Concept amp help please

joesch1999 · 2012-12-24 2:02 am

I have a concept amp I am working on problems in the p channel has bi polars I believe a1694 and compliment c4467 driver is bd14og I think I have tried looking them up with 2sa and 2sc keep getting a dead end what could I use instead as well as what driver any help would be great.

Perry Babin · 2012-12-24 5:26 pm

Which of those transistors tested as defective?

joesch1999 · 2012-12-25 2:44 am

a 1694 but i am just gonna replace all of them

jordan_ciaramit · 2012-12-25 5:47 am

Mouser has them. Search 2stc & 2sta.....MCM appears to have them too. Pacific semi has them.

Perry Babin · 2012-12-25 1:16 pm

I typically use the FJA4213 and FJA4313 as subs for this type of output transistor. These replace virtually all BJT outputs in this case style. The BD139 and BD140 are readily available from most distributors.

joesch1999 · 2013-03-01 9:34 am

Having some trouble with this amp took out p channel fets amp was going in and out of protection that made it stay on then the drivers b631 b630 got hot should I replace them and if so what r good replacements for those Korean drivers

Perry Babin · 2013-03-01 10:09 pm

If you're referring to the output transistors as FET, they are not. They are NPN and PNP bipolar junction transistors.

Why did you remove the output transistors? I'm assuming that you're referring to the new transistors.

joesch1999 · 2013-03-02 3:22 am

I removed the outputs and I know they r bipolar to find out why amp was in and out of protection after removed amp powered up but drivers got really hot I was thinking maybe I bought the wrong replacement driver to replace the b631

Perry Babin · 2013-03-02 3:40 am

The BD139 and 140 are relatively low voltage devices. If you used them in an application where the supply voltage exceeds their rated voltage, that could cause them to overheat.

joesch1999 · 2013-03-02 3:44 am

Ok I take it b631 replacement is bd139

Perry Babin · 2013-03-02 3:48 am

No. Look up the datasheets.

joesch1999 · 2013-03-02 3:55 am

I got 140 where the 631 was as it should be,still getting hot without fets in place can't find any resistors out of tolerance or diodes to zero ohms any ideas?

Perry Babin · 2013-03-02 4:12 am

Since I've never tried running this amp with no outputs, I can't tell you if it's normal for the drivers to get hot. It may be perfectly normal.

joesch1999 · 2013-03-02 4:26 am

it also has a cascade of jfets as well, its the dual mono amp, if i put all the outputs back it will go in and out of protection, they r all new, so can't be outputs, the good channel the outputs are out and drivers do not get hot nor resistors as they do on the bad side

joesch1999 · 2013-03-02 4:29 am

I found a 473k cap that might be bad its not reading ol but then again my fluke 179 wont read it anyway besides in ohms it is measuring different good side cap 600k ohms bad side 2.173k

joesch1999 · 2013-03-02 4:30 am

wish I had a esr meter

Perry Babin · 2013-03-02 2:51 pm

I've been trying to help but quite honestly, I can't understand the posts. Please use proper punctuation and complete sentences. Take the time to proofread what you've written. Don't send the post immediately. Wait about 10 minutes and re-read it to make sure that the message is clearly written.

joesch1999 · 2013-03-03 4:17 am

Sorry about that Perry should not be working on amps or communicating on 3 hours sleep lol, I figured it out was one of the to 92 fets it's fixed and all is well thank you

Concept amp help please

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