I have Pair of Nemo and last year one of then (left Channel) seems to breaking up the sound. I called Electrocompaniet and they told me to send it to service center to replace the output Relay. so I did and after that Amp sounded way more open to the right channel. but right channel was still not sounding bad but one can figure out the sound from left (with New relay) was far better than the right one. Fast Forward 6 months right channel has developed the same fault, sound is now breaking up just as it was in left channel before replacing the relay. my frustration is I asked service center if its recommended to replace the replay on both channels and I was told why repair if its not broken. regardless to what they said, I now need to go through the same exercise I again.😡
But wait a minute, I realize that output replays can be cleaned up. I am trying to DIY the cleanup part before I send it to repair. If cleanup can solve my problem I would be a happier DYIer 😀. but I need community's support to guide me how to identify the relay and how to reach there. I know Nemo is just 2 AW250 stuck together 🙂 so if anyone has done it on AW250, that would just make it perfect.
Appreciate your response in advance.
But wait a minute, I realize that output replays can be cleaned up. I am trying to DIY the cleanup part before I send it to repair. If cleanup can solve my problem I would be a happier DYIer 😀. but I need community's support to guide me how to identify the relay and how to reach there. I know Nemo is just 2 AW250 stuck together 🙂 so if anyone has done it on AW250, that would just make it perfect.
Appreciate your response in advance.
That's very disappointing advice from people who should know better! I often clean amplifier relays as part of servicing. The relays usually have a transparent cover although some are orange and some black, or blue.
Getting the cover off can be quite difficult, especially without removing the relay from the PCB.
Most often relays are 'double throw' meaning there is a common contact that moves, and two fixed contacts that it swaps between when energised or not; on the energised contact side is used and that is what needs cleaning.
The clean the contacts I use a combination of DeOxit D5 spray and a piece of stiff paper that is cut into a strip that fits between the relay contacts. The paper, moistened with D5 is used to burnish the contact surfaces with the contacts held closed by pressing on the armature that moves the contacts. Keep buffing with fresh strips of paper until it comes out clean.
Alternatively get the part number off the faulty relay and replace it with a new one. It is highly unlikely to be a special custom Electrocompaniet part.
If you need help identifying the relay, post an internal picture.
Getting the cover off can be quite difficult, especially without removing the relay from the PCB.
Most often relays are 'double throw' meaning there is a common contact that moves, and two fixed contacts that it swaps between when energised or not; on the energised contact side is used and that is what needs cleaning.
The clean the contacts I use a combination of DeOxit D5 spray and a piece of stiff paper that is cut into a strip that fits between the relay contacts. The paper, moistened with D5 is used to burnish the contact surfaces with the contacts held closed by pressing on the armature that moves the contacts. Keep buffing with fresh strips of paper until it comes out clean.
Alternatively get the part number off the faulty relay and replace it with a new one. It is highly unlikely to be a special custom Electrocompaniet part.
If you need help identifying the relay, post an internal picture.
Hi etalks,
The service person is an idiot. You always replace both relays! I've been in the service industry for more than 45 years and wouldn't dream of doing what they did.
For cleaning, use a non-residue cleaner. Do not use anything that leaves a film on the contacts.
When turning the system on or off, the volume must be zero or you will damage the contacts.
-Chris
The service person is an idiot. You always replace both relays! I've been in the service industry for more than 45 years and wouldn't dream of doing what they did.
For cleaning, use a non-residue cleaner. Do not use anything that leaves a film on the contacts.
When turning the system on or off, the volume must be zero or you will damage the contacts.
-Chris
I used CRC 2-26, it is supposed to leave a film that is broken during contact, and forms as the contact is broken.
This reduces oxidation due to arcing, and greatly increases contact life.
I used it on multiple contactors, switching 2 to 25 kW on heaters and motors.
It works.
The recommended procedure was to clean off the black residue with Carbon Tetrachloride or PCE, though you can try iso alcohol.
Then spray monthly, annual cleaning recommended, bear in mind that alcohol disintegrates polycarbonate, which is common in relay covers.
For a small old relay, just replace it with a higher rated one in the same size, and use a reputed brand.
I used to do that in temperature controllers, Chinese relays were just 10 Rupees, less than 15 cents of US money, and O/E/N about 1.5 USD or less. After 15 years, justified to replace rather than repair.
In the temperature controller output, which was to switch contactors, I used MOVs, they helped increase the life a lot.
The covers are a snap fit, mostly needing removal from PCB, and pitted contacts don't work as well as new ones.
For a 1 - 3 dollar part, not worth the risk of damaged PCB.
You could put a MOV across the mains supply in the amplifier to suppress surges and noise, line to neutral.
This reduces oxidation due to arcing, and greatly increases contact life.
