sansuibutch
Super Member
The right channel sounds very distorted. The volume is there but the more I turn it up the more it distorts. Is there any potential or common problems with these that would cause that?
Hi,
Let the expert come in,refer the reviews for this amplifier here,its a great amplifier.
http://www.hifiengine.com/manual_library/sansui/ba-2000.shtml
sansuibutch,
Where are you located?
Do you have an oscilloscope?
You have a PM.I am in rochester ny. No I do not yet own a oscilloscope.
Are you talking about board f2630. The white wire from the switch and the red from the main fuse holder..?Have you tried reversing the red and whit input wires to the amp to see if the issue changes sides? Also swap the speaker wires left to right to eliminate and speaker issues. Offset will move around a little bit depending on amp temperature.
-Lee
Are you talking about board f2630. The white wire from the switch and the red from the main fuse holder..?
With heavy distortion on one side I would think you have either a bad 68 ohm, or 8.2 ohm, 470 ohm, or .33 ohm resistors, or an open output or two, or possibly an open or shorted transistor on the driver board. You should be able to check all of these with you ohm meter in circuit. Just make sure the power is off. Resistors are pretty straightforward, but you can compare to the other side to verify the reading is good.
You need to isolate to see what side is bad (on the circuit board.) To do this, with the unit on, touch pin 1 and then pin 2 with your finger when the unit is on. You should hear a hum. Don't worry, there shouldn't be any voltage on those pins, but you can check them for DC volts with a volt meter first.
Now that you identified the side, shut power and remove plug from the wall.
Using an ohm meter on RX1 scale or as low a scale as you have, and check B to E, then B to C, then E to C. Jot down the readings. Then reverse the leads and do these tests all over again. Do this for all of the outputs , and for all of the transistors on the bad side of the driver board. Next to the reading for the questionable side transistors, take reading of the transistors on the good side. Put all of the reading together, and repost here, and we may be able to point out problem readings.
With heavy distortion on one side I would think you have either a bad 68 ohm, or 8.2 ohm, 470 ohm, or .33 ohm resistors, or an open output or two, or possibly an open or shorted transistor on the driver board. You should be able to check all of these with you ohm meter in circuit. Just make sure the power is off. Resistors are pretty straightforward, but you can compare to the other side to verify the reading is good.
You need to isolate to see what side is bad (on the circuit board.) To do this, with the unit on, touch pin 1 and then pin 2 with your finger when the unit is on. You should hear a hum. Don't worry, there shouldn't be any voltage on those pins, but you can check them for DC volts with a volt meter first.
Now that you identified the side, shut power and remove plug from the wall.
Using an ohm meter on RX1 scale or as low a scale as you have, and check B to E, then B to C, then E to C. Jot down the readings. Then reverse the leads and do these tests all over again. Do this for all of the outputs , and for all of the transistors on the bad side of the driver board. Next to the reading for the questionable side transistors, take reading of the transistors on the good side. Put all of the reading together, and repost here, and we may be able to point out problem readings.
The reading from B to E and B to C should be the same.
I should have asked you what type of meter you had.
If it is an old analog with the Needle Meter (the best for checking transistors), put it on RX1 scale and for PNP transistor, put the pos lead on the emitter, and neg lead on Base. It should read around 5 ohms. then move the pos lead to the collector and this should also read 5 ohms (usually mid scale reading). Reverse the leads putting neg emitter and pos on base and you should get no needle deflection (infinite ohms) same with pos on base, and neg on Collector. pos to emitter and neg to collector should be no deflection (infinite ohms). Neg to emitter, and pos to collector should be no deflection as well. If any reading show "0" ohms, or full deflection, the transistor is shorted.
If you are using a digital meter it is a bit different. You need to put the meter on the diode function, and measure the same way as above. The big difference is that in forward conduction for B to E and B to C, you will get a reading like 500 to 900, and no reading when you reverse it. No reading E to C forward or reverse. Your digital meter may also give an audible beep when in forward conduction. If you get a reading of 0, the transistor is probably shorted.
Hope this helps. I have a really old Triplett analog meter that I use, and assume everybody has one.