Now why is this happening?

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Sammas

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Oh council of the wise and knowledgable.

Having tested the master module and a dozen or so channel strips all was going well with my Soundtracs IL3632... I've ran audio from a CD player though the line inputs on the first two channels then managed to route them through the next 14-16 channels... testing eq's, pans, monitor paths, faders, routing buttons, etc, etc...

Having covered that I'd thought I would step it up a notch and wire up 8 balanced TRS jacks to a 56 pin elco to test the multitrack returns and do some more critical listening. The 8 TRS jacks were to interface with an RME ad-8 converter. As per the manual's instructions I only connected the shield at the source end, so it was connected to the sleeve of the TRS only.

Just after I plugged it all in I noticed the smell of burning resistors. R34 & R35 to be exact. These two are not jumpered with the -10 link. You will find them on the schem on the left hand edge at the monitor input.

I've double checked the elco loom wiring and it checks out fine on both ends. I've taken a look through the piles of ribbon cables that link the elco connects to the patchbay then on to the modules and it all looks fine.

Any ideas?

Soundtracs_IL3632.jpg



If nothing else here is the schematic of the EQ of a Soundtracs IL3632 which a few people asked for in another thread a while back. [/img]
 

gyraf

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to burn resistors, you will need to have quite some error voltage!! check the voltage at the resistors - and double-check board connections and interconnections..!
 

Sammas

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Thats exactly what I was thinking, but I thought i'd ask anyway.

As we speak the TT patchbay has been disconnected and I am sifting through the piles and piles of ribbon cables, testing continuity, checking connections, etc, etc...

Once it is all back together i'll give it another go and measure the voltages.
 

dale116dot7

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If you've burned resistors, then the IC is likely gone too. You probably should replace IC4 whether it still works or not. If the input resistors are burnt up then the input transistors have taken a hard hit and are probably going to generate a lot of input noise, if they work at all.

Check for grounding. If the shields are only connected at one side, then the chassis ground path MUST provide the other side of the ground. Before connecting cabling up again, measure AC and DC voltage between the chassis ground (shields) of the two pieces of gear. There should be none.
 

Sammas

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Thanks Gyraf and Dale! :thumb:

I caught it pretty quickly... The resistors are far from destroyed but i'll yank them out and replace them along with the IC's too.

Thanks! :thumb:
 
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