I see 2 groups of wires coming off of each transformer: one group of wires consists of 2 black wires, 1 red wire and 1 clear wire; the other group of wires is one black, one grey and one purple and they are a good bit smaller wire diameter.
The red and clear wires in the first group go to the bridge rectifiers and the black, grey and purple wires all go to one molex type connector on the power input boards for each channel.
The black wires in the first group appear to be ground wires.
The 4 big caps are underneath the bridge rectifier board and the power input boards.
Which ones do I pull or do I pull them all? Thinking I should pull the red and clear wires and the 2 molex connectors (black purple and grey)?
Thanks!
The red and clear wires in the first group go to the bridge rectifiers and the black, grey and purple wires all go to one molex type connector on the power input boards for each channel.
The black wires in the first group appear to be ground wires.
The 4 big caps are underneath the bridge rectifier board and the power input boards.
Which ones do I pull or do I pull them all? Thinking I should pull the red and clear wires and the 2 molex connectors (black purple and grey)?
Thanks!
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Look at the diagram in post #78. I think the plugs with the three wires will be the the group on the right of the diagram. So those can be pulled.
The other high current supply only needs the two input wires on each bridge pulling. The centre tap connection from the transformer can be left connected.
The other high current supply only needs the two input wires on each bridge pulling. The centre tap connection from the transformer can be left connected.
Yes, E501 and E601 are the 2 molex type plugs that are the blk, purple and grey wires.
What do you mean by "The centre tap connection from the transformer can be left connected."? I don't see a center connection. There are four connections on the bridge rectifier and 2 of them appear to be output going to the big caps (2 per channel, orange and red wires). These are the 2 (per channel) that I would leave plugged in since they appear to be output.
Thanks.
I'm guessing here (and I hate to guess) but is that the black wire????
The black wire coming from the transformer is the only one that doesn't go to the bridge rectifier and I was not going to pull it.
I was going to pull the red and clear wires - the only 2 wires going to the bridge rectifier from the transformer which agrees with your diagram.
The black wire coming from the transformer is the only one that doesn't go to the bridge rectifier and I was not going to pull it.
I was going to pull the red and clear wires - the only 2 wires going to the bridge rectifier from the transformer which agrees with your diagram.
OK, I think I have at least isolated the cause of the hum to the right channel.
By pulling only the wires noted above, this is what happens:
1. I started off isolating both transformers from any output by pulling all the wires noted and I got no hum.
2. Next, I connected the right channel only and I got the hum.
3. I then disconnected the right channel and connected only the left channel and got no hum.
One interesting thing to note: When only the right channel is connected (the channel that apparently causes the hum) I hear the speaker relay click but the green NORMAL led light on the front panel does not illuminate. When only the left channel is connected I hear the relay click and the green NORMAL led light is illuminated. This amp is not intended to run mono for each channel so I don't know if it should illuminate when either of the channels is powered or just the left so it may or may not be a clue.
So, where do I look now for the cause of this hum since it appears to be isolated to the right channel?
By pulling only the wires noted above, this is what happens:
1. I started off isolating both transformers from any output by pulling all the wires noted and I got no hum.
2. Next, I connected the right channel only and I got the hum.
3. I then disconnected the right channel and connected only the left channel and got no hum.
One interesting thing to note: When only the right channel is connected (the channel that apparently causes the hum) I hear the speaker relay click but the green NORMAL led light on the front panel does not illuminate. When only the left channel is connected I hear the relay click and the green NORMAL led light is illuminated. This amp is not intended to run mono for each channel so I don't know if it should illuminate when either of the channels is powered or just the left so it may or may not be a clue.
So, where do I look now for the cause of this hum since it appears to be isolated to the right channel?
If the transformers are fired up one at a time (with the secondaries isolated) and only one makes a noise then that points to that particular transformer being noisy.
If you follow the LED circuits voltage rail back to the power supply it looks to come from the left channel circuitry so that is why it does not work when the right only is powered up.
If you follow the LED circuits voltage rail back to the power supply it looks to come from the left channel circuitry so that is why it does not work when the right only is powered up.
