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Sub-10 / Sub-12 / RPW-10 Repair Blog


ngen33r

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I have given up on trying to fix RT-10D  this and would like someone with more knowledge, experience and patience to fix it as I am not the one!(very humbled!).
Anyone out here who would fix the ps board (definitely blown and attempts have been made to fix it), and test/fix if needed the amp part of it which has remained untouched.

I am fixing it as a favor to the local police officer so please be kind here with prices/estimates. I am good at soldering, basic troubleshooting but not-so-good at analog 🙂

 

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  • 2 weeks later...

Hi, thanks for your posts. I really appreciate the education and tips!

 

I'm working on this SUB-10 and after cleaning the large blob of glue from the corner of the board, I notice that there are a couple of SMD resistors missing from the board. Looking at my original picture, I see that R115 was not there when I began but R127 was buried under the glue. My question is whether there was a resistor on R127 that I possibly removed while cleaning the glue? If so, can you tell me the value?

 

Also, I've recapped the board and replaced Q11, D11, and D12 on the PDC. I have not updated Q5 or replaced anything else yet.  I'm getting about 24V across the regulators but only about .5V across the big resistors.

 

Any guidance will be greatly appreciated!

 

UPDATE: I updated Q5 and now have 5.3V where it's supposed to be! I'm going to assume that the missing resistor is not a problem. There are several blank spaces on the board so if it works, don't fix it!  I'll be testing signal and bias tonight but it is looking better.

20210204_204340-1.jpg

20210112_175731-1.jpg

Edited by mkeogh
Reg voltage was lower than what I remembered when I wrote the post
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I think you repaired my dead sub many (~7) years ago.  Part of the repair was to add a fan to help cool it.  Now, when I start it up after it has been off for a while, the fan squeals for a bit, then stops.  I thought I would ask you before I tore into it: what kind of fan did you put into the sub for cooling?  It is something I can easily replace?  Do I need any special tools.  Unfortunately, I tossed all the old emails, so I could not ask you directly.

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On 2/15/2021 at 8:35 PM, dashman said:

I think you repaired my dead sub many (~7) years ago.  Part of the repair was to add a fan to help cool it.  Now, when I start it up after it has been off for a while, the fan squeals for a bit, then stops.  I thought I would ask you before I tore into it: what kind of fan did you put into the sub for cooling?  It is something I can easily replace?  Do I need any special tools.  Unfortunately, I tossed all the old emails, so I could not ask you directly.


I never added fans to any repair. That is a hack and not the proper way to do it. I assume you have a ProMedia 5.1?

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I have a sub 10 power board that's stopped working. After careful visual inspection I didn't find any burned components. Following your initial voltage testing procedure it has the 97V on the big cap, the 25V across the two 15V voltage regulators' tabs, the +-15V are present, but I didn't get the ~5V across the two 150-ohm resistors. What's that telling me? Where to check next?

 

Thank,

Peter

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On 2/20/2021 at 2:50 AM, ngen33r said:


I never added fans to any repair. That is a hack and not the proper way to do it. I assume you have a ProMedia 5.1?

Just wondering, why do you call it a hack?  The reason the fan was add was to promote cooling because it was overheating inside.  What would you do to fix the amp that burned out due to overheating?  Granted, I had the amp for about 10 years at the time it stopped working.  And yes, it is the PM 5.1.

Edited by dashman
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Hi, I have a sub 10 which seems to be working fine, but what I noticed on my amplifier (Yamaha RX-v810) was the right channel regularly dropping for some reason, after doubting the amp and the speaker, I decided to disconnect the cinch cable from the sub out on the amp to the line in of the sub since I also noticed some power leakage (serious static feeling on the cable) and TADA, the amp is working like it should! When I now turn the sub on and feel the cinch cable, I still feel the power leakage. I didn't open the sub yet, I first wanted to know the opinion of an expert. Since the sub still nicely turns on and hums if I touch the inner connection of the cinch cable, I assumed the sub is still ok, but it seems to be defective...

 

Ow I almost forgot, nothing is grounded (the sub has no ground connection anyhow), the house we are currently living in is not ours so I cannot do anything about that except maybe for using the radiator as a ground source..

 

Thank you in advance for your opinion! 

 

Richard

Edited by riochicken@gmail.com
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On 2/22/2021 at 7:34 PM, dashman said:

Just wondering, why do you call it a hack?  The reason the fan was add was to promote cooling because it was overheating inside.  What would you do to fix the amp that burned out due to overheating?  Granted, I had the amp for about 10 years at the time it stopped working.  And yes, it is the PM 5.1.

