t-amp stealth mod problem - no sound output at all...

[Davet]

Voltage

I saw you had taken C!) off the board after my last post (sorry). What is the voltage reading at C10?

Does the LED light up?

 

[stephanko]

- voltage at C10 location (while removed) is 13.2V
- LED is on.

 

[audio1st]

hello stephanko
did the amp work before you modded it?

 

[stephanko]

hate to admit ..... worked fine ....

 

[Lostcause]

OK so lets do this by elimination.
Unsolder the wires from one of the RCA's
Just one channel will do.
temporarily clip the input to the wire leading to the cap on that channel, and clip the ground on.
Use your i-pod as the volume control.
If nothing happens then we know it's not the pot or the RCA connections shorting anything out.

 

[audio1st]

Hello again
it seems that your speaker - v'se are not connected

 

[Lostcause]

Hello again
it seems that your speaker - v'se are not connected

Good point, have you got a picture of the whole amps output stage?

 

[stephanko]

Hello Lostcause: I will do, might not happen 'til tomorrow

Hello audio1st: Not sure what a v'se is..? Please enlighten me

 

[audio1st]

Hi Lee
it must be where the speaker wires are soldered to the board.
stepanko, check all your speaker wire soldering..

 

[audio1st]

Hello Lostcause: I will do, might not happen 'til tomorrow

Hello audio1st: Not sure what a v'se is..? Please enlighten me

it should have been - ve, negative..
resistance from input to output should be the same at all speaker terminals..

 

[Saturnus]

Damn, yeah, that's true sine it's a BTL design all outputs should the resistance from the input.

 

[stephanko]

- sorry, still don't understand the 've' thing.

- Re-checked (if I understood you correctly) resistance between RCA+ and speaker+ and speaker-
to speaker+: 53k
to speaker-: infinity


- here is a picture of one speaker soldering as well as the power in soldering.

 

[stephanko]

corresponding top view picture (speaker wires, etc)

 

[audio1st]

to speaker -, should be 50k

 

[audio1st]

measure resistance from the points shown in the attatched picture and your speaker terminals. reading should be less than 1 ohm..

 

[stephanko]

ok, checked one more time:

RCA+ (left) to speaker+ (left): 53k
RCA+ (left) to speaker- (left): infinity

RCA+ (right) to speaker+ (right): 53k
RCA+ (right) to speaker- (right): infinity

Are we on to something here?

 

[stephanko]

audio1st:
see the picture for results..... so no wonder I have no output signal, correct? I should probably try to connect the negative side of the speaker to the points labeled L- or R- on your picture?

Question: As I was pondering this.... I realized I only soldered the speaker wires on the bottom of the PCB. Could this be the reason for not having any continuity? Should I try to solder them on the top side of the PCB as well?

 

[audio1st]

It is definitely the soldering of the white speaker leads..try soldering both sides of the board..

 

[Saturnus]

Question: As I was pondering this.... I realized I only soldered the speaker wires on the bottom of the PCB. Could this be the reason for not having any continuity? Should I try to solder them on the top side of the PCB as well?

Yup, if you look closely at your board you'll see that the - is only connected on the top part of the board and + is only connected on the bottom side for the R connectors. And both only on the top side the L connectors but I guess you just lucky getting the plus one to work. I assume you soldered the plusses first.

 

[stephanko]

so it holds true one more time..... if you assume you make an *** out of U and ME. My (false) assumption was that the the top and bottom side of the PCB (looking at a single hole) are contacted through...

I will heat up the iron....... and keep you posted (hopefully with good news)

Thanks!