Hifonics bxi 3000 question driver

[Achim1409]

I got this amp with burned power supply. Iam not sure with the markings of the driver transistors. Maybe someone can tell me the right name.

 

[Osvaldo de Banfield]

8A and DA seems to me. There are several web pages where to find SMD codes. They appears to be two complementary pairs. Are this the driver's of the output MOSFET's?

 

[twilliar]

https://www.mouser.com/datasheet/2/196/bcw61_bcx71-55820.pdf

Here is a quick link for hfE ratings. Those are BA and DA transistors.

 

[Perry Babin]

If you can't find exact replacements and this for the power supply, The 2SB1260 and the 2SD1898 should work.

The G1 could be several different part numbers. Most are NPN transistors. The MMBT5551 is probably the safest bet. I have no clue how it's being used in this circuit. If it checks good, I'd probably leave it as is.

Marking of electronic components, SMD Codes G1, G1**, G1***, G1-, G1-***, G11, G15N60, G1=**, G1=***, G1F, G1W, G1p, G1t. Datasheets BC847B, BFS20, DTB113ZK, EMG1, EUP7965-18VIR1, FMG1A, KST5551, MMBT5551, RT9161A-16PX, RT9166-33GVL, RT9166-33PVL, RT9715BGQW, SGB15N60, SGP15N60, SGW15N60, Si2351DS, TC1188-TECT, UMG1N.

 

[Achim1409]

For BA i found only BCX54... But for DA,, nothing what could be a transistor...

I think i will use Perrys advice and take 2SB1260 and 2SD1898

 

[Leolabs]

2SA1419S and 2SC3649S will also work just fine.I being using them in a burned board just like yours.

Note that double check everything before you put it back,especially those FETs and gate resistor too.

 

[Achim1409]

Still trouble with the ps. Changed the driver transistors. Mounted for test 4 fets. The current is high, gate resistors start smoke. Removed rectifiers, still the same. Can't take out the Trafos, because they are glued in. Removed the fets, put a capacitor. See pictures. I think it's still something with the driver card.

 

[Achim1409]

If I bend the board, the time from the amplitude is extended or longer. Solderings are all OK. Checked 5 times.. I expect a broken resistor on the board.

 

[Perry Babin]

The frequency is too high.

There may be another problem causing the falling side of the waveform to extend.

 

[Achim1409]

The cap for CT of the tl494 is broken.. Any suggestions which capacity it must have? The resistor has 22k

 

[Perry Babin]

Start with a 1000pf and see what that gives you for frequency. You want something between 25k and 30kHz at the FET gates.

Although it's not critical, if you have to order a replacement, use a capacitor with a temperature rating or X7R/C0G/NPO. The frequency will vary less with temperature change than with wider tolerance capacitors.

 

[Achim1409]

Mounted 1nf cap, amplitude looks OK, not perfect. Current draw is gone.. I think I can continue with audio part.