasheet database is great. It'll keep me busy for a while. Thanks so much.

1st May 2009, 01:12 PM	#4
argonrepublic diyAudio Member Join Date: Apr 2005 Location: Simcoe Ont	Amp Amp has 3 K1058s and 3 J162s for output. One of the J162s had an open resistor on its output. All six transistors are paralleled to speaker + except the one that was open. The leg of the resistor was open I am guessing that would cause other 5 to overworking causing the original problem or I wonder if I didn't disturb it myself

2nd May 2009, 12:13 AM	#5
argonrepublic diyAudio Member Join Date: Apr 2005 Location: Simcoe Ont	Tube heater Should heater voltage be DC. Heater connections are mark - and + but I am seeing 13 VAC. I am wonder if rectifier is bad and that is causing problem.


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