HELP!!!!!!!!!! MY alpine MRV 1507 damage. any 1 can help me?? pls.

[Perry Babin]

Have the ones in your amp failed?

 

[jasyip5052]

yes. that y i cannot reply u so for
long time

 

[Perry Babin]

Did you check them out of the circuit. I've never seen these fail before.

 

[jasyip5052]

yes, i follow the diode checking method, i get a very low ohm for the left channel 1.

 

[Perry Babin]

If you can't get the originals, rectifiers like the FMG-33S and FMG-33R should be suitable substitutes.

 

[jasyip5052]

thanks Perry. i will try to looking for it.

 

[jasyip5052]

i still cannot get it, can i jst replace it with normal diode?

 

[Perry Babin]

The rectifier needs to have a fast or ultra-fast recovery time (50ns or less) so ordinary diodes won't work. They'll overheat and fail.
B&D Enterprises - Electronic Components Distributor

 

[jasyip5052]

thanks perry
i get the component d. i will replace it asap.

 

[jasyip5052]

i have replace the component already. then i hv do the testing for

Q617
E = 48.2
C = 48.9
B = 48.7

Q618
E = 46.4
C = 47.3
B = 47.0

Q619
E = 1.4
C = 48.9
B = 0.9

Q620
E = 0.9
C = -47.3
B = 0.9

TP5 + TP6 = -41.3
TP5 + TP7 = 41.2
TP1 + TP2 = 0
TP3 + TP4 = 0

output port Lch and Rch =38.7
the power LED and protection LED still blinking.

now the Q619 and Q620 jst in warm only.
is it still have any thing wrong?

 

[Perry Babin]

You should have more voltage on the collectors of Q617 and Q618. What is the voltage measured directly across the B+ and ground terminals of the amp?

The Zeners for Q619 and Q620 may be shorted. Check them.

 

[jasyip5052]

i don't know how to check the zener diode. but i had been replace the new 1 for both. but it still get the same.

voltage across B+ without connecting is 11.6V
voltage across B+ with connecting is 10.3V

the board for the amp can get buy or not.
bcoz i suspect it get short circuit of the board.

 

[Perry Babin]

With a power supply voltage of only 10.3v, I don't know what to expect, as far as the voltages on the board are concerned. You need to get a power supply that can supply at least 12v to the amp when it's on.

 

[jasyip5052]

oh.
thanks.
i will try to get the 12v power supply as soon as posible. then try it again.

 

[jasyip5052]

i had been test the The Zeners for Q619 and Q620, it really damage already.
i will replace it this weekend.

allow me to ask that, the 16V regulator circuit, if i change with the simple voltage regulator, it will be work or not?
thanks.

 

[Perry Babin]

You should be able to replace the discrete regulators with IC voltage regulators but there's really no point in doing that.

 

[jasyip5052]

i will replace the diode.

thanks for the command.

i jst want to know more about the amp reparing for the original circuit and the replacement circuit.

 

[jasyip5052]

sorry for late's reply. im try to borrow a power supply from my fren.
i hv replace the diode d. i get back the normal voltage form the regulator.
at the same time, i found the ZD504 & ZD502 was also damage.

after i replace it (with all the transistor and mosfet remove from board).
i get the normal voltage from Q414, Q416, Q407, Q408, Q411, Q412, and Q404.

then i try to put back Q418, the voltage for the collector, will get 53V. but it not getting HOT.

so that, i try to put back Q420, Q423, Q424, Q427, Q428.
when i power-up. R459 is getting very hot.
but if i remove the VR402 it is getting no HOT, but the reading still abnormal.

the next step i do is putting back all the transistor and mosfet and also VR402.
Q505, Q513,Q514,Q515, and Q516 getting very HOT.

is it still have any short circuit?

THANKS.

 

[Perry Babin]

If you set the bias pot fully counter-clockwise, does it reduce the heating of the output transistors?

 

[jasyip5052]

it just slowing down the heating speed.