h¦¦h studio 50 [message #26954] |
Mon, 20 December 2004 12:54 ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
mat
Messages: 6 Registered: May 2009
|
Esquire |
|
|
hi i have a lovely hh amp which i adore but the other day it stopped working!!!!!! When i turn it on the speaker moves forward with a rather loud pop and stays forward! but thats it! nothing else i can do basic electronics but i just dont know where to start any ideas? any help would be much appreciated! thanks Matt
|
|
|
Re: h¦¦h studio 50 [message #26955 is a reply to message #26954] |
Mon, 20 December 2004 16:51 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
hitsware
Messages: 51 Registered: May 2009
|
Baron |
|
|
>the speaker moves forward with a rather loud pop and stays forward Probably a blown (shorted) output xsistor, (the output is directly connected to 1 of the rails via the short). A start would be to test the xsistors, of if readily available just replace them. Put a lightbulb in series with one side of the AC mains in to limit the current in case something else is also screwed up. (this will prevent blowing up the new xsistors).............
|
|
|
|
|
OOOPS it just went bang! [message #26970 is a reply to message #26959] |
Thu, 06 January 2005 11:50 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
mat
Messages: 6 Registered: May 2009
|
Esquire |
|
|
i was trying to check if one of the transistors had blown using a multimeter when BANG one of the big capacitors (capacitor devision 4700uF) blew? would this be the reason for my prevouse fault or is this going to be due to something else ? please help i want my amp back!!! thanks Matt
|
|
|
Re: OOOPS it just went bang! [message #26971 is a reply to message #26970] |
Fri, 07 January 2005 01:29 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
![](http://audioroundtable.com/forum/images/custom_avatars/5.gif) |
Wayne Parham
Messages: 18757 Registered: January 2001
|
Illuminati (33rd Degree) |
|
|
When electrolytics fail, it is usually because a voltage was applied that was either higher than the rated value of the capacitor or of opposite polarity it was made for. Large value capacitors are used in the power supply, so you might find that transistor(s) or diode(s) were already blown and this took out the capacitor. Possible reasons include shorted rectifier diode(s) and open output transistor(s) allowing the power supply voltage to rise past the voltage limit of the capacitor. What I thinmk you might want to do is to remove the transistors and diodes and check them out of circuit. If you have a schematic, it will help you find the parts that are most likely to have failed. But even without a schematic, you can check the transistors and diodes. Be sure to remove them from the circuit when testing.
|
|
|
|
Re: OOOPS it just went bang! [message #26973 is a reply to message #26972] |
Fri, 07 January 2005 01:49 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
![](http://audioroundtable.com/forum/images/custom_avatars/5.gif) |
Wayne Parham
Messages: 18757 Registered: January 2001
|
Illuminati (33rd Degree) |
|
|
You are looking for continuity on PN junctions when forward biased and open circuit when reversed biased. Every junction should show this reading. So here's how you check it. Connect your meter with (+) to a "P" junction and (-) to an "N" junction, and it should show continuity. This is forward biasing the junction. The reading will usually be from 5-50 ohms, depending on the transistor and the battery in the meter. Reverse the leads, (+) to "N" junction and (-) to "P" junction and the meter should read open. This is a reverse-biased connection. Then connect from collector to emitter and test forward-bias continuity. If an NPN transustor, the collector is positive and the emitter negative to forward-bias and you should have continuity. PNP transistors are forward-biased with the collector negative and the emitter positive. Reverse bias the collector to emitter and it should show open.
|
|
|
|
|