Infinity PS-12 Powered Subwoofer Fired Amplifier

[jiari]

Re: Infinity PS-12 Powered Subwoofer Fired Amplifier

It's alive.

1st try (still dead): I started by replacing everything except C72 and C73 because, why not. Same problem (no output even though relay clicks and I can verify the relay is working). I verified the rails and they looked about the same (I think one leg was low by a volt). One of the 15V diodes is probably going.

2nd try (worked): replaced C72 and C73. Output seems to work fine. I got this broken off Craigslist for $35, spent another $30 in parts. I don't know what it sounded like before. Compared to my 8 inch 100W sub, this "300W" sub doesn't seem that much louder at 75% volume, though it is a lot punchy-er (ie you feel the low frequency much more). It could also be the setup. The 8 inch is in the corner and the PS-12 is infront of the TV.

I added 3/8 inch standoffs, but the indent of the sub enclosure still blocks any proper airflow. I'll need a fan.

In my setup, the power strip turns on the sub when the tv comes on, which is annoying now as the sub always chirps when it starts up. I checked and it's apparently normal, which makes some sense.

[jiari]

Re: Infinity PS-12 Powered Subwoofer Fired Amplifier

jiari, I basically ordered the same parts. Should be here in a few days. Then find time to install...

Yep, it's always finding the time that's the problem. I'm still looking for mine.

[Jr_ece]

Re: Infinity PS-12 Powered Subwoofer Fired Amplifier

jiari, I basically ordered the same parts. Should be here in a few days. Then find time to install...

[Jr_ece]

Re: Infinity PS-12 Powered Subwoofer Fired Amplifier

I just took a quick glance at the service manuals for the 2 subs (Entra Sub Two, PS-12), and they are basically identical with the exception of just a few parts removed. Outside of the few missing, it appears all of the part numbers are exactly same. Sorry for the confusion last night!

[Jr_ece]

Re: Infinity PS-12 Powered Subwoofer Fired Amplifier

Well duh. In one of my more recent posts I referred to my sub as PS-12. That wasn't actually correct. They are so close I just picked up that label for it. Mine is the Entra Sub Two. The service manual for it is Rev 1 4/2003.

I pulled down the PS-12 Rev 1 10/2004 service manual just to have it.

[Jr_ece]

Re: Infinity PS-12 Powered Subwoofer Fired Amplifier

Interesting. I wonder what else changed between manuals. I'll have to look, but I think mine might 2002 or 2003.

Guess I made a good choice on those 2 caps.

[jiari]

Re: Infinity PS-12 Powered Subwoofer Fired Amplifier

I decided against replacing C17 and C18 due to their use/location.

Huh. My service manual (Rev 1 10/2004) doesn't have a reference to C17, C18. And my board has both of those spots blank.

[Jr_ece]

Re: Infinity PS-12 Powered Subwoofer Fired Amplifier

I decided against replacing C17 and C18 due to their use/location.

[Jr_ece]

Re: Infinity PS-12 Powered Subwoofer Fired Amplifier

I ordered 2 film capacitors to replace the non-polarized. You'll notice I ordered a 10% film vs the 5% film you linked. A quick web search and it looks like the original part was 10%. I doubt it makes a difference. I'm pretty sure I just decided to save the 28 cents. It was cheaper to go film than to order NPE's off another site due to shipping costs.

I didn't notice any 200uF NPE capacitors in the BOM. Maybe you are referring to the polarized 220uF or 22uF?

Thanks for the parts list! Very helpful.

My PS-12 has 200uF/5V NP cap at C17 and C18.

The PS-12 service manual BOM has the following:
033-200645-300 NP Capacitor 200u/50V M (R)1321 P:5 2 C17,18

I didn't find a 200uF NP cap on mouser, but did find a 220uF NP.

[jiari]

Re: Infinity PS-12 Powered Subwoofer Fired Amplifier

Found this posted by budm (2012). The link still works but it appears to be polarized instead of non-polarized unless the product changed. A few posts earlier budm mentioned replacing the 6.8uF NP with a 6.8uF film cap from Parts-Express.

Mouser.com has a 10uF 100V NP cap, but it doesn't appear anyone here came to the conclusion that a 10uF was a suitable replacement for the 6.8uF or not.

Any thoughts on a 6.8uF 100V NP replacement?

If you want to spend the money, here are the proper parts from parts-express:

https://www.parts-express.com/68uf-1...citor--027-336
https://www.parts-express.com/47uf-1...citor--027-332

[jiari]

Re: Infinity PS-12 Powered Subwoofer Fired Amplifier

I ordered 2 film capacitors to replace the non-polarized. You'll notice I ordered a 10% film vs the 5% film you linked. A quick web search and it looks like the original part was 10%. I doubt it makes a difference. I'm pretty sure I just decided to save the 28 cents. It was cheaper to go film than to order NPE's off another site due to shipping costs.

