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Old 17th February 2013, 11:35 AM   #481
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Hi guys, new to the forums, signed up after trying to troubleshoot an issue with my pm66, took the case off and had a quick look at the pcb, looks like the 2 big caps have past their expiry date, leaking onto the board itself.

Can someone let me know if its pretty simple to replace? The amp powers up fine and plays but once in a while the right channel drops out. Hopefully replacing the caps will fix this.

Easy to source parts in the UK?
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Old 17th February 2013, 12:24 PM   #482
Mooly is offline Mooly  United Kingdom
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Large caps often often have "glue" to help secure them mechanically and if so it will be brown and probably a bit rubbery. True leakage (and it may well be that you have this) is often white and powdery.

If its just one channel dropping out then unlikely to be the caps. Check for poor joints, particularly on all the transistors and and components that run hot. Also the output relay (if it has one) can cause this effect and here the clue is that the fault clears if you turn up the volume.

Look at the last pictures in post #1 to see what typical dry joints look like.
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Old 17th February 2013, 03:32 PM   #483
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Hi Mooly, thanks for the tips. its more brown than white, but concerned since out off all the caps the 2 big ones look like they are about to pop. I take it just an age thing, will try and see if anyone local can maybe help take a look.

I got a few mods I want to do to my pm66se after reading this all inspiring thread, first is to fix the right channel drop outs at lower volumes, when the volume is set to 11 o'clock+ the problem doesn't really happen as often.

Would like to be able to use my custom kettle cables and fit better terminal connections. Time to hunt down a 2nd unit for the parts
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Old 17th February 2013, 07:37 PM   #484
Mooly is offline Mooly  United Kingdom
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The drop out being related to volume could be an indicator that the speaker relay contacts are tarnished, and if so it could be an easy fix, little more than popping the top off the relay and cleaning the contacts up with some paper soaked moistened with iso or even WD40.

Unless the caps are a known failure item across that model, then I would bet they are OK. Plastic tops on caps aften look a bit bulged.
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Old 17th February 2013, 07:40 PM   #485
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Cheers, will give it a quick clean and let you know how I get on.
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Old 17th February 2013, 07:41 PM   #486
Mooly is offline Mooly  United Kingdom
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Definitely worth a try
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Old 19th February 2013, 09:51 AM   #487
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Opened it up and did a quick clean, turns out it was the phono connections on the back. The CD one had obviously been used a lot more and seems tiny bit loose with the cable I had, currently got it connected to the AUX and its perfect, either way got the desired result thanks.
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Old 19th February 2013, 11:43 AM   #488
Mooly is offline Mooly  United Kingdom
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Excellent news. Thanks for the update.
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Old 3rd April 2013, 01:06 AM   #489
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Originally Posted by conker99 View Post
hi mooly.thanks again for your interest,i have a mate who is going to meter test and do the soldering if needed next friday,im just trying to get the bits i may need before hand, resistors are cheap so if its not that thats the problem its no loss financially,i jsu cant get my amp up and running quick enough !!!! i will look at r801 and r 803 also. thanks for your help.steve
after letting my mate look at the amp i didnt feel confident about him going further .is there anyone who knows what they r doing ,who can repair the amp for me ??
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Old 14th June 2013, 03:17 PM   #490
col996s is offline col996s  United Kingdom
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Hi. I am hoping to do the Bridge rectifier mod. I have some MBR20200CT diodes but I noticed on the data sheet it looks like there are two diodes in one package.
Do you just use one in each package?
Does anyone have information on how to do this please?
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