R9 390 8Gb - Broken Transistor and missing components?

[dicky96]

Hi guys
I have a R9 390 here. The owner sent it to me with a smd 1AM transistor (one leg broken off) taped to the heatsink

He says he bought this used as 'working' on ebay, put it on one side for about a year (never tested it) and when he came to use it, it does not work

He then spotted the broken transistor in the bottom of the box

At this time it was much too late to return it

He sent me some pics where he says the transistor comes from (not sure how he knows for sure).

Under the microscope it does look like some transistor pads are missing here, but it also looks lie a couple other parts may have been desoldered. Does anyone know what parts should be here?

See pics

Cheers

[dicky96]

Re: R9 390 8Gb - Broken Transistor and missing components?

I'm trying to identify these broken or missing parts

It appears that the pads have been ripped off the board where the '1AM 2' transistor supposedly came from. The actual transistor has one leg broken off

If I have the correct datasheet then this is an NPN SOT23 transistor and the middle leg is the collector
https://pdf1.alldatasheet.es/datashe...ICTEK/1AM.html

That pad goes to one of the missing components and the other end of this connects to ground. So I assume that must be a capacitor as I don't see any point to connect the collector of an NPN transistor to ground via a resistor. I also assume the collector pad connects somewhere else as well

There appears to be a 5 pin device missing but the pad layout does not look correct for a SOT23-5 device. I can see there is another 'missing' component also connecting from one of the 5 pins to ground - this actually looks to be a broken off component. The other end also goes to ground so I am guessing capacitor

One of the pins of this 5 pin device goes to the base of the missing '1AM 2' via a 10K resistor and this forms a voltage divider by the looks of it with another 10K resistor but I am not sure where the other end of that one goes

See pic - it will explain this much clearer.

It seems to me if I could know what the 5 pin device is, the datasheet would probably help and I could reconstruct this circuit using a couple of capacitors plus the 1AM 2

I'm trying my best to help myself here - but can anyone give me a hand with this?

Much appreciated
Richard

[dicky96]

Re: R9 390 8Gb - Broken Transistor and missing components?

Guys - I've tried to work out as best as I can what the missing parts are

If anyone has 20 mins to spare could you please check this video out and hopefully advise me on the possibilities to repair this?

https://www.youtube.com/watch?v=DvPjTfO3CG0

Thanks