Soundstream Reference 404

[kmarei]

i picked up a Soundstream reference 404
but the power supply has issues
the mosfets for the power supply are bad
or at least 2 or 3 are
i will replace all 6
they are smp50n06-25, but i can't find them on mouser


but is there anything else i should check before i order the parts?
i know one resistor looks dodgy( marked in red), so i will order that as well
but if it's known 2 mosfets are burnt, is there something to check ?

[Perry Babin]

All 6 FETs need to be replaced. IRFZ44s will work.

You need to check the driver transistors (especially the 2SA1562).

Check the rectifiers and the output transistors to see if any are shorted.

[kmarei]

so all 6 of group 1 are to be replaced with IRFZ44
driver transistors are groups 4 and 5? i should check those.
what about 2 and 3? are those power circuit or related to the outputs?



the rectifiers are the grey rectangles with the lightning symbol on them?
measure resistance of those?
they all measure 0.1 ohm

[kmarei]

i tried both digikey and mouser
they both don't have the IRFZ44s
is it the same as IRFZ44? (no s at the end)

[Perry Babin]

The components with the lightning symbols are circuit breakers.

2 = rectifiers
3 = regulators
4 and 5 = output transistors

If you notice, all of the important letters are capitalized. The lower case 's' makes it plural.

[kmarei]

Originally Posted by Perry Babin

The components with the lightning symbols are circuit breakers.

2 = rectifiers
3 = regulators
4 and 5 = output transistors

If you notice, all of the important letters are capitalized. The lower case 's' makes it plural.

i'm having a hard time testing the mosfets
i'm getting weird measurements
none of the readings match
and i don't want to unsolder all of them to do the correct testing
i might as well replace them in the process

do you think its ok if i just replace all of them?
doesn't that buy me peace of mind later on?
don't want to replace 3 now, only for the 4th to die on me later
plus this unit is in very good condition both inside and out, so i don't mind investing in it to make it work at its best

i can't find the part number you listed for the driver transistors 2SA1562
i found the IRFZ44s so i will order 6 of those
now i need the part numbers for the 2 regulators, the 4 rectifiers, and the 16 driver transistors

thank you very much

[Perry Babin]

There are only 6 MOSFETS in this amp. You already stated that you were going to replace all 6.

The BD140 may be good sub but you'll have to install it facing the opposite direction because the pin configuration is reversed.

It's unlikely that the regulators have failed. The rectifiers are easy enough to check in the circuit.

Are you referring to the output transistors as 'driver' transistors?

[kmarei]

Originally Posted by Perry Babin

There are only 6 MOSFETS in this amp. You already stated that you were going to replace all 6.

The BD140 may be good sub but you'll have to install it facing the opposite direction because the pin configuration is reversed.

It's unlikely that the regulators have failed. The rectifiers are easy enough to check in the circuit.

Are you referring to the output transistors as 'driver' transistors?

sorry i might be using the wrong terminology
i refer to all things with 3 legs as mosfets

i meant the 8 output transistors for each channel
but instead of testing the rectifiers and regulators, i was thinking of just replacing them
unless you have any data on what numbers i should be getting if i measure them in circuit?

when i flipped over one of the output transistors, it says TIP107
those i found.
is that what part you were reffering to when you said 2SA1562?

[mike49504]

The Power supply fets All have to be replaced . The ones with the yellow arrow pointing to them..

The outputs are the ones in the pic of the red arrows pointing to them There should be Both Tip 107's and Tip 102's in the red boxes with the arrows pointning to them..


The drivers for the power supply fets are circled on top of the board in the 2nd pic u need to test thoose also..


For testing the outputs in circuit set your meter to diode check and test as followed..

Legs 1-2
Legs 1-3
Legs 2-3

Do you get anything near 0 when u test them if so post the results as followed

1-2:
1-3:
2-3:

The rectifiers and regulators very rarely fail you dont need to replace them if they arent defective

[Perry Babin]

The 2SA1562 driver transistor looks like the one in the attached photo.

If you don't know the name of a component, ask.

The TIP102s and TIP107s are the output transistors. They are darlington BJTs, not MOSFETs.