Troubleshooting a mint

[Lavalamp]

I need some guidance in locating the problem in my newly constructed mint.

The left channel works fine. I assume therefore that the power supply must be ok. I'm getting no sound at all from the right channel.

I can measure voltage either side of R1 on the good channel, but am getting nothing on the bad channel. I'm thinking maybe there is a problem with C1.

I decided to dispense with the pot, and use it as the power amp, so I did two wire links to what I worked out to be the correct pads for bypassing the volume pot. That could also be the problem.

Can anybody point me in the right direction? I'm quite new to trying to trouble shoot a project.

Thanks.

 

[skyskraper]

can you try do a continuity check from the input of the right hand channel to where it goes in to c1? and also check that you have wired the right channel correctly on the jack. some pics of the board details would be a great help

 

[Lavalamp]

I have continuity from the jack to C1. The jack is wired correctly. Might be able to post some pictures tomorrow, if I can borrow a camera tonight.

 

[Pars]

Take a look at this to see if you have things wired correctly. If you want to bypass the pot, and you want to use the normal input pads (and this is a Tangent MINT board), you would simply jumper input to output on the pot pads (pins 1,4,5 and 6, 1 and 6 = one channel and 4 and 5 the other IIRC). Pin numbering with pot shaft facing you, pins down, from left to right.

 

[n_maher]

I'm not trying to be a wise guy here but are you sure that you've got your input and output jacks wired correctly? You wouldn't be the first, trust me

.

N

P.s. If you can, post up some pictures of the board and the wiring and maybe one of us can spot what's wrong.

 

[Lavalamp]

My wire links bypassing the volume pot seem to be in the correct position. The jacks are wired correctly. I have done a continuity check from the plug on my interconnect to make sure and it all comes up good. I've just replaced both C1's. I can't see any solder bridges or dry joints.

Any other suggestions? Might be able to post pictures tomorrow.

 

[Lavalamp]

I have taken some photos but the files are too large to attach.

Anybody like to receive them as emails to look at?

 

[Pars]

Quote:

Originally Posted by Lavalamp My wire links bypassing the volume pot seem to be in the correct position. The jacks are wired correctly. I have done a continuity check from the plug on my interconnect to make sure and it all comes up good. I've just replaced both C1's. I can't see any solder bridges or dry joints. Any other suggestions? Might be able to post pictures tomorrow.

Two things to try:


1) Ohm out the connection from the amp side of C1 thru to the opamp... everything OK? Also check for shorts... use magnification.

2) You could jumper Ci (just tack a jumper across it on the bottom) and check for continuity all the way thru to the opamp, and also voltage on R1 with an input signal.

 

[Lavalamp]

I found the problem. I used dip 8 sockets for my resistors. With the PCB covered up, I didn't realise that the two banks of resistors are mirror images of each other, D'oh!

She's singing very nicely as I type. Definately a step up from my c-moy.

Thanks for everyone's suggestions. You're a very helpful bunch of guys.