Amplifer 1 channel dead .Please help

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Pass lover

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Joined 2006
#1
Hi, I think there may be sonmeone could help.

My Carver TFM 15CB has 1 channel dead

The TFM15CB has built-in passive preamp (which I believe it can be bypassed ). When having jumped the signal( routing the signal directly from input socket to the amp CB), I forgot to turn down the CD player output level. The result is the sound is VERY loud. I had to stop the CD player immediately.

When I jumped back the signal route as original, there is no sound on BOTH amp channels. Leaving it for about 3 hour ( still in original state), turn it on, there is only ONE channel work ( the LEFT one)

I don’t know what happen to the power section. I think the too- loud signal hurt something in the CB

Dose anyone encounte this problem before?

I still have a nother Carver with the same model ready for mono bridged. What should I check?

Please give your advice
http://i24.photobucket.com/albums/c48/JULIOVO9999/Modem/InsidePreandPower1.jpg

http://i24.photobucket.com/albums/c48/JULIOVO9999/Modem/Inside2.jpg
 
#5
jaycee said:
Looks like the preamp is just pots, so it's probably just a bad pot on that channel... when bridged the signal only goes by the working channel and it's OK.

Without seeing a schematic it's tough to be sure
Click to expand...

Thanks for your idea. But as I said it worked perfectly, it is true. I have a nother amp ( the same model: TFM15CB). Having made a blind test in bridged model, I found that the 'problem' amp sounded even a bit louder than the normal one. That made me confused

I also found the website address to down load the schematic. But it is a bit difficult to read due to poor copy quality. I still tried to find the way to post it on.

the schematic was downloaded from www.thecarversite.com after registering
 
#7
jleaman said:
have you taken the board out that holds the 2 pot ? Maybe give them a quick solder job ? They are probably used lots ( ie turned up and down ) so a cold solder could effect this.

J'
Click to expand...

Hi, I did check the preamp board. It is working. Now I have just bought a preamp, plug it directly to the amp, still 1 channel sound. I think the power section has problem

However, it made me mad when mono bridge the amp, it still sound percfectly😕
 
#8
Pass lover said:
Hi, I did check the preamp board. It is working. Now I have just bought a preamp, plug it directly to the amp, still 1 channel sound. I think the power section has problem

However, it made me mad when mono bridge the amp, it still sound percfectly😕
Click to expand...

If one channel is not working then when you bridge it, there will be no difference.

I'll ask some questions,

So both channels actually work ?

when you change the cable from the front board a to be or b to a, vice versa they both work when testing them ? with the good one..


?

Jase
 
#9
jleaman said:
If one channel is not working then when you bridge it, there will be no difference.

I'll ask some questions,

So both channels actually work ?

when you change the cable from the front board a to be or b to a, vice versa they both work when testing them ? with the good one..?

Jase
Click to expand...

Hi Jase

A test was made with the good amp ( plug B to A vice versa). The good amp work perfectly in stereo and in bridge mode).

When being bridged, ( both amps are in original condition. That means thers is no mod here: the cable B in B position, and cable A in A ...no change at all) I can say that the good and the 'problem' amp sound identically. The 'problem' amp sound abit lounder than the good ( but not significantly)

That is why it made me confused

In theory, the 'problem' amp must sound less lound than the good due to having 1 channel dead
 
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