Sherbourn, Bad Caps? Newbie needs help

HifiGuy84 · 3rd January 2010, 02:28 AM

Hello everyone,

I work in the sales and system design end of the A/V industry, but am extremely new to most of the actual repair and workings of two amplifiers I own. I have a 5ch. and a 2ch. Sherbourn amplifier 5/1500A. The chassis are the same and are of a modular card design. Each channel has its own card and transformer. In at least two channels on the five channel and one channel on the two channel I am have the same issues. There is crackling and sometimes the channel won't work at all. From what I am reading, this could potentially be a problem with the caps going bad. Is this the case? The amplifiers are 12-13 years old. I have never done any major repair like this in the past, but am interested in the undertaking. If it is indeed the caps going bad, what should I replace them with? I would like to replace them all at once so the amp continues to work down the road and the channels are matched. I am not sure if the caps may have any bearing on the overall tonality of the amps, but if I could I would warm them up a bit. For my taste, they are too analytical with my Monitor Audio GS60's. What tools and parts would I need and can I do this as a newbie? Any other parts I should replace at the same time? Any other advice would be appreciated.

Best regards

Britton

HifiGuy84 · 5th January 2010, 12:34 AM

Maybe a list would be easier since no one has responded.

Problems:

Channels on two different amps I own are starting to go. Sometimes they just do not work other times they scratch and hiss. These are stand alone amps on different systems both same make model and age.
I am new at this, but familiar with things on a conceptual level.

Thoughts:

From things I have read these problem could be as a result of the caps going bad.

Goals:

Fix amplifiers with new caps on all channels if that is indeed the problem.
Warm amplifiers up a bit if that can be done through selection of specific parts.

Please help! Are bad caps my problem?

poynton · 5th January 2010, 01:26 AM

If possible, some photos of the modules and how they are inserted may help.

My first thought would be bad contact rather than caps.

Andy

.

HifiGuy84 · 5th January 2010, 04:03 AM

HifiGuy84 · 5th January 2010, 04:05 AM

There are a few pics of the amp. I have more posted on my flicker account.

Amp - a set on Flickr

HifiGuy84 · 5th January 2010, 04:06 AM

I assume by contact you mean that something has come loose somewhere in the chain. Wondering if that could be the case for 3 channels in two different amps.

Cal Weldon · 5th January 2010, 04:07 AM

Guys I have moved this to solid state. Troubleshooting is for problems with the forums.

Stuey · 04:16 AM

I have no experience with these amps, but are the modular cards mounted in sockets like a PC? If so, maybe they require removal and reseating.

My first thought, however, is that a selector or switch requires cleaning. I can't see from the photos that they have any such selectors, though.

HifiGuy84 · 5th January 2010, 04:35 AM

No, there are hard clips with wiring a wiring harness. I have no doubt that contact is being made on these. I have traced all the wiring and everything seems like its in good shape. No switches or selectors on these. They utilize a pre-amp. Is there a part which can go bad which would cause intermittent output and fuzzy or scratching sound on occasion, often times while in the first 30min of listening.

poynton · 07:16 AM

AS the design is modular, does the fault move when you change the modules over?

Certainly, it sounds like it could be caps if it lsats only 30mins or so after switching on.

.

3rd January 2010, 02:28 AM	#1
HifiGuy84 diyAudio Member Join Date: Jan 2010	Sherbourn, Bad Caps? Newbie needs help Hello everyone, I work in the sales and system design end of the A/V industry, but am extremely new to most of the actual repair and workings of two amplifiers I own. I have a 5ch. and a 2ch. Sherbourn amplifier 5/1500A. The chassis are the same and are of a modular card design. Each channel has its own card and transformer. In at least two channels on the five channel and one channel on the two channel I am have the same issues. There is crackling and sometimes the channel won't work at all. From what I am reading, this could potentially be a problem with the caps going bad. Is this the case? The amplifiers are 12-13 years old. I have never done any major repair like this in the past, but am interested in the undertaking. If it is indeed the caps going bad, what should I replace them with? I would like to replace them all at once so the amp continues to work down the road and the channels are matched. I am not sure if the caps may have any bearing on the overall tonality of the amps, but if I could I would warm them up a bit. For my taste, they are too analytical with my Monitor Audio GS60's. What tools and parts would I need and can I do this as a newbie? Any other parts I should replace at the same time? Any other advice would be appreciated. Best regards Britton

5th January 2010, 12:34 AM	#2
HifiGuy84 diyAudio Member Join Date: Jan 2010	Maybe a list would be easier since no one has responded. Problems: Channels on two different amps I own are starting to go. Sometimes they just do not work other times they scratch and hiss. These are stand alone amps on different systems both same make model and age. I am new at this, but familiar with things on a conceptual level. Thoughts: From things I have read these problem could be as a result of the caps going bad. Goals: Fix amplifiers with new caps on all channels if that is indeed the problem. Warm amplifiers up a bit if that can be done through selection of specific parts. Please help! Are bad caps my problem?

5th January 2010, 01:26 AM	#3
poynton Magneto the Gravity Man diyAudio Member Join Date: Mar 2005 Location: A life on the ocean waves when I'm not at home in N. Wales (but I'm not Welsh so no sheep jokes!)	If possible, some photos of the modules and how they are inserted may help. My first thought would be bad contact rather than caps. Andy . __________________ If it ain't broke, break it !! Then fix it again. It's called DIY !

5th January 2010, 04:05 AM	#5
HifiGuy84 diyAudio Member Join Date: Jan 2010	There are a few pics of the amp. I have more posted on my flicker account. Amp - a set on Flickr

5th January 2010, 04:07 AM	#7
Cal Weldon Speakerholic diyAudio Moderator Join Date: Jan 2004 Location: British Columbia	Guys I have moved this to solid state. Troubleshooting is for problems with the forums. __________________ Next stop: Margaritaville Some of Cal's stuff \| Cal Weldon Consulting


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

5th January 2010, 04:03 AM	#4
HifiGuy84 diyAudio Member Join Date: Jan 2010

5th January 2010, 04:06 AM	#6
HifiGuy84 diyAudio Member Join Date: Jan 2010	I assume by contact you mean that something has come loose somewhere in the chain. Wondering if that could be the case for 3 channels in two different amps.

5th January 2010, 04:11 AM	#8
Stuey diyAudio Member Join Date: Mar 2006 Location: Perth, Western Australia	I have no experience with these amps, but are the modular cards mounted in sockets like a PC? If so, maybe they require removal and reseating. My first thought, however, is that a selector or switch requires cleaning. I can't see from the photos that they have any such selectors, though. Last edited by Stuey; 5th January 2010 at 04:16 AM.

5th January 2010, 04:35 AM	#9
HifiGuy84 diyAudio Member Join Date: Jan 2010	No, there are hard clips with wiring a wiring harness. I have no doubt that contact is being made on these. I have traced all the wiring and everything seems like its in good shape. No switches or selectors on these. They utilize a pre-amp. Is there a part which can go bad which would cause intermittent output and fuzzy or scratching sound on occasion, often times while in the first 30min of listening.

5th January 2010, 07:11 AM	#10
poynton Magneto the Gravity Man diyAudio Member Join Date: Mar 2005 Location: A life on the ocean waves when I'm not at home in N. Wales (but I'm not Welsh so no sheep jokes!)	AS the design is modular, does the fault move when you change the modules over? Certainly, it sounds like it could be caps if it lsats only 30mins or so after switching on. . __________________ If it ain't broke, break it !! Then fix it again. It's called DIY ! Last edited by poynton; 5th January 2010 at 07:16 AM.

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