I used it on multiple contactors, switching 2 to 25 kW on heaters and motors.
It works.
The recommended procedure was to clean off the black residue with Carbon Tetrachloride or PCE, though you can try iso alcohol.
Then spray monthly, annual cleaning recommended, bear in mind that alcohol disintegrates polycarbonate, which is common in relay covers.
For a small old relay, just replace it with a higher rated one in the same size, and use a reputed brand.
I used to do that in temperature controllers, Chinese relays were just 10 Rupees, less than 15 cents of US money, and O/E/N about 1.5 USD or less. After 15 years, justified to replace rather than repair.
In the temperature controller output, which was to switch contactors, I used MOVs, they helped increase the life a lot.
The covers are a snap fit, mostly needing removal from PCB, and pitted contacts don't work as well as new ones.
For a 1 - 3 dollar part, not worth the risk of damaged PCB.
You could put a MOV across the mains supply in the amplifier to suppress surges and noise, line to neutral.
Last edited:
Hi NareshBrd,
-Chris
The film burns. This only works making or breaking with no energy. You need to use a no residue cleaner. This is true for power switches and speaker switches too.
-Chris
Maybe you have a different formulation.
I have seen this locally sourced spray visibly reduce arcs in the contactors. Life increase 3 times.
Recommended to me by the service engineers of the people who made contactors, Larsen & Toubro, now the business is with Schneider.
WD40 uses LPG (propane - butane combination) as the propellant in Germany, and a refrigerant type modified pentane in North America. Same company, and same product name.
So your results can be different from mine, even though we seem to be using the same product.
De Oxit spray is also recommended here on this forum, I do not see it here in India. So my advice is based on my personal experience.
I have seen this locally sourced spray visibly reduce arcs in the contactors. Life increase 3 times.
Recommended to me by the service engineers of the people who made contactors, Larsen & Toubro, now the business is with Schneider.
WD40 uses LPG (propane - butane combination) as the propellant in Germany, and a refrigerant type modified pentane in North America. Same company, and same product name.
So your results can be different from mine, even though we seem to be using the same product.
De Oxit spray is also recommended here on this forum, I do not see it here in India. So my advice is based on my personal experience.
I used to use 2-26 before I got onto DeOxit in the '80s. There's no comparison IMHO. 2-26 seems to need to be reapplied every few months (at least the CRC formulation in Australia), whereas DeOxit seems to be a permanent solution. I have never needed to reapply DeOxit to anything.
One reseller in listed in India here: Rig My Gig | it's yOUR show !
Or buy online here: Shop - CAIG
One reseller in listed in India here: Rig My Gig | it's yOUR show !
Or buy online here: Shop - CAIG
Relay contacts are generally made (tablet pressed and sintered) from powdered, soft metal composites and arcing damages them, causing pitting as well as a build-up of metal oxides, sulphates etc. unless the whole unit has been sealed and filled with inert gas, as are signal relays, reed relays and so on.
If the relay is not a sealed type, you can access the contacts to clean them, but do also burnish them with a relatively soft material like cloth or Kraft paper adhered to a metal or wooden splint. Don't file, sand or roughen the surfaces making matters worse by leaving scored, uneven or misaligned contact surfaces, should the contact mounting arms be bent in the process.
I've also read here that using specialised, very fine polishing materials like crocus paper are ideal finishing treatments but these are probably difficult to find if not unobtanium nowadays. I've actually used a paste of diamond powder which is used industrially as a lapping medium for mechanical seal surfaces and other high precision apps but my tiny stash of a gram or so has long gone.
If the relay is not a sealed type, you can access the contacts to clean them, but do also burnish them with a relatively soft material like cloth or Kraft paper adhered to a metal or wooden splint. Don't file, sand or roughen the surfaces making matters worse by leaving scored, uneven or misaligned contact surfaces, should the contact mounting arms be bent in the process.
I've also read here that using specialised, very fine polishing materials like crocus paper are ideal finishing treatments but these are probably difficult to find if not unobtanium nowadays. I've actually used a paste of diamond powder which is used industrially as a lapping medium for mechanical seal surfaces and other high precision apps but my tiny stash of a gram or so has long gone.
Hi Ian,
Yes, the plating on the contacts is thin. You go through that and you're into the base metal. The contacts are then done. If they are pitted, they are done.
I'll just say this again. From power relay manufacturers and any good service person. Contacts must be left clean and dry. Period. If you do work that you charge for, follow that advice. Contacts are self-wiping. Any coating will burn if the contacts open or close under load. Period.
What you do to your own stuff ... I don't care. But treat other people's equipment properly and use a non-residue cleaner. Doesn't matter the brand, and de-ox-id is definitely NOT suited for speaker relay contacts or any kind of power switch. If there is an arc, even a small one, the coating absolutely will burn and leave deposits. Period.
