Audison LRX5 600 No Sound

[Frycztech]

Yes I did but iam still confused because I dont see any 8 pin chips near the pots. Sorry if i spoke wrong I was just trying to be proactive.

 

[Perry Babin]

Why didn't you say that there were no 8-pin op-amps near the bias pots?

This amp appears to be too different for me to be of any help. I was expecting the design that had op-amps like the one in the photo below.

 

[Frycztech]

Perry,

Sorry I was a little confused and I was looking for something that I was unsure about. Here is a picture around one of the pots.

Also after removing some of the heat sinks I found one of the power FET's to be blown. I measure all the center pins and have the 13.24vdc

 

[Perry Babin]

Without a wider photo or a description of how they're being used in the circuit, I can't offer any more advice than to replace the blown FETs.

You removed the spring clips that hold the semiconductors tight against the heatsink. The heatsink is the large massive piece of aluminum that soaks up the heat from the semiconductors.

 

[Frycztech]

Here are some better photos. I removed the spring clips because I saw some brown powder on the clips and board. When I removed them that is what I saw.

 

[Perry Babin]

It appears that they are the PS FETs. If the PS is blown, you're not likely to have many voltages present in the amp. That's why I asked about rail voltage earlier.

The gate resistors and the driver transistors may have been damaged as well.

 

[Frycztech]

Iam looking to replace the power transistors to try to power the amp up for further testing. They are BUZ110S I belive this is the datasheet:
BUZ110S pdf, BUZ110S description, BUZ110S datasheets, BUZ110S view ::: ALLDATASHEET :::

Iam having trouble finding replacements. Is there any part number that these can be changed over to?

Also there are U1620, and U1620R are these the voltage dividers? Should they be replaced? If so what would a good replacement for them be?

I will have to get the measurement to replace the 2.2k gate resistors.

Thanks in advance

 

[twilliar]

Iam looking to replace the power transistors to try to power the amp up for further testing. They are BUZ110S I belive this is the datasheet:
BUZ110S pdf, BUZ110S description, BUZ110S datasheets, BUZ110S view ::: ALLDATASHEET :::

Iam having trouble finding replacements. Is there any part number that these can be changed over to?

Here is a link to a cross-reference source
MOSFET Cross-reference Search | Equivalent Transistors
It shows you may be able to use the IRFZ4410Z which is available through Mouser.

Also there are U1620, and U1620R are these the voltage dividers? Should they be replaced? If so what would a good replacement for them be?

Those are the rectifiers. Something like the MUR1620, again through Mouser. Replace only if they test bad.

I will have to get the measurement to replace the 2.2k gate resistors.

Thanks in advance

People may disagree, but when I started repairing amplifiers I pulled the rectifiers out to give me the ability to repair the power supply without worry.
If you do make sure you mark the direction if you have any doubt about the positive, negative relation.
Take it slow as not to confuse you. I see you have another amp you are working on that has a completely different circuit topology.

 

[Perry Babin]

The IFR3205 should be a good sub. Use 47 ohm gate resistors.

The PS gate resistors are not 2.2k.

The 1620s are rectifiers. They don't need to be replaced unless they're defective.

 

[Frycztech]

The IFR3205 should be a good sub. Use 47 ohm gate resistors.

The PS gate resistors are not 2.2k.

The 1620s are rectifiers. They don't need to be replaced unless they're defective.

It looks like the resistors off the gates have 222 on the top of them. Am I looking at the wrong ones? I thought they were R2,R3,R4,R5,R6

 

[Perry Babin]

Bear in mind that I have no information on this amp except what you provide. Good quality, high resolution images would help reduce guesswork.

The 2.2k are likely pulldown resistors.

The gate resistors will be much lower in value.

I suggested 47 ohm. If the original gate resistors are OK and 47 ohms or below, you can leave them.

 

[Frycztech]

Bear in mind that I have no information on this amp except what you provide. Good quality, high resolution images would help reduce guesswork.

The 2.2k are likely pulldown resistors.

The gate resistors will be much lower in value.

I suggested 47 ohm. If the original gate resistors are OK and 47 ohms or below, you can leave them.

Here are some more pictures. I will take some better ones when I pull the board from the case.

 

[Perry Babin]

I see at least three 47 ohm gate resistors.

 

[jkrokenberger]

The two left-most TO-220 packages are rectifiers. I think the "222" resistors are for the gates of the 3 FETs to the right of the rectifiers.

 

[Perry Babin]

It makes no sense for there to be 47 ohm resistors there if they are not used for the gates. 2.2k resistors are too high of a value for gate resistors unless there is a LOT of deadtime or parallel diodes for pulldown.

 

[Frycztech]

Should there be 6 gate resistors? 3 on each side? I want to look for them on the opposite side. I cant get the caliper on the 47ohm but the 2.2k are .060in. what would the wattage be?

 

[Perry Babin]

You should be measuring with your multimeter.

 

[Frycztech]

The IFR3205 should be a good sub. Use 47 ohm gate resistors.

The PS gate resistors are not 2.2k.

The 1620s are rectifiers. They don't need to be replaced unless they're defective.

Would this be a good replacement?

IRF3205PBF Infineon Technologies | Mouser

 

[Frycztech]

You should be measuring with your multimeter.

For getting the wattage of the resistor?

 

[Perry Babin]

Aren't you looking for the gate resistors?