Hi, I have some strange problem with my Alesis amplifier. One day I want to power the amplifier like every other day but it was completely dead, I opened it and checked the capacitors on PSU and found out that two big ones 63V 10000uF were strange but when I measure them they were fine. I decided to replaced them anyway with nippons because that Suscon is junk, I also replaced two 25V 220uF and one 35V 1000uF in that PSU because their capacitance was low under that 10% drop tolerance. After replacement amplifier turned On but signal from my sound card was not getting in amplifier, there was no sound and no bars were jumping on display on amplifier. Anyone have idea why and what to do ?
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Alesis RA500 Amplifier
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Re: Alesis RA500 Amplifier
Originally posted by charis View PostHi.
Does the relay kick in?
If no check the voltages.
Maybe the lights go off because goes to protection mode.
Also check the 2 preamp pcb voltages (and the potentiometer) after that go for the output mosfets check.
Yellow lights appear when I turn it on but that's normal, amplifier did that when it was working normally it's like his initialization or something when you power it up.
I will check that mosfets and other voltages and let you know more when I do that.
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Re: Alesis RA500 Amplifier
Ok very simple.
After the transformer and brige rectifier the power goes to TA7317 who works as over curent ,voltage,speaker terminal short detector.The use about 50v.Pin 6 is the relay drive output pin 8 the muting pin1 current detection Pin2 voltage detection.The vcc for the chip should be about 50v on Pin9 -50v on pin5.
To open the relay Pin 6 they send 5v square pulse with 3ms time period.
When the relay close feed j7 and j8 terminals(where are also +15 -15v) and the signal from C1815 who is NPN transistor for muting and conect to pin 7 who is the part to the discharge circuit and have a diode protection D403.
Also the relay have on the second side 2 caps c116 c216 after 2 same 4.7 resistors r161 r162 2watt.
So check Vcc check pulse on pin 6 check Vee -50v.If all ok go to relay check voltages and also the c116 c216 and r161 r162 .
Also the chip monitor the voltage and curent who goes to j4 and j6 terminals(you find there also +15 -15v)Last edited by charis; 04-03-2016, 05:37 PM.
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Re: Alesis RA500 Amplifier
So go to the schematic that rhomanski provided and go to page 14 find the TA3717p you will notice the marking U1, that is the chip number on the board. Pin1 usually has a indented circle on it. You can also google the pin out of TA3717P or google that number for the data sheet. That should start you off.
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Re: Alesis RA500 Amplifier
https://www.badcaps.net/forum/attach...0&d=1459801803
Where is J1 Female connector for the +/- 15V power supply for Op Amp? Unless you removed it to take the pictures, otherwise check and see if you do have +/- supplies.Last edited by budm; 04-05-2016, 10:50 AM.Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956
Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999
Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl
Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/
TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809
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Re: Alesis RA500 Amplifier
Originally posted by budm View Posthttps://www.badcaps.net/forum/attach...0&d=1459801803
Where is J1 Female connector for the +/- 15V power supply for Op Amp? Unless you removed it to take the pictures, otherwise check and see if you do have +/- supplies.
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Re: Alesis RA500 Amplifier
Originally posted by Thermaltake View PostLooks like relay is dead, need to replace it and it won't be that dong woo junk again for sure and see if anything else is dead.Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956
Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999
Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl
Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/
TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809
Comment
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Re: Alesis RA500 Amplifier
Thanks for the follow-up.Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956
Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999
Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl
Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/
TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809
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