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Old 11-21-2017, 12:21 AM   #101
AresROC
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Default Re: Infinity PS-12 Powered Subwoofer Fired Amplifier

Yes, the power supply is an issue. The newer PS210 is rated 150w RMS, 210w "Average RMS", 300w "Marketing RMS" and 500w Peak dynamic, very generous ratings indeed with the same power supply as the PS-10/PS-12. PS210 have 2SK3594 MOSFETs instead of IRF640.

Attaching an external Class D Amp with this PS-12's power supply is just the last resort.

I also have a Behringer A500 Class A/B sitting around doing nothing... might be worth a try to see if the amp is a limiting factor to my dual subs reaching only 37Hz -3dB... It does do 25Hz -10dB with Audyssey.
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Old 11-27-2017, 02:54 PM   #102
AresROC
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Default Re: Infinity PS-12 Powered Subwoofer Fired Amplifier

The clipping noise returned... looking to replace the TIP-31C 15v power regulator transistor now... the fun never ends on this one!
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Old 01-25-2018, 02:07 PM   #103
imispgh
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Default Re: Infinity PS-12 Powered Subwoofer Fired Amplifier

budm you are the man!!!!!!!!!!! C37 was bad. Thank you
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Old 02-18-2018, 01:17 AM   #104
Jr_ece
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Default Re: Infinity PS-12 Powered Subwoofer Fired Amplifier

I have a 12" Infinity Entra Sub Two that appears to be the same sub with the same built in amplifier as the PS-12. I'll be pulling the amp out to inspect and replace components as required. Lots of good info here!
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Old 03-05-2018, 02:07 PM   #105
Jr_ece
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Default Re: Infinity PS-12 Powered Subwoofer Fired Amplifier

Really not seeing any bad caps other than the 2 large 3300uF caps. Ordered replacements for them. I might just purchase all of the cylindrical electrolytic caps like some have suggested here. I'm assuming that's what folks are referring to when recommending the replacement of all caps.

I'm thinking I will also replace Q3 and Q4 as suggested here. My amplifier doesn't appear to have the same issue with the blown cap on the back side. What is causing that to happen? Can I do something to prevent this damage?
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Old 03-05-2018, 02:25 PM   #106
Jr_ece
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Default Re: Infinity PS-12 Powered Subwoofer Fired Amplifier

Quote:
Originally Posted by AresROC View Post
Wow, got it pretty much figured out finally!

Replaced Q2 & Q3. Clean bass all day long! See my fixes here: http://zenlog.wordpress.com/2017/11/...-repair-ps-12/

One lingering issue remains. My right sub turns on to standby mode. Left sub turns on to ON mode right away. The service manual actually doesn't say which mode it should turn on to. Not a big issue...

Very tempting to upgrade this Amp from 150 watt to 250/500 watt
AresROC, you mentioned the following components in your blog. What reference designators are these parts replacing?

"TIP41C, IRF640NPBF, IRFB38N20DPBF, IRFB4227PBF"

Thanks!
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Old 03-19-2018, 08:01 PM   #107
Jr_ece
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Default Re: Infinity PS-12 Powered Subwoofer Fired Amplifier

Apparently I found a dead thread...

I haven't had much time to work on the PS-12, but I did add standoffs per a different forum with a small desk fan blowing into the opening to keep it cool.

I'm still planning to update/swap components when time allows.
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Old 04-16-2018, 12:55 PM   #108
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Default Re: Infinity PS-12 Powered Subwoofer Fired Amplifier

Quote:
Originally Posted by Jr_ece View Post
Apparently I found a dead thread...

I haven't had much time to work on the PS-12, but I did add standoffs per a different forum with a small desk fan blowing into the opening to keep it cool.

