I have a friend wants me to repair a dead 527 API compressor. Hoping it’s a bad 2520 but just Incase. Does anyone have a schematic? Or schematic 2500 which I think uses the same circuit in a rack mount as opposed to 550 module. Thanks!
API527 schematic repair
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pucho812
Well-known member
sadly I don't think anyone has that action. I tried to get a 2500 schematic in the past but was not allowed from API. the most common issue is a dead 2520. they are designed to fail, not if but when. replace accordingly according to API. if you really want to, stick in a red dot to avoid having to do it again.
![[silent:arts]](https://cdn.imagearchive.com/groupdiy/data/avatars/m/0/172.jpg?1620371656){kind=avatar}
[silent:arts]
Well-known member
I don't have schematics but the last API product I repaired had a cold solder joint.
It already had an external 3rd party PSU (it was a Rack unit) and all 2520s replaced ...
It already had an external 3rd party PSU (it was a Rack unit) and all 2520s replaced ...
I just got them and suspect a dead 2520. I ask my friend if it is a bad 2520 , I would replace in both units (one works one doesn't) with a red dot or something to keep them sounding similar as a stereo pair. I'll get to these in a day or two and report back.
Thanks guys.
Thanks guys.
pucho812
Well-known member
well you have one working and one not working. Easy enough to swap between the two and see if there is a change. 8)
pucho812
Well-known member
fazer said:Bad 2520 output. Replaced and working.
well done 8)
pucho812 said:
Hi Pucho, I had a lot of 2520 units falling back in the day in the studio I worked in.
What if the reason for so much 2520 fails? why are they designed to fail from a technical point of view?
This might be more for the Brewery but opamps were originally potted to hide their secrets. Some claimed it was for thermal reasons. Now there is so much myth about them that they can't NOT pot their opamps. If someone opened an API factory unit and saw a flat pcb with discrete components in place of the black box they would reject it. The fact that they have sockets means that they expect them to fail at some point and be replaced. But they won't say that out loud and they act surprised when you say you have seen a lot of opamp failures. Everything I service that is not under API warranty gets a GAR2520.
pucho812
Well-known member
Whoops said:
What Señor Jippie said. I can go into some personal theories about how potting them makes it worse for thermal dissipation then non potted and such but no worries. I am with mrjippie, I just replace them with another 2530 variation, I like the Scott liber ones but any will really do. The bugger is how API is so secret with their opamps, they really don't like to sell them unless you send them a bad one.
I heard from an EX API employee how you can use chemicals to un-pot the 2520 but to the life of me I can't remember what it was, perhaps it's because the process was harmful to breath in...
Thanks for the confirmation. By the way it is Rippe, Michael Joseph - but folks call me Mike ;D
pucho812
Well-known member
mjrippe said:
Sorry was autocorrected. Cheers buddy
[silent:arts]
Well-known member
If you want to see one naked:pucho812 said:
https://www.instagram.com/p/BxQIjpGBVlz/
pucho812
Well-known member
[silent:arts] said:
you know there are folks who claim the thru hole versions sound better then thew SMT versions :
Thats cool thanks.
Garys 2520's sound good to me for replacement. It would be nice to compare 2520 schematics to api current release. I look at the photos and think about red dots being much the same construction. Looks like old school output transistors to keep the profile low but other than that they are very much like Scott Libers surface mount.
