LME49830 board wiring connections

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From what little tech information I am still faced with, I did read where MOSFETS need a small level of AC voltage in addition to the DC rail voltage to function correctly. Is this correct and where does this additional AC voltage need to be applied?

Incorrect.
Remove your 18VAC supply.

I saw on a similar LME49810 board with the same MOSFET design, connection terminals being almost the same, except for the terminal labeled GRD1 on my board (also referred to as GRD_A on the schematic shown earlier in this thread), was labeled as AC. So as you see on my sketch I have 18 AC volts connected to my board terminal labeled GRD1. The board does power up and seems stable with some heat being generated in the heat sink. Or am I way wrong here and this additional AC voltage is needed for the speaker protection circuit? Or something else?

Absolutely no idea.
You need the correct schematic first. It is quite difficult to guess what goes where and what is needed, without it.

My wild guess is, check the grounding as Mark suggested.
 
I'll remove the caps across the electrolytics as you suggested. What about the 4 small caps across the rectifier lugs? Are the rectifier caps needed to lessen ripple? I have 5 watt 2k ohm bleeder resistors across the electrolytics. Are these OK. Only one is visible in my bottom shot pic. The other is on the top side of the board. Is there going to be a grounding problem between the 2 different transformers? Another sketch attached to help me understand and further clarify what I am working with here.
Thanks Dennis
An externally hosted image should be here but it was not working when we last tested it.
 
Sorry about goofing my posting up again. I did not get my edit done quickly enough. So here is my last post again.



I'll remove the caps across the electrolytics as you suggested. What about the 4 small caps across the rectifier lugs? Are the rectifier caps needed to lessen ripple? I'll disconnect the 18 volt voltage supply. I have 5 watt 2k ohm bleeder resistors across the electrolytics. Are these OK. Only one is visible in my bottom shot pic. The other is on the top side of the board. Is there going to be a grounding problem between the 2 different transformers? I can't seem to hear any clicking coming from the protection circuit relay. I think there is a reset button present on top the relay which does not seem to be popped. Another sketch is attached (shown in last post) to help me understand and further clarify what I am working with here.

I have not been able to get specific board information from the outfit in China who I bought the boards from or anywhere else online. Only the generic LME49810 schematic which is posted earlier in this thread. Short of sending the boards back for a refund, which is to late to do anymore, you forum members best guess me be my only hope. It seems I am the only person out there who has bought and is using this specific LME49830 board. I do and will appreciate all the continued help.
Thanks Dennis
 
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Probably better if you try to get the amp working with a simple dual rail (single transformer) supply first.
Then add the second pair of rails for the input stage when you get the sound from the simple PSU.

You could also try to get a nice photo of your amplifier board from both sides, so people here can see what you have on the boards, and what goes where (by following the tracks).

Here is a nice simple PSU. http://www.diyaudio.com/forums/chip-amps/265751-lm3886-grounding-am-i-doing-right-5.html#post4144189
 
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Mark
So will the junction of the orange and red Avel secondary wires (center tap) be connected to the central white wire on the PSU cap arrays . See new attached sketch. Looking ahead a step further, how will the ground potentials of the center tap in regard to chassis earth, likewise the black wire from the Crown, and or between the transformers them selves play out? I see AC voltage readings of 13 volts (red and orange wire to chassis) from the Avel and 44 AC volts from the Crown (black wire to chassis.
Dennis
An externally hosted image should be here but it was not working when we last tested it.
 
I see now that the output transistor location on the PC are also mislabeled also. I was hoping these boards would offer quality performance. As you say if the board components are legitimate it should work well. I will keep my fingers crossed. Photo of the actual board below.

To make sure I understand correctly, if I wire only my PS rail outputs to terminals -VCC and +VCC accordingly and ground, not using the +V and -V terminals at all, the board will operate. Though better performance can be achieved connecting the -V and +v in parallel with my same -VCC and +VCC rail outputs . And if I would choose to provide a second PS board and connect -V and +V board terminals to it, even higher quality performance will be attained.
Dennis
An externally hosted image should be here but it was not working when we last tested it.

This board overlay in your photo shows 2SA and 2SA bipolar - 2SA1943 outputs and 2SA1802 and 2SC5171 drivers. The complement for 2SA1943 not visible in the photo would be 2SC5200. These component designations are consistent with the circuit in your original post which depicts a bipolar output stage. If 2SK1530 and 2SJ201 came with the board then you would have cause to worry about having been correctly supplied.
 
This is why I dislike centre tap transformers for audio. Where do you place the 0 V.
Here is the centre tap way to wire it. Check if the rectifier is good for 100V or more.
The chassis to GND connection depends on the layout of the amp boards, but in your build it can be connected to the output of the PSU board.

Post some photo's before testing.
 

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This is why I dislike centre tap transformers for audio. Where do you place the 0 V.
Here is the centre tap way to wire it. Check if the rectifier is good for 100V or more.
The chassis to GND connection depends on the layout of the amp boards, but in your build it can be connected to the output of the PSU board.

Post some photo's before testing.

See also the link for more on 'how to' in full detail.

How to wire-up a Power Amplifier | hifisonix.com

If you have MOSFET's in a layout designed for bipolar transistors that would be a bigger problem. I am unfamiliar with the particular devices possibly used here - some power MOSFET's have an inbuilt protective zener diode to limit the voltage applied to the gate lead others include an external diode in the circuit for that job.
 
Thanks for all the input fellows! I am going to lay back and take a deep breath for a moment before proceeding further. I may give up on my home brew power supplies and purchase ready made boards. At least one. I have not spent a whole lot of money on the PSUs and will eventually use them for tinkering. I may be gun shy on looking for deals from Asia any more. I do intend to pester the company I bought the amp boards from to see if they will cough up more accurate board specific technical data and user information. In the meantime if any one stumbles upon pertinent board info please let me know.

Mjona, if you read this post, I removed an amp board from the heatsink and double checked the identification of the provided transistors. The chip amp is definitely marked as an LME49830. The output drivers are 2SK1530's and 2SJ201's. Does this fact render these boards useless?
Thanks again everyone.
Dennis
 
The LME49810 and LME49830 chips come in the same packaging. The lead outs are pretty much the same except for pin 1 which has no internal connection in the case of LME49830. In the LME49810 it connects to a warning LED and probably performs a limiting function.

The LME49830 has no use in the board sent to you and the same applies for the 2SK and 2SJ MOSFETs so if you wanted the MOSFET amplifier then you don't want to be unsoldering boards to transfer to the proper board and it will be better to start afresh - I think the supplier should be asked to provide new boards and the matching componentry including the circuit diagram.

I tried to locate the website for the kit manufacturer - the name on the board overlay - and drew a blank. I will keep my fingers crossed for you.

I would keep the boards you have until this issue is resolved. These could be a standby option - you could remove the MOSFET outputs and the LME49830 and replace these with the devices specified on the overlay. I am interested to see how you get on.
 
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