RCF ART315A Protect mode

[paleeman]

You are very welcome. I am happy that you have repaired your speaker.

BTW Thanks for the beers! (bring some portuguese wine too )

[Ghost_Bass]

Today it's hanging on fine for the past couple of hours.

[jijone]

Sorry Marco. I owe you an apology. I had no intention to confuse you. As I was reading your reply, I came to the conclusion, that you probably have the older version, with the base amp board and the filter card. If that is the case, I suggest you to replace the capacitor marked C52, value 10uF/16V.

Good luck

[ATTACH=CONFIG]28150[/ATTACH]

i have to give u a lot of bear too ,
same problem , fix it as u said
ty so much

[diydidi]

I don't see C52 on the schematic. Where is it, what does it do??

[g1]

Look at the second page of ART315A Bass Amp.pdf, upper left area, at pin2 of U15A. It is part of the fault/mute circuitry.

[diydidi]

Got it!!

[paleeman]

jijone
Awesome!

diydidi
It is a part of the MUTE circuitry.

[paleeman]

G-one, beat me to it

[jijone]

hello paleeman
i got a new problem with my rcf 312 a , is dead
i want to change mmbta 42 and 92 but i cant identify them. i have the schematic from 315a but cant find the transistors.
any advice?
thanks in advance

[Enzo]

Aren't those just surface mount versions of MPSA42 and 92?

[jijone]

hello paleeman
i got a new problem with my rcf 312 a , is dead
i want to change mmbta 42 and 92 but i cant identify them. i have the schematic from 315a but cant find the transistors.
any advice?
thanks in advance

[Ghost_Bass]

Sorry Marco. I owe you an apology. I had no intention to confuse you. As I was reading your reply, I came to the conclusion, that you probably have the older version, with the base amp board and the filter card. If that is the case, I suggest you to replace the capacitor marked C52, value 10uF/16V.

Good luck

[ATTACH=CONFIG]28150[/ATTACH]

Well... after a bit more than a year of perfect functioning my ART 312A MKII developed the same problem. I went in there and replaced the capacitor again and it worked for only about 2 min before entering protect mode. Tried another capacitor just to ensure i hadn't soldered a faulty one and the problem remains.

What do you think? Is it time to bin this (make it a passive floor monitor of course) and get a new/used one?

just a thought, is there a way to remove the protection circuit? We use a pair of these so if the other one goes in to protection we obvioulsly will turn off both and prevent this one from burning.

I'm up for anything, the extra year i got from this speaker by replacing the cap was enough to justify the money that we'll spend on a new one but i'll try other ideas before making it passive.

Last idea, anyone know where i can buy a complete power amp module for this model? I don't mind if it's used or repaired as long as it's working as it should. I searched the web and can't find anyone stocking these and RCF's distribuitor quoted me for a bit over 300€ for a new module...!!! i can find used 312A's on e-bay for way less money!

Cheers
Marco

[Jazz P Bass]

Quote:" just a thought, is there a way to remove the protection circuit?"

It's there for a reason.

I would not go there.

[Ghost_Bass]

Quote:" just a thought, is there a way to remove the protection circuit?"

It's there for a reason.

I would not go there.

Yes, i know, it's there to save it from peaks and other stuff but i feel bad knowing i have a perfectly functional power amp and it doesn't work because of something on the protection circuit. It would be a shame to bin the module but i can't find a fix and RCF doesn't sell the PCB's alone, only the whole module.

[52 Bill]

just a thought, is there a way to remove the protection circuit? We use a pair of these so if the other one goes in to protection we obvioulsly will turn off both and prevent this one from burning.

It does not work that way. The protection circuit is there to protect the speakers from being damaged when the power amp fails. If the power amp in one speaker fails and goes into protect mode, the other amp will continue to work.

There are a number of reasons for the protect circuit to trigger. The fact that you had a bad cap earlier does not mean that you have one now. You may have a small amount of dc voltage on the speaker output buss, or there is a different part that has gone bad. The only way to know is to test the circuit parts and figure it out.