Hey all.
Does anyone out there have any inside pics of an untouched working Nakamichi PA-1004 ? or access to the amp to take pictures of it?
I'm in process of repairing mine, and a low res shot i dug up from ampguts shows what appears to be TO-220 package transistors where some TO-92 units that failed were in mine. Just wondering what is actually supposed to be in there.
If anyone can provide some inside shots or an original schematic I would greatly appreciate it.
Thanks!
~Aaron
Does anyone out there have any inside pics of an untouched working Nakamichi PA-1004 ? or access to the amp to take pictures of it?
I'm in process of repairing mine, and a low res shot i dug up from ampguts shows what appears to be TO-220 package transistors where some TO-92 units that failed were in mine. Just wondering what is actually supposed to be in there.
If anyone can provide some inside shots or an original schematic I would greatly appreciate it.
Thanks!
~Aaron
Interesting link Luke.
Looks like this person has done a complete site rip of - Ampguts -
I wonder if someone should let ampguts know ????????
Looks like this person has done a complete site rip of - Ampguts -
I wonder if someone should let ampguts know ????????
I used google images Luke... those aren't near high res enough... and yes, that looks like an exact rip of ampguts... for which I paid 10 dollars for a year membership to, and already saw all those images.
The PA-2004 is a different layout, but does still use the same PWM style supply, just a different physical configuration.
If you have any high res shots or can take some of the area near the small pulse transformer in the PA2004 (a 1004 is ideal, but i'm not picky at this point) I'd be interested...
EDIT: Also some high res shots of the area around the two IC's (324 and 494) as those are part of the controller circuit for the PSU.
The PA-2004 is a different layout, but does still use the same PWM style supply, just a different physical configuration.
If you have any high res shots or can take some of the area near the small pulse transformer in the PA2004 (a 1004 is ideal, but i'm not picky at this point) I'd be interested...
EDIT: Also some high res shots of the area around the two IC's (324 and 494) as those are part of the controller circuit for the PSU.
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http://www.bcae1.com/temp/IMG_5062.JPG
http://www.bcae1.com/temp/IMG_5068.JPG
If you view them at 100% resolution, they should be good enough.
http://www.bcae1.com/temp/IMG_5068.JPG
If you view them at 100% resolution, they should be good enough.
@Luke. - well, when you're desperate to try and see the color bands on a fried resistor in your amp and have no access to original schematics, yes, people will pay for stuff like this. The way I see it, I paid 10 dollars for an entire year access to a site with pics of insides of amps. The costs of hosting a website are much more expensive than 10 bucks.
@PB - you are officially the man! Do you own that amp? If so can you check the part numbers on the two transistors Q14 and Q15 (in circuit with the 494). They look like TO-92L package KTA1023 units like what was in mine. Those pics did confirm that the resistors across base-emitter and series base resistors between the 494 and Q14, 15 are the same as the 1004.
Interesting fact. I have been in contact with Stephen Mantz who designed these, and he tells me that they have changed the values of these resistors over the years. Apparently the base-emitter resistors should be between 10 and 15 ohms, and the series base resistors should be less than 2.7ohms if using KTA1023 units. That's straight from the horses mouth so to speak.
According to UPS my replacement transistors should be here later today. I'm really hoping this fixes it. I have the new "updated" value resistors as well. I intend on reassembling with the original values in there first. And if it powers up smoothly grabbing a scope trace. Then swapping the resistors out and grabbing a second scope trace to compare.
Thanks again for posting the pics! I really appreciate it.
-Aaron
@PB - you are officially the man! Do you own that amp? If so can you check the part numbers on the two transistors Q14 and Q15 (in circuit with the 494). They look like TO-92L package KTA1023 units like what was in mine. Those pics did confirm that the resistors across base-emitter and series base resistors between the 494 and Q14, 15 are the same as the 1004.
Interesting fact. I have been in contact with Stephen Mantz who designed these, and he tells me that they have changed the values of these resistors over the years. Apparently the base-emitter resistors should be between 10 and 15 ohms, and the series base resistors should be less than 2.7ohms if using KTA1023 units. That's straight from the horses mouth so to speak.
According to UPS my replacement transistors should be here later today. I'm really hoping this fixes it. I have the new "updated" value resistors as well. I intend on reassembling with the original values in there first. And if it powers up smoothly grabbing a scope trace. Then swapping the resistors out and grabbing a second scope trace to compare.
Thanks again for posting the pics! I really appreciate it.
-Aaron
I don't have the amp. In the photos I have, you can just read the 23 on the end of the part number so they are very likely 1023s.
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