Aragon Amp 40mA offset
Sounds like the 40mA rail current difference isn't due to a prob with the output devices (typically they either open or short, not go half bad). i would guess its either the 100uf caps going bad (its a 10+ yr old amp, isn't it) or some other problem in the pre-drivers or front-end stage. from my recollection, the brochures described the amps as having only a single cap in the signal path (at input stage), so if there was a prob with drivers, it could possibly not show any DC offset at output, as the FB loop would null this out. also I thought brochures stated that their products used hand matched transistors throughout...
if anyone could send schematics (including both power amps and 18k pre), i could do some reverse engineering...
brucebw@pacbell.net
Sounds like the 40mA rail current difference isn't due to a prob with the output devices (typically they either open or short, not go half bad). i would guess its either the 100uf caps going bad (its a 10+ yr old amp, isn't it) or some other problem in the pre-drivers or front-end stage. from my recollection, the brochures described the amps as having only a single cap in the signal path (at input stage), so if there was a prob with drivers, it could possibly not show any DC offset at output, as the FB loop would null this out. also I thought brochures stated that their products used hand matched transistors throughout...
if anyone could send schematics (including both power amps and 18k pre), i could do some reverse engineering...
brucebw@pacbell.net
Aragon Amp 40mA offset, revisited
after mulling it over, i think the 40mA offset in rail current is normal. if the power LED has one side tied to ground that cound account for a 20mA difference alone. plus, the output muting board may have some ckts that draw from one rail only (like the muting relays).
-bruce
after mulling it over, i think the 40mA offset in rail current is normal. if the power LED has one side tied to ground that cound account for a 20mA difference alone. plus, the output muting board may have some ckts that draw from one rail only (like the muting relays).
-bruce
Sorry for the delay... Now frantically catching up...
Good catch, and you may be right-on regarding the LED (I'll have to dig up my pictures, but from memory I think it was drawing from the same channel. I do forget how the relay protection board was set up in all of it.
I did get a bit of info back from what's left of the Mondial support. Sad thing is that they only have partial schematics of the 8008 (nothing left of the 8002), and it's pretty much an illegible fax quality scan of it at that. But at least it was offered.
Board layout seems dead simple as it is, and a smart tech could easily figure things out by eye.
Definitely a fantastic amp. Can't say much about the sound, as it is has no distinguishing characteristics (just neutral). The speakers do all the talking.
If I ever feel boredom setting in, a cap change would be a good way to kill a lot of time (and hopefully not the amp). I don't remember seeing any input cap, only for the pre-drive PS. Will again take a look at my pictures to confirm...
Cheers,
bluesmoke
Good catch, and you may be right-on regarding the LED (I'll have to dig up my pictures, but from memory I think it was drawing from the same channel. I do forget how the relay protection board was set up in all of it.
I did get a bit of info back from what's left of the Mondial support. Sad thing is that they only have partial schematics of the 8008 (nothing left of the 8002), and it's pretty much an illegible fax quality scan of it at that. But at least it was offered.
Board layout seems dead simple as it is, and a smart tech could easily figure things out by eye.
Definitely a fantastic amp. Can't say much about the sound, as it is has no distinguishing characteristics (just neutral). The speakers do all the talking.
If I ever feel boredom setting in, a cap change would be a good way to kill a lot of time (and hopefully not the amp). I don't remember seeing any input cap, only for the pre-drive PS. Will again take a look at my pictures to confirm...
Cheers,
bluesmoke
Aragon 4004 Bias and DC offset adjust
Bias and DC offset adjust procedure
ARAGON 004 SERIES
BIAS & D.C. OFFSET ADJUSTMENT
1) PLACE VOLTMETER ACROSS ANY Of THE EMITTER RESISTORS. ADJUST BIAS ADJUSMeNT POTENTIOMETER FOR A READING OF lOmv +/- 2mv. REPEAT FOR THE OTHER CHANNEL.