It is a hack, because it masks the problem. It does not correct the problem. Plus that fan just circulates the hot air inside so it is not all that effective. The correct repair is to remote mount the control circuit and get it out of that that power supply that is packed too tight.

But this is off topic for this thread.

 

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On 2/26/2021 at 1:25 AM, riochicken@gmail.com said:

Hi, I have a sub 10 which seems to be working fine, but what I noticed on my amplifier (Yamaha RX-v810) was the right channel regularly dropping for some reason, after doubting the amp and the speaker, I decided to disconnect the cinch cable from the sub out on the amp to the line in of the sub since I also noticed some power leakage (serious static feeling on the cable) and TADA, the amp is working like it should! When I now turn the sub on and feel the cinch cable, I still feel the power leakage. I didn't open the sub yet, I first wanted to know the opinion of an expert. Since the sub still nicely turns on and hums if I touch the inner connection of the cinch cable, I assumed the sub is still ok, but it seems to be defective...

 

Ow I almost forgot, nothing is grounded (the sub has no ground connection anyhow), the house we are currently living in is not ours so I cannot do anything about that except maybe for using the radiator as a ground source..

 

Thank you in advance for your opinion! 

 

Richard



Could be a bad bypass cap inside the amp. It should not have any high voltage leakage to the inputs.

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Hello ngen33r, I am posting here in your thread to hopefully get some help.  I have a Sub-10 that worked great for years and then no longer was working...I leave the switch in the "auto on" position then turn off the Main Stereo Amp.  The system is in my Theater room in the Basement and after my son took over I didn't venture down there too often. Well after some years, a potential bunny rabbit (long story) nibbIing on the power cord and finally a cover falling down on the connector cable (all of this could be coincidence) the AMP no longer worked and the fuse was blown. I replaced the fuse (just to see) and yes - it blew again. So off to the races.

 

I removed the plate amp, but I did not see anything obvious and didn't smell anything in regards to blown components in the power supply.  A Google search brought me to this thread. So I disassembled the unit and found the following:

1) The THC (thermistor) looked funny but still read around 10ohms

2) The glue on C72 softened and looked crispy. I think it also got on the PDC board (or something did) and potentially caused a short near Z1

3) I tested Q3 and Q4 and one was good and one was bad.

 

Sooo, before going further, I wanted to review my plan of attack with you...

 

1) PDC Rebuild

     replace Z1 & Z2

     replace Q11 with MPSA92

     (I didn't think the resistors could be bad or the DIAC since if I read your PDC schematic right R1 & R4 tie (go) to the DIAC (D11) and since 1 FET was still good I guess

       D11 & D12 are good, but I am questioning R1, R2 & R3. These 3 resistors are in the circuit with Z1 where the bad spot on the board was)

 

2) PS Rebuild

     Replace IRF730 (I have 730's)

     Replace C58 470uF cap 

     Replace C27 & (what every the number of the second one is) with panasonic caps (WFA2J 104JE7)

     Replace TH3 with 10ohm 5A (STM CL-60) This I am a little apprehensive since The original is 10hm 4Amp (160WATTS) and the other is 250WATTS 

 

3) BASH Board

     Replace Q5 with 2N4401

 

I'm including a couple PICS to help.   Let me know what you think.  Thanks for you help.

 

 

20210307_141602.jpg

20210306_223314.jpg

20210306_223306.jpg

20210306_222954.jpg

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  • 2 weeks later...
On 3/23/2021 at 3:59 PM, ngen33r said:

You tore out one of the thru-holes on the PDC. That should be repaired. You are also missing a gate drive resistor and there is a good chance the DIAC is blown. The ICL should not matter much between 4A and 5A. 

ngen33r, you are alive.

 

Yes, I noticed Pin4 on the PDC and need to fix that. I ordered SMD R49 from Mouser along with a couple other parts. I fully tested the PDC and found all parts to meet spec.. image.png.628bdfa2a2cb2e144eaf028648c5a49f.png

Here's a table. I did replace Q11 anyway. If you look at Diodes, do they look ok? The DIAC didn't read a breakdown voltage so you maybe right. The only thing with the PDC board is that only 1 MosFet was blown Q3 along with the Gate resistor (melt'd) R49. Leads me to believe the DIAC maybe ok.

 

So, right now, I plan to:

1) replace the Mosfets Q3/Q4 - done and trace repaired.  Continuity verified

2) replace R49 - done

3) replace (update) Q5 - done

4) re-cap the board - done

5) replace TH3 - done

 

20210308_214949.jpg

Edited by The_Tinkerer
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i am alive, just been very busy with a contracted job. I plan to get back to making videos now that I am done with that. It is confirmed that there are 2 versions of the PDC and some parts will not match my schematic. I will post that info. Since it has been verified. Looks good otherwise.

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