VP312DI build - No Sound OPAMP getting HOT!!!

[New Soul Rebel]

Guys, i'm bloody stuck on a VP312DI (Version C.1) build

Anyone out there help?

Here's the symptoms...

Phantom LED ON
I can clearly hear both relays
No sound at either end - I.e. no sound on DI, No sound on Mic Pre.
Opamp gets very hot in less than 30 seconds

Has anyone troubleshooted these exact symptoms? I have checked all my solders (which I will do once again). All the resistors AND caps are DEFINITELY in the right place. I am going to check my relays once again, but why would they both be working if they weren't soldered probably.

I'm proper perplexed on this.

What's the best way to troubleshoot a build?

Could it be the bourns pots? I've had this problem before where the pre has gone down, because of a cold solder on the bourns pot, but as soon as I resoldered it, it worked perfectly. Would this cause the opamp to get hot?

Any thoughts gratefully appreciated.

Cheers, Matt

 

[RuudNL]

In fact there is not very much that can go wrong...
The first thing I think of is that the voltages on the OpAmp are wrong, or the polarity is reversed.
Did you check this?
A shorted OpAmp output might warm up the thing if you drive it 'loud', but that would not be my first thought.

 

[nielsk]

Could be a bad op amp. Pull it & check power & gnd at the socket, find a way to test op amp or substitute...

 

[New Soul Rebel]

Hi Guys

Firstly thanks for the replies. I'm going to get a chance to look at this in the next hour or two.

I'll report back with more pics and some other thoughts.

Thanks for now

Cheers

Matt

 

[jsteiger]

Matt

This should not be a new thread topic. These same problems were brought up in the VP312DI build thread. I responded with some things for you to do. First being check/swap the opamp.

I will post some other thing there now. http://www.groupdiy.com/index.php?topic=40821.msg598820#msg598820

I suggest we let this thread die and not clutter up the forum. Ethan has made great steps to make things easier to find around here and this thread is counter-productive IMHO.

Cheers, Jeff