Power supply https://www.amazon.com/gp/product/B08HYK2ZW3/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
I have been trying old working outputs IRF640N.
I just fitted three brand new IRF9640N on the high side and two old IRF640N on the low side for all banks of the output. When i power the amp up the three IRF9640N on the high side are excessively hot on both high side banks..
I have been trying old working outputs IRF640N.
I just fitted three brand new IRF9640N on the high side and two old IRF640N on the low side for all banks of the output. When i power the amp up the three IRF9640N on the high side are excessively hot on both high side banks..
I do not have a singal generator, only a rca from pc
Heres the voltages on with remote turn on for driver transistor bd139/140
PS set at 12.79v
remote on sags to 8.2v
bd139.
leg1 - 3.9v, leg 2: 8.7v, leg3: 4.8v
bd140
leg 1 - 3.8v, leg 2: 0v, leg 3: 4.8v
I am getting 3.55volt at the gate of the PS FET and the drive waves on the drain and gate looks normal
Here is some output FETs in the board and all the wave forms
Heres the voltages on with remote turn on for driver transistor bd139/140
PS set at 12.79v
remote on sags to 8.2v
bd139.
leg1 - 3.9v, leg 2: 8.7v, leg3: 4.8v
bd140
leg 1 - 3.8v, leg 2: 0v, leg 3: 4.8v
I am getting 3.55volt at the gate of the PS FET and the drive waves on the drain and gate looks normal
Here is some output FETs in the board and all the wave forms
Attachments
I have popped all the output FETs out. When measuring across collector, i shorted a transistor when measuring collector to collector.
When i powered the board back up, D8 or D10 when up in smoke. If these are one way diodes, i get reading on both ends of D1 and D8.
MultiMeter diode setting @ 0.67 and 1.9 for D1 & D8.
While D9 & D10 read infinite and 0.67
Powered up board and the D1 side warms up quite a bit, while the D8 side stays stone cold. Reading between source and gate are nonexistent now, so no Drive waves
High side gates' resistors now read lower than 20K ~ 19.6 instead. Prior was at 20k
I would like to pull board out and do a rebuild. Is there a place I can find reference to the SMDs I would most likely need to replace?
Q7, 11, 19 and 22
D9,D1,D8,D10
Q4,5,8,10,12,6,916,18,21,23 - i will try to google codes on these
I actually shorted the transistor before i pulled the FETs out, but was getting drive ways anyways - post power cycle
Only when the FETs were out did the diode smoke up.
Rechecked the Power supply FETs and the drain and gate waves look very much perfect.
When i powered the board back up, D8 or D10 when up in smoke. If these are one way diodes, i get reading on both ends of D1 and D8.
MultiMeter diode setting @ 0.67 and 1.9 for D1 & D8.
While D9 & D10 read infinite and 0.67
Powered up board and the D1 side warms up quite a bit, while the D8 side stays stone cold. Reading between source and gate are nonexistent now, so no Drive waves
High side gates' resistors now read lower than 20K ~ 19.6 instead. Prior was at 20k
I would like to pull board out and do a rebuild. Is there a place I can find reference to the SMDs I would most likely need to replace?
Q7, 11, 19 and 22
D9,D1,D8,D10
Q4,5,8,10,12,6,916,18,21,23 - i will try to google codes on these
I actually shorted the transistor before i pulled the FETs out, but was getting drive ways anyways - post power cycle
Only when the FETs were out did the diode smoke up.
Rechecked the Power supply FETs and the drain and gate waves look very much perfect.
Attachments
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Transistor marked 2A - 2n3906,_mmbt3906,_pzt3906_fairchild
Transistor marked 1A - 2n3904,_mmbt3904,_pzt3904_fairchild
1D and 2D MMBTA42 and MMBTA92
Transistor marked DK - 2sc4672
Transistor marked AG - 2sa1797
The diodes along the top of the board are 1N4148 types.
Also check all of the 470 ohm resistors.
The following is generally good without being overwhelming.
http://www.marsport.org.uk/smd/mainframe.htm
It appears that there may be some via material on the pins (resolution insufficient to see clearly). If it is, buy and use ChipQuik when removing driver boards.
Transistor marked 1A - 2n3904,_mmbt3904,_pzt3904_fairchild
1D and 2D MMBTA42 and MMBTA92
Transistor marked DK - 2sc4672
Transistor marked AG - 2sa1797
The diodes along the top of the board are 1N4148 types.
Also check all of the 470 ohm resistors.
The following is generally good without being overwhelming.
http://www.marsport.org.uk/smd/mainframe.htm
It appears that there may be some via material on the pins (resolution insufficient to see clearly). If it is, buy and use ChipQuik when removing driver boards.
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