Started tubelab SE checkout and R5 went into fusion

[jamicomon]

Hey everyone,

I've spent days lurking and going through tons of posts on this forum.

My amp was blowing fuses I couldn't figure out where the smoke was coming from so I put in a 4A fuse.

R5 became glowing red and smoked out.

What should I check first?

PCB:
https://www.dropbox.com/s/6a0homdplmkzog0/2014-11-16 14.47.18.jpg?dl=0

https://www.dropbox.com/s/4rfr6uh45dvpnlp/2014-11-16 14.47.10.jpg?dl=0

https://www.dropbox.com/s/9xkaes0rzlp0tq7/2014-11-16 13.32.47.jpg?dl=0


Case:
https://www.dropbox.com/s/pz96ja55lbnpn9s/2014-11-01 21.13.06.jpg?dl=0


Thanks

 

[zimmer64]

Check your solid state diodes. One of them might have a dead short. (happened in my SSE and I had the same symptoms.)

 

[jamicomon]

Thank you for your quick response.

I'm getting about 15k resistance between the cathode and anode on both.

I did order some of the recommended newer models for replacement but they ship from china so i won't know for a while.

Anything else i could check?

 

[ahankinson]

If you're getting them from e-bay make sure you've actually got legit parts and not just fakes. It might say one thing, but have completely different insides.

 

[zxx222]

Check polarity of DSEI12-12A, from your photo it looks like that you soldered them in wrong way, look at photo of my board.

One more thing - connect opt's to speakers or dummy load, before putting in power tubes, otherwise you may smoke your opt's, from your photos I see that secondaries are not connected to anything.

 

[canersahin]

Where did you get the coolers from?

Check polarity of DSEI12-12A, from your photo it looks like that you soldered them in wrong way, look at photo of my board.

One more thing - connect opt's to speakers or dummy load, before putting in power tubes, otherwise you may smoke your opt's, from your photos I see that secondaries are not connected to anything.

 

[jamicomon]

Thank you zxx222.

The diodes are definitely in reverse. Don't know how I missed that..

I will fix it but i will have to wait for my replacement R5 270ohm resistor to arrive.

For dummy load i have a pair of old sony 3 way speakers that i stripped with the crossover still intact, so that will do nicely.


As for canersahin, the big one is an old aftermarket thermalright HR motherboard cooler. The other ones are just old stock motherboard coolers.

As for the case, I used a Bitfenix Prodigy M since I have no woodworking skills or tools and wasn't using it anymore.

Thank you everyone! This community is awesome.