>what a headache
???
See, I fully disagree.
This is just part of the fun.
If it is not, then I don't understand anything of this passtime.
If you want to save your self this "headache", ....
buy an amp???
You say you matched the bc550 (useless I think) but did you just
take out one of the bc550 and checked it again?
I hate to say this, but I think you are going around this in a
wrong, and maybe a little sloppy, way. (no bad intentions)
In this light, rechecking all resistors with an ohm meter is probably
a good idea. But I wouldn't hold my breath.
I do not understand why you are saying " I am 100% sure that
....".
Being sure is good. Making sure, by rechecking, even if this means
taking one or all parts out of the PCB, is BETTER.
Realy no offence intended.
Talk to you tomorrow. And remember: Giving up is not an option!
Cheerup, please.
???
See, I fully disagree.
This is just part of the fun.
If it is not, then I don't understand anything of this passtime.
If you want to save your self this "headache", ....
buy an amp???
You say you matched the bc550 (useless I think) but did you just
take out one of the bc550 and checked it again?
I hate to say this, but I think you are going around this in a
wrong, and maybe a little sloppy, way. (no bad intentions)
In this light, rechecking all resistors with an ohm meter is probably
a good idea. But I wouldn't hold my breath.
I do not understand why you are saying " I am 100% sure that
....".
Being sure is good. Making sure, by rechecking, even if this means
taking one or all parts out of the PCB, is BETTER.
Realy no offence intended.
Talk to you tomorrow. And remember: Giving up is not an option!
Cheerup, please.
rtirion said:
Tells me that the differential pair is not conducting - no voltage across their load resistors (same as gate voltage in gain devices)
This is a consequence of the gain devices not conducting - the CCS is trying to increase the voltage to get current to flow. That's why the 100R are hot.
Again a consequence of the differential pair not conducting -
The BC550C voltages seem OK to me based on the input differential not working. Notice that you have ~4V E-C, which is what it should be to get the CCS MOSFET to conduct. This CCS is upside down compared to the usual configuration - the current sense resistor is not attached to a rail, so you need to look at relative voltages inside it to determine if faulty.
Since both sides seem to be doing the same thing, it points to something they have in common.
My bet is on the input differential pair gone bad. Replace both of them and your amp should spring to life.
good morning.
headache was from zens v4, i would like never to back to theese times.. there is lot of diferences between speakers and amps conctruction.. to but a new amp is not bad idea,just 5 aleph xa100 amps costs LITTLE too much for my wallet. and building myself I can put better details(manufacturers-can not.inspite how much engineers would like to put better parts , others do not let this. I have opened many xxxxeur and even few xxxxx amps, CDP and especialy speakers and find that)
I mached bc550c this way- tooked 200pieces, mached them to the same hfe, then mached again(because values difers), almos tall values differs , when I found 4bc550 c which measures constantly all the time I have a one pair. and then again .
I am sure 100% because I dissolder some of parts include bc550c to check, I do not want to desolder all parts but SOMWHERE i DID MISTAKE.and this was to all 10 boards.
now I am going to check it all again..
input diferential pair is pair 9610? when I measure i get very close values to all paired devices including 240 and 9610. maybe litle bit helped that I used 1% tolerance metal film resisitors and also mached them for pairs.
BobElis- how can irf9610 to break down? if this happens on one board I can understand,maybe accidently, but if on all that shuold be somewhere problems. but I will try replace 9610 with soem unmached .I will let you know results, thanks again..
headache was from zens v4, i would like never to back to theese times.. there is lot of diferences between speakers and amps conctruction.. to but a new amp is not bad idea,just 5 aleph xa100 amps costs LITTLE too much for my wallet. and building myself I can put better details(manufacturers-can not.inspite how much engineers would like to put better parts , others do not let this. I have opened many xxxxeur and even few xxxxx amps, CDP and especialy speakers and find that)
I mached bc550c this way- tooked 200pieces, mached them to the same hfe, then mached again(because values difers), almos tall values differs , when I found 4bc550 c which measures constantly all the time I have a one pair. and then again .
I am sure 100% because I dissolder some of parts include bc550c to check, I do not want to desolder all parts but SOMWHERE i DID MISTAKE.and this was to all 10 boards.
now I am going to check it all again..
input diferential pair is pair 9610? when I measure i get very close values to all paired devices including 240 and 9610. maybe litle bit helped that I used 1% tolerance metal film resisitors and also mached them for pairs.
BobElis- how can irf9610 to break down? if this happens on one board I can understand,maybe accidently, but if on all that shuold be somewhere problems. but I will try replace 9610 with soem unmached .I will let you know results, thanks again..
would you recomend to alchoholic relax and take a good sleep, while botle of vodka is near?
I dont drink, dont wach TV, I can only go to sport, to run, but after 30km I think my mind will not be clearer,because I dont have clear minds regarding amplifiers, theese are brutual, and "mood depend on" mashines with no mercy to poor people 
the only thing that goes to my mind is small resisitors. but what can be wrong with theese? and somehow I think(from expierence always fails transitors) that smth with tansistors.and the smaller transistor the evil minded it is.
seriuosly any inputs about whats is going on? can be irf9610 pins diferent from irfp240?
I dont drink, dont wach TV, I can only go to sport, to run, but after 30km I think my mind will not be clearer,because I dont have clear minds regarding amplifiers,
theese are brutual, and "mood depend on" mashines with no mercy to poor people the only thing that goes to my mind is small resisitors. but what can be wrong with theese? and somehow I think(from expierence always fails transitors) that smth with tansistors.and the smaller transistor the evil minded it is.
seriuosly any inputs about whats is going on? can be irf9610 pins diferent from irfp240?
is it posible to measure small resistors without soldering out? I also checked all 9 jumpers,but all contacts is firm. is it osible to test mosfet with multimeter,like in diode mode or smsth.like this?
theese bias L bias R and bias Q is setted up to zero position. I tried other positions but no luck..
theese bias L bias R and bias Q is setted up to zero position. I tried other positions but no luck..
yes I do some mistekes ,but BC550 was pain lessons(diferent manufacturers diferent pi out)few time so i learned lesson.. should I solder out resitors and measure, or should I desolder transitors and measure(like in maching process? there is so litlle components in this amp and I still cant find problems. I also checked soldering point but contact is OK, just in case I resoldered joints.
that was cool!
I checked all resistors and quess what- insted 100Kohm I soldered in 100ohm. how I did that? I carefuly mached resistors, BUT FORGET VALUES! i just put simply resistors back to pack paired. now I measured all left resitors in pack in both pack they are 100ohm. inspite on secon bag written100pieces 1% 100kohm!! is there any lawyers out there ? i think I will court my local shop fro things like theese. threy cut my life at least 5 years.
I turend on amp now for a few seconds and fets got hot , dc ofset reads 0,01v seems it should work.
I checked all resistors and quess what- insted 100Kohm I soldered in 100ohm. how I did that? I carefuly mached resistors, BUT FORGET VALUES! i just put simply resistors back to pack paired. now I measured all left resitors in pack in both pack they are 100ohm. inspite on secon bag written100pieces 1% 100kohm!! is there any lawyers out there ? i think I will court my local shop fro things like theese. threy cut my life at least 5 years.
I turend on amp now for a few seconds and fets got hot , dc ofset reads 0,01v seems it should work.
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