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-   -   R2 fire - blown (https://www.diyaudio.com/forums/tubelab/309114-r2-fire-blown.html)

capitanalga 18th June 2017 09:20 AM

R2 fire - blown
 
Hi there,

Something horrible happened... after two years of work, I managed to finish my sse. Everything checked, apparently everything ok.. when I turn on, check light turns on and valves start to glow. After, let's say 15 seconds, R2 burns with fire. I will post some pics later (but there is actually not more to see than what's described). R2 was 150ohm 3w 5% axial (23J150E-ND). My questions:

1- what can cause r2 to burn?
2- I have desoldered r2, will just replacing r2 work?
3- what should I check?
4- should I start a brand new pic?

Thanks and best regards!!

JonSnell Electronic 18th June 2017 09:49 AM

Schematic? Where does R2 sit? Photo?

capitanalga 18th June 2017 10:24 AM

3 Attachment(s)
Hi, thanks for quick reply. Find attached photos. What do you mean exactly with schematics, what should I post? I have configured like that: [http://www.tubelab.com/images/Assemb...ode_noCFB.jpg]

Thanks and sorry if my questions are to obvious!

Attachment 621672

Attachment 621673

Attachment 621681

mkane77g 18th June 2017 05:10 PM

I'm not trying to be a wise guy but some of those solder joints are in serious need of attention. I would double check everything.

capitanalga 18th June 2017 05:48 PM

Quote:

Originally Posted by mkane77g (https://www.diyaudio.com/forums/tubelab/309114-r2-fire-blown-post5110758.html#post5110758)
I'm not trying to be a wise guy but some of those solder joints are in serious need of attention. I would double check everything.

Sure! Thanks! How could you check them? And if they're not good? Desolder and solder again?

Thx!

Nikon1975 18th June 2017 06:05 PM

R2 should be 150K not 150 ohm. if it was 150 it tried to dissipate almost 1000w

D.

JMFahey 18th June 2017 08:14 PM

Please post a readable schematic, I am unable to open the Tubelab page (page not found), maybe itīs available only to members.

Nikon1975 18th June 2017 08:33 PM

Be sure you did not swap R1 and R2, if you did not use a choke. The bad news is that you might have damaged the rectifier. The good news is that all the rest should be intact.

D.

vinylkid58 18th June 2017 08:39 PM

Quote:

Originally Posted by JMFahey (https://www.diyaudio.com/forums/tubelab/309114-r2-fire-blown-post5110925.html#post5110925)
Please post a readable schematic, I am unable to open the Tubelab page (page not found), maybe itīs available only to members.

Here's the main page: Tubelab SSE | Tubelab

jeff

JMFahey 18th June 2017 09:09 PM

Thanks :)
I was actually expecting this being posted here:
https://www.tubelab.com/images/Assem..._Sch_11-08.jpg

instead of having to navigate an external page, but hey, better than nothing :)

And yes, *seeing* the schematic itīs easy to imagine what happened. :(

Hope the rectifier is fine .
Maybe the SS/Tube switch was ON and the SS diodes took the surge.

As a side comment, is that amp finished?
I see lots of too long cable all over the place, some of it with free ends.

As of soldering, itīs really hard to solder well with mandatory lead free type, canīt you get a little old style one somewhere?
A tiny bit of it added to each already soldered junction will make it way more reliable.

In any case, congratulations on your build and welcome to a fascinating Hobby :)


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