Here I send some picture of the poor amp. I show the board after mounting components , the connection to heatsink , the all together view , and my trial to disconnect the Vss pins from the IC2 .
this is the Ist part , the IInd follows
this is the Ist part , the IInd follows
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Second part of the message
Ok , this is my last trial , then I think I try to remove all and mount on another board. I suspect I did a really dum operation , but everything is dum once you discover it , not before.
bye
Stefano
Ok , this is my last trial , then I think I try to remove all and mount on another board. I suspect I did a really dum operation , but everything is dum once you discover it , not before.
bye
Stefano
Attachments
I don't have any LM3886 board to chek. Anyhow i'll try to see with tester.
PS: do you think that missing the bypass capacitor on pin 13 during my test could cause an overcurrent ? For RF autooscillating I mean ?? SInce during my test , i tied up the VSS+ connected pins , and in this way , when i supply it , there is no capacitor conneted.
best regards
PS: do you think that missing the bypass capacitor on pin 13 during my test could cause an overcurrent ? For RF autooscillating I mean ?? SInce during my test , i tied up the VSS+ connected pins , and in this way , when i supply it , there is no capacitor conneted.
best regards
I have planted the parts on the stereo board. The sound is good on 8Ohm, although i suspect the power is lower than 100W. I think the IC's get quite hot at medium volume.
1. The power supply is symmetrical 2 x 26v. I have measured the voltages on the capacitors. I think something might not be in order.
C1,C7 - 15v;
C5, C9 - 26v;
C6, 10 - no voltage ?! ;
C8, C13 - 19v.
What other voltages should i measure in order to pinpoint the problem?
The terminals of the parts are long because i planted them for a test. I plan to use tantalum capacitors and better quality resistors. The terminals don't touch, although they might look like touching.
2. The radiator is L shape, SK610 from Fischer. PDF in the attachment
SK 610 50 AL FISCHER ELEKTRONIK - Heatsink: extruded SK610-50AL | TME - Electronic components
Dimensions: 50mm x 55mm x 31mm
Is it enough?
3. I did not have 1uF capacitorsfor input C11, C12. I put 220nF. How does this affect the sound or the performance?
1. The power supply is symmetrical 2 x 26v. I have measured the voltages on the capacitors. I think something might not be in order.
C1,C7 - 15v;
C5, C9 - 26v;
C6, 10 - no voltage ?! ;
C8, C13 - 19v.
What other voltages should i measure in order to pinpoint the problem?
The terminals of the parts are long because i planted them for a test. I plan to use tantalum capacitors and better quality resistors. The terminals don't touch, although they might look like touching.
2. The radiator is L shape, SK610 from Fischer. PDF in the attachment
SK 610 50 AL FISCHER ELEKTRONIK - Heatsink: extruded SK610-50AL | TME - Electronic components
Dimensions: 50mm x 55mm x 31mm
Is it enough?
3. I did not have 1uF capacitorsfor input C11, C12. I put 220nF. How does this affect the sound or the performance?
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SK610.pdf38.9 KB · Views: 44
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tda7293.pdf391.9 KB · Views: 54
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338676.jpg27.4 KB · Views: 28
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prime_presentation_pres_0003.jpg19.4 KB · Views: 21
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prime_presentation_pres_0004.jpg19.9 KB · Views: 23
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IMG_20190816_193036.jpg174.7 KB · Views: 27
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IMG_20190816_193234.jpg539.9 KB · Views: 35
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61fNbLUTAGL._SL1024_.jpg78.1 KB · Views: 40
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amp002.jpg63.5 KB · Views: 51
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