I didn't notice any 200uF NPE capacitors in the BOM. Maybe you are referring to the polarized 220uF or 22uF?

I would change like for like whenever possible. The only reason I changed anything was due to product availability.

I actually ordered from Mouser (part numbers below use Mouser #'s). I'm assuming from previous posts you can tell where everything should go on the board. Here's my order (quantity in parenthesis) [Description; board references]:


(2) 942-IRF640NPBF [MOSFET; Q18, Q22]
(1) 610-CEN-U07 [BJT NPN; Q2]
(1) 610-CEN-U57 [BJT PNP; Q3]
(1) 863-TIP31CG [BJT Bipolar, Q4]
(2) 647-UVY2A332MRD [100V 3300uF; C6,C8]
(1) 647-ULD1H4R7MDD1TD [50V 4.7uF; C2]
(2) 647-USV1E220MFD1TE [25V 22uF; C4, C9]
(1) 647-UVZ1C331MPD1TD [16V 330uF; C12]
(1) 647-UVY1C221MED1TD [16V 220uF; C37]
(1) 647-UPW1E100MDD1TD [25V 10uF; C35]
(1) 667-ECQ-E1475KF [film capacitor 100VDC 4.7uF; C73]
(1) 667-ECQ-E1685KF [film capacitor 100VDC 6.8uF; C72]
(10) 749-9911-312 [.312 standoffs, nylon]

[Jr_ece]

Re: Infinity PS-12 Powered Subwoofer Fired Amplifier

Looks like I can get a 6.8uF 100V film radial (versus axial) capacitor if the leads will match up. Seems like it should work.

https://www.mouser.com/ProductDetail...DeWz7%252bw%3d

[Jr_ece]

Re: Infinity PS-12 Powered Subwoofer Fired Amplifier

http://www.parts-express.com/pe/show...umber=020-1429

This one does not fit?
there are two caps, one is 4.7 and another one is 6.8

Found this posted by budm (2012). The link still works but it appears to be polarized instead of non-polarized unless the product changed. A few posts earlier budm mentioned replacing the 6.8uF NP with a 6.8uF film cap from Parts-Express.

Mouser.com has a 10uF 100V NP cap, but it doesn't appear anyone here came to the conclusion that a 10uF was a suitable replacement for the 6.8uF or not.

Any thoughts on a 6.8uF 100V NP replacement?

[Jr_ece]

Re: Infinity PS-12 Powered Subwoofer Fired Amplifier

The noise could be a problem. I'll have to watch for that. Thanks for mentioning it.

Are you swapping out the non-polarized caps (6.8uF, 4.7uF, 200uF x 2) as well? The only source I'm finding for the 6.8uF is a Parts-Express branded cap. Amazon sells it for about $6. The price appears to have shipping baked in (compared to direct from Parts-Express).

I'm planning to order everything except the 6.8uF NP cap (only finding 50V cap and not a 100V cap) from mouser.com since there shipping tends to be a bit lower for me.

Did you go with the original transistors and MOSFETS or to the new part numbers we discussed above?

[jiari]

Re: Infinity PS-12 Powered Subwoofer Fired Amplifier

You are probably correct about the transistors and MOSFETS. I guess I could always pop the amp back out if I want to change them later... just thinking of buying them while I have an order/shipping.

I looked back at some of the posts around DoubleD14, and I think you are right about the Auto On/Off caps. Someone soon after DoubleD14 ended up replacing 7 or 8 caps and it fixed similar issues. I might shrink my list to those caps first, and stick with the original transistors/MOSFETS.

After all of that I plan to add active cooling inside the amp space. I've checked the available space and it looks like I can add a 12vdc supply (tab off 110vac), a quiet 50mm fan, and external temperature probe/monitor to kick the fan on/off. The thought is to mount the temperature probe CCA/case on the back of the sub with the 12vdc coming out and temperature probe going into the vicinity of the 5W resistors. Looks like about $27 for active cooling.

For the price, I think you're only spending another $10 or so for the Transistors + MOSFETs + extra Caps. Might as well lump them in. For me, that was the cost of shipping, so cheap insurance if I have to buy again.

I'd be cautious of putting a 110AC to 12VDC converter in there. I believe you're looking at getting one of the small switching power supplies. They can couple in noise depending on placement and the box is pretty small. Probably more of a concern is if you have to run the 110AC 60Hz around the board to where you mount the 12VDC converter. With the high power, there's definitely a higher chance of coupling in noise you don't want. Someone else may know better, I'm just pointing it out.