Not sure if I explained what I did in the last step well enough: I get no hum when power is turned on to both transformers but the output wires from the transformer are disconnected - nothing is connected downstream.
The right channel only hums when its outputs are connected (to the bridge rectifier and the power output board). So, essentially it only hums when this small load is placed on it. Just running at power with it disconnected it doesn't hum at all.
The left transformer doesn't hum under any circumstance.
Are the "secondaries" that you are referring to the molex connection E501 (blk/purple/grey wires)?
Its difficult without having one in front of me 🙂 Looking at pictures on the web and I can only see what looks like a single toroid in these.
Like these:
So this might sound a silly question but are there two separate transformers in yours. As in physically separate. Two toroids? Are they stacked one on another?
I can't really see anything fault wise in the amp that would make a transformer hum.
Like these:
So this might sound a silly question but are there two separate transformers in yours. As in physically separate. Two toroids? Are they stacked one on another?
I can't really see anything fault wise in the amp that would make a transformer hum.
Yes - there are 2 separate toroids stacked one on top of the other. They appear to be completely independent of one another as I can disconnect each one by itself. That picture that you posted appears to be a 2200II just like both of mine but the toroids are enclosed on that one (possibly a later serial number).
Pic below shows layout.
The power comes in to the terminal block and then 2 separate feeds go to the toroid transformers (left channel toroid is on top, right channel is on bottom). From the transformers power then goes to the bridge rectifiers and the power output boards where the big power caps sit underneath (can't see in pic). Then there is one long narrow bias board that runs underneath as well (one per channel).
Since I am using this to power my center channel speaker, I may just wind up disconnecting the right side toroid at the terminal block and run just the left channel. The amp appears to be essentially 2 completely separate channels in one housing so I may try this next. I am getting to the point of exhaustion on troubleshooting this and if I can get one channel working that will be OK.
Pic below shows layout.
The power comes in to the terminal block and then 2 separate feeds go to the toroid transformers (left channel toroid is on top, right channel is on bottom). From the transformers power then goes to the bridge rectifiers and the power output boards where the big power caps sit underneath (can't see in pic). Then there is one long narrow bias board that runs underneath as well (one per channel).
Since I am using this to power my center channel speaker, I may just wind up disconnecting the right side toroid at the terminal block and run just the left channel. The amp appears to be essentially 2 completely separate channels in one housing so I may try this next. I am getting to the point of exhaustion on troubleshooting this and if I can get one channel working that will be OK.
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Thanks 🙂 so that makes a bit more sense.
Why not just try swapping them around if the leads will reach, the two molex plugs and the leads to the bridge and see if the same transformer still makes a noise.
Why not just try swapping them around if the leads will reach, the two molex plugs and the leads to the bridge and see if the same transformer still makes a noise.
I went ahead and disconnected the right channel entirely by removing the input wires to the toroid and powered it up with just the left channel operating. Powered up fine so I went ahead and hooked it up to an input source and a speaker and let it run for about an hour and it ran with no issues. Sounds fine.
So, I am going to put it back in my rack like this since I don't really need both channels to operate.
Thanks for all your help. I will try to post back if I ever have time to get back to troubleshooting it further.
So, I am going to put it back in my rack like this since I don't really need both channels to operate.
I may try that at some point but for now I am just going to run it as a single channel amp.
Thanks for all your help. I will try to post back if I ever have time to get back to troubleshooting it further.
lesseee,,,, 500W @ 240V is 115 Ohms. 15:1 change from hot to cold predicts a 7.7 Ohm cold resistance. 7.7r @ 12V is 18 Watts. Or 1/26.7th of design wattage at white-hot. Probably runs at like 1/3rd absolute temperature. I might not say "illuminate" but "dull red glow".
Those 'halogens' tend to "light" at lower voltages because they run so incredibly hot at design voltage. At 5% of rated voltage the halogen fill is more hindrance than help (no tungsten vapor to recapture; added convection cooling) but they still do better than we might think.