I'm still planning to update/swap components when time allows.
From what I can tell, IRF640NPBF is an exact replacement for IRF640N. So I'm going to guess that what AresROC did for 'upgrades' is:

Original -> New -> Location
TIP31C -> T1P41C -> Q4
IRF640N -> IRFB38N20DPB, IRFB4227PBF -> Q18, Q22

I'm further guessing that AresROC first used the IRFB38N20DPBF on one sub, then later the IRFB4227PBF on the other. IRFB4227PBF has higher specs than IRFB38N20DPBF. Both are rated higher than IRF640NPBF. I'll stick with the stock part and focus on airflow.

I didn't see that any specific transistors (Q2, Q3) were mentioned in the wordpress post or on this thread. I'm not sure if I will replace these, but I am planning to use:

Original -> New -> Location
MPSW06RLRA -> 610-CEN-U07 -> Q2
MPSW56RLRA -> 610-CEN-U57 -> Q3

I would have used 610-CEN-U06 and 610-CEN-U56 instead, but they aren't stocked anywhere I can buy them with the additional caps I'm buying. I plan on replacing the caps mentioned in this thread as they are old.

As an FYI, my sub doesn't put power out to the sub. No sound comes from the sub, but the auto signal detect appears working (LED switches color and switch connects). I have +15 and -15 rails working correctly (so I probably do not need to replace Q2 and Q3). I'll likely change them out anyway. The burn spot near the 2.4K 5W resistors (R6, R7A, R9, R9A) looks ok. I'm only using a cheap multi-meter to test, so I can't do much AC analysis. I hope there isn't a problem with the ICs. I hate removing ICs.
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Old 04-16-2018, 01:58 PM   #109
Jr_ece
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Default Re: Infinity PS-12 Powered Subwoofer Fired Amplifier

Jiari,
Thanks for the response and info!

I think I'll replace the transistors you listed in addition to the major caps.

I just quickly went through all 6 pages and found the following caps mentioned as candidates:

C2
C4
C6
C8
C9
C12
C35
C37
C65
C71
C72
C73
C78

There are a few that need to be evaluated for higher voltage and correct farad value depending on board revision.

I don't know if this covers "all" as mentioned in post such as #45 and #80 or not. It sounds like replacing this list of caps plus the transistors you clarified should fix just about any one of these subs. I would like to get an order together soon.

Last edited by Jr_ece; 04-16-2018 at 02:00 PM..
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Old 04-17-2018, 10:00 PM   #110
jiari
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Default Re: Infinity PS-12 Powered Subwoofer Fired Amplifier

Quote:
Originally Posted by Jr_ece View Post
Jiari,
Thanks for the response and info!

I think I'll replace the transistors you listed in addition to the major caps.

I just quickly went through all 6 pages and found the following caps mentioned as candidates:


There are a few that need to be evaluated for higher voltage and correct farad value depending on board revision.

I don't know if this covers "all" as mentioned in post such as #45 and #80 or not. It sounds like replacing this list of caps plus the transistors you clarified should fix just about any one of these subs. I would like to get an order together soon.
OOops. I should have checked actual board values before I ordered.

Before you go replacing parts, why not do some quick DMM tests? I was able to verify that one of my IRF640N's and the MPSW06RLRA was bad (even though I did have +15 and -15). Google testing of MOSFETs with a DMM for the IRF640N's and testing BJT. I did the testing on the board (which isn't ideal, but given the symmetric layout, I expected to get similar results for both pairs and did not get similar results). Therefore the tested item was either bad or had bad components around them. At least you'll have more confidence that replacing these parts will make an impact. I did these test with the amp unplugged for over an hour.

There are a multitude of things that can go wrong. Without a proper O-scope or some kind of probe+speaker setup, it's really hard to tell what's going wrong on the circuit.

Even if you replace everything everyone on this thread has, it's not a guarantee that an IC didn't crap out on you.

I plan on replacing everything, but leaving the IRF640N's and TIP31C off the board. I'm going to just probe the power supplies to make sure they are ok before even trying to install those parts. I would suggest you do the same. Find a convenient spot on the board to test the rails.

Also, I have an EE degree, though I haven't been one in over 10 years. I'm assuming you have some training as well. If you do not, please be extremely careful.
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