Memphis 16-pr1x1000 help

[rhempz01]

I recently obtained a Memphis 1000 and all the 3205 are violently blown, I have them to replace them, I just don't know what drives them. Or where they drivers are as they most definitely will need replacing. Any one know this board at all?

 

[Perry Babin]

Q14 and Q15 look like the drivers.

 

[rhempz01]

Think it all three of them?

 

[Perry Babin]

Three?

 

[rhempz01]

Will these replace the DY026. Im having difficulty finding the components. I looked though an old post a got a part number but still no luck. I found these

http://www.mouser.com/Search/ProductDetail.aspx?R=BCP56HXvirtualkey66840000virtualkey771-BCP56HX

 

[Perry Babin]

DY is the marking. KTA1661.

The 2SB1260 should be a good sub for a power supply driver.
http://www.mouser.com/ProductDetail...GAEpiMZZMshyDBzk1/Wi699iOF%2bvXIMDgSak7uGF5c=

 

[rhempz01]

ok thanks perry.

 

[rhempz01]

Full board for forum

 

[rhempz01]

Is it just hem two Perry, replace all the 3205 and the drivers and b+ right away or should I limit and test something before hand. The PS fets were violently blown.

 

[Perry Babin]

As far as I can tell, those are the only 2 driver transistors. They may have survived.

Never go straight to full current when initially testing if you have a limiter.

Before installing the FETs, I'd suggest checking the drive signal to the gate resistors.

 

[rhempz01]

I just received the limiter you suggested today, never again will I haft to hope for the best....so b+ and test where the PS fets would go for dc?

 

[rhempz01]

What should I get the gate resistors are 100ohm. So main ground and the pad with the gate, powered with limiter

 

[Perry Babin]

100 ohm is typically too high a value for the gate resistors for 3205s unless the circuit has additional deadtime built in. Typically, 47 ohm resistors are used.

What is the resistance between pins 4 and 7 of the 494, no power applied?

Do you have a scope?

 

[rhempz01]

No scope Perry, the 3205 and drivers are out of circuit I ordered extra drivers. 21.9k

 

[rhempz01]

Here a picture, do u think 3205 are supposed to be in it?

 

[Perry Babin]

The originals are 3205s. It appears to have deadtime programed in.

 

[rhempz01]

So I should test the gate signal. With b+? Start there?

 

[Perry Babin]

Yes

 

[rhempz01]

OK so with new drivers installed and the current limiter, I have a constant 4.36v on the gates

 

[Perry Babin]

That's probably OK.