T15 not working....what have i blown??

[glide 1]

Hi Tim,

I just finished building 2 T15's, a D11 and an A12. All work great except for one T15, i accidentally installed OPA 134PA in U3 and THAT 1646 in U4. Noticed that U6 (LM337) got very hot before realizing that i had swopped them around.

What do you recommend i check 1st? Are U3, U4, U6 blown? I had it on for less than a min. and did'nt notice anything burnt visually.

I'm thinking of using the U4 and U3 from the other working unit just to see if its those parts that are blown, but thought i'de ask here first. I also have a spare LM337 to try if you think that is blown.

Hoping you can help, thanks.

glide 1

[tpryan]

You may not have blown anything. Remove the parts from U3 and U4 and apply power. Test for proper voltages at U1 or U2. It's unlikely the LM337 was damaged. Reinstall the other ICs one at a time, starting with the OPA134. You may get lucky and not have to replace anything. Let us know what you find.

[glide 1]

hi Tim, i think the OPA134 is dead. Will the OPA132 work as a replacement for this? Its the only one i can get locally. What could i expect performance wise? thanks

[tpryan]

OPA132 should work great if you can find it in an 8 pin DIP package.

[glide 1]

Thanks a lot tim. I was able to replace it with the OPA132U (modified to fit 8pdip socket), so i now have 2 N72's, 2 T15's, 1 D11, and an A12 all working great.

Here's a couple of pics of what i did:




Can't say enough about how good these pres are and the top class service you provide. Looking forward to getting my final 2 pres to fill up the CH01 chassis.