My plan to avoid that is to mount a 50mm 5VDC external fan. I am going to cut out a spot (below the RCA inputs) and mount a fan on the outside of the case (but within the indented portion of the plastic). I have spare USB cables from a bad keyboard and a few low power USB wall chargers. I am already planning to use 3/8 standoffs all around and with the fan blowing air in, it should be pretty efficient. My TV and receiver turn on all other devices, so I'm not worried about leaving the sub and usb fan on.

[Jr_ece]

Re: Infinity PS-12 Powered Subwoofer Fired Amplifier

Replacing caps due to expected aging makes sense. I'm still not 100% convinced that the transistors and MOSFETs are going to go bad unless something else fried them, but since the board is open, it's a low cost change. I'm planning to replace almost all the same components myself. For me, I'm worried about ESD damage to the new parts due to having a poor space to solder (random fold up table setup in the garage). I already removed all the parts I'm replacing, but haven't found time to put in the new parts.

It sounds like all of your issues are related to the Auto On/Off. I think that's the same problem that DoubleD14 had.

I'm hoping to put in the new parts sometime this week. I'll report back if it worked.

You are probably correct about the transistors and MOSFETS. I guess I could always pop the amp back out if I want to change them later... just thinking of buying them while I have an order/shipping.

I looked back at some of the posts around DoubleD14, and I think you are right about the Auto On/Off caps. Someone soon after DoubleD14 ended up replacing 7 or 8 caps and it fixed similar issues. I might shrink my list to those caps first, and stick with the original transistors/MOSFETS.

After all of that I plan to add active cooling inside the amp space. I've checked the available space and it looks like I can add a 12vdc supply (tab off 110vac), a quiet 50mm fan, and external temperature probe/monitor to kick the fan on/off. The thought is to mount the temperature probe CCA/case on the back of the sub with the 12vdc coming out and temperature probe going into the vicinity of the 5W resistors. Looks like about $27 for active cooling.

[jiari]

Re: Infinity PS-12 Powered Subwoofer Fired Amplifier

All good points.

My thought behind replacing the major electrolytic caps is due to the heat exposure they've had from lack of proper cooling. Aging or complete cap failure can cause a handful of things to occur. My sub has 2 or 3 issues that I think replacing caps will fix.

1) The squeal on power up issue. This one seems pretty cut and dry.
2) The sub will not come out of standby until volume is turned up to at least moderate levels if not quite loud.
3) The sub will go back to standby if volume is reduced to something less than moderate levels. With music it tends to stay engaged. With movies the sub can be heard squealing out of standby mode when an action scene or intense music elevates the volume. Annoying.

The thought behind replacing the transistors is to see if perhaps they are also performing sub par from heat or aging, and new ones might tighten the bass a bit. This seems to be the benefit based on AresROC's blog and forum posts. Am I misreading this information or is it something else that could contribute to softer bass?

Replacing caps due to expected aging makes sense. I'm still not 100% convinced that the transistors and MOSFETs are going to go bad unless something else fried them, but since the board is open, it's a low cost change. I'm planning to replace almost all the same components myself. For me, I'm worried about ESD damage to the new parts due to having a poor space to solder (random fold up table setup in the garage). I already removed all the parts I'm replacing, but haven't found time to put in the new parts.

It sounds like all of your issues are related to the Auto On/Off. I think that's the same problem that DoubleD14 had.

I'm hoping to put in the new parts sometime this week. I'll report back if it worked.

[Jr_ece]

Re: Infinity PS-12 Powered Subwoofer Fired Amplifier

All good points.

My thought behind replacing the major electrolytic caps is due to the heat exposure they've had from lack of proper cooling. Aging or complete cap failure can cause a handful of things to occur. My sub has 2 or 3 issues that I think replacing caps will fix.

1) The squeal on power up issue. This one seems pretty cut and dry.
2) The sub will not come out of standby until volume is turned up to at least moderate levels if not quite loud.
3) The sub will go back to standby if volume is reduced to something less than moderate levels. With music it tends to stay engaged. With movies the sub can be heard squealing out of standby mode when an action scene or intense music elevates the volume. Annoying.

The thought behind replacing the transistors is to see if perhaps they are also performing sub par from heat or aging, and new ones might tighten the bass a bit. This seems to be the benefit based on AresROC's blog and forum posts. Am I misreading this information or is it something else that could contribute to softer bass?

[jiari]

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:


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.

[Jr_ece]

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.