2) SHORT THE INPUT, PLACE VOLTMETER ACROSS THE OUTPUT OF THE SHORTED CHANNEL. ADJUST D.C. OFFSET POTENTIOMETER FOR A READING OF O.OOvdc +/- .O1 V. REPEAT FOR THE OTHER CHANNEL.
3) ALLOW AMPLIFIER TO BURN IN FOR A MINIMUM OF 4 HOURS. THEN REMOVE SIGNAL AND ALLOW TO IDLE FOR 20 MINUTES. THEN REPEAT STEPS 2, THEN 1.
Bias and DC offset adjust procedure
ARAGON 004 SERIES
BIAS & D.C. OFFSET ADJUSTMENT
1) PLACE VOLTMETER ACROSS ANY Of THE EMITTER RESISTORS. ADJUST BIAS ADJUSMeNT POTENTIOMETER FOR A READING OF lOmv +/- 2mv. REPEAT FOR THE OTHER CHANNEL.
2) SHORT THE INPUT, PLACE VOLTMETER ACROSS THE OUTPUT OF THE SHORTED CHANNEL. ADJUST D.C. OFFSET POTENTIOMETER FOR A READING OF O.OOvdc +/- .O1 V. REPEAT FOR THE OTHER CHANNEL.
3) ALLOW AMPLIFIER TO BURN IN FOR A MINIMUM OF 4 HOURS. THEN REMOVE SIGNAL AND ALLOW TO IDLE FOR 20 MINUTES. THEN REPEAT STEPS 2, THEN 1.
Sorry for digging up an old thread.
I have just purchased a second hand Aragon 4004 mkII amp that was originally sold in the USA, it has supposed to be converted to 230vAC for my local Australian power requirements.
Can anyone help with a complete set of schematics, other than the already posted .pdf's for this amplifier. I want to check out the conversion and am wondering if there are any schematics for the power supply other than what looks like a hand drawn .pdf posted in this thread.
If possible could someone email me the schematics?
Thanks in advance for any help.
I have just purchased a second hand Aragon 4004 mkII amp that was originally sold in the USA, it has supposed to be converted to 230vAC for my local Australian power requirements.
Can anyone help with a complete set of schematics, other than the already posted .pdf's for this amplifier. I want to check out the conversion and am wondering if there are any schematics for the power supply other than what looks like a hand drawn .pdf posted in this thread.
If possible could someone email me the schematics?
Thanks in advance for any help.
Aragon 2004
Dear friend,
please send me for Aragon 2004 amp schematics in pdf files.
Regards,
Zeljko Bonacic Losic
Split
Croatia
P.S. My email is: bonaciczeljko@hotmail.com
Dear friend,
please send me for Aragon 2004 amp schematics in pdf files.
Regards,
Zeljko Bonacic Losic
Split
Croatia
P.S. My email is: bonaciczeljko@hotmail.com
Need resistors for 4004MKII
I just acquired a 4004 that was supposedly serviced 2 years ago (no way to confirm). Seems to work, but hollow mids, vocals are distorted (buzzy), highs seem OK, bass flat.
Opened it up, looked around, all I can see wrong is 2 resistors on the ground circuit board are corroded with covers cracked. Could this be it? If so, where can I get them to replace?
Lettering is Micro Ohm 10ohm 92-23, about 3/4 inch long, 1/4 inch wide barrels.
I'm not too skilled on electronic bench work for testing, but can easily replace the parts.
Thanks!
I just acquired a 4004 that was supposedly serviced 2 years ago (no way to confirm). Seems to work, but hollow mids, vocals are distorted (buzzy), highs seem OK, bass flat.
Opened it up, looked around, all I can see wrong is 2 resistors on the ground circuit board are corroded with covers cracked. Could this be it? If so, where can I get them to replace?
Lettering is Micro Ohm 10ohm 92-23, about 3/4 inch long, 1/4 inch wide barrels.
I'm not too skilled on electronic bench work for testing, but can easily replace the parts.
Thanks!
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