-Chris
Yes, the plating on the contacts is thin. You go through that and you're into the base metal. The contacts are then done. If they are pitted, they are done.
I'll just say this again. From power relay manufacturers and any good service person. Contacts must be left clean and dry. Period. If you do work that you charge for, follow that advice. Contacts are self-wiping. Any coating will burn if the contacts open or close under load. Period.
What you do to your own stuff ... I don't care. But treat other people's equipment properly and use a non-residue cleaner. Doesn't matter the brand, and de-ox-id is definitely NOT suited for speaker relay contacts or any kind of power switch. If there is an arc, even a small one, the coating absolutely will burn and leave deposits. Period.
-Chris
Many moons ago I was a tech in a British electro mechanical exchange. There are thousands of relay's used. We never put anything on the contacts for any kind prevention.
Presumably you mean Caig DeoxIT is not suitable for speaker relay contacts. Why do you make that statement? (It is contrary to my experience of the past 35 years, so I am wondering what I have missed.)
Here the relay contacts are hard copper beryllium tungsten alloy, silver plated for better conductivity and long life. Rivets really, fixed to strips, in power contactors.
The instruction for cleaning also said put them back as they were...the contacts are strips in spring loaded holders, and in / out contacts below...so the strips were to be removed, cleaned, the fixed contacts cleaned, put back in place, then the next to be done.
They tend to get the same highs and lows on facing contacts, so it was the way...to put them back as they were.
Frequency of switching in heaters was about 15 seconds, and on motors once in 4 to 8 hours.
Heater loads are 2 to 3 kW on my machine, motor is 25 HP /18.75 kW with a star delta starter, 2 main and a small auxiliary contactor.
The instruction for cleaning also said put them back as they were...the contacts are strips in spring loaded holders, and in / out contacts below...so the strips were to be removed, cleaned, the fixed contacts cleaned, put back in place, then the next to be done.
They tend to get the same highs and lows on facing contacts, so it was the way...to put them back as they were.
Frequency of switching in heaters was about 15 seconds, and on motors once in 4 to 8 hours.
Heater loads are 2 to 3 kW on my machine, motor is 25 HP /18.75 kW with a star delta starter, 2 main and a small auxiliary contactor.
Last edited:
But wait a minute, I realize that output replays can be cleaned up. I am trying to DIY the cleanup part before I send it to repair. If cleanup can solve my problem I would be a happier DYIer 😀. but I need community's support to guide me how to identify the relay and how to reach there. I know Nemo is just 2 AW250 stuck together 🙂 so if anyone has done it on AW250, that would just make it perfect.
Appreciate your response in advance.
Hi, some questions:
A. what are the original types?
B. What is the replacement type?
It is plain silly to replace only one of them. I never clean or sand contacts as the problems always seem to return then. I use sealed relays with higher rated bifurcated contacts in general.
I did say that it is worth the trouble for large contactors, for small relays it is not worth the trouble.
My heater contactors are 16 and 25 Amps per pole, three pole units.
Speaker relays are much smaller, and the working frequency is much less.
The service people should have changed both relays, careless of them, they should be more experienced as to what are the common faults in the equipment they work on, and how to keep the customer happy.
My heater contactors are 16 and 25 Amps per pole, three pole units.
Speaker relays are much smaller, and the working frequency is much less.
The service people should have changed both relays, careless of them, they should be more experienced as to what are the common faults in the equipment they work on, and how to keep the customer happy.
Hi NareshBrd,
Contactors (heavy relays) are always left, dry especially like yours.
Hi johnmath,
Your experience is in direct opposition to mine. As a young tech, it seemed to make sense to do what you are doing but the failure rate was high if there was any arcing or switching under load. An older tech gently explained what an idiot I was and that my training was not complete. I was then given a course, with examples, on how to clean relays, switches, signal relays and switches and also controls. My training was very thorough and proved to be correct over 3 + decades of practice in my field. That's all I can say.
-Chris
Contactors (heavy relays) are always left, dry especially like yours.
Hi johnmath,
Your experience is in direct opposition to mine. As a young tech, it seemed to make sense to do what you are doing but the failure rate was high if there was any arcing or switching under load. An older tech gently explained what an idiot I was and that my training was not complete. I was then given a course, with examples, on how to clean relays, switches, signal relays and switches and also controls. My training was very thorough and proved to be correct over 3 + decades of practice in my field. That's all I can say.
-Chris
All I can say is that the spray increased the contact life greatly.
Larsen & Toubro sold contact kits, you could change the fixed and moving contacts after they wore out.
Contactors developed chattering due to armature wear, that was after several contact sets, then they were to be replaced.
I used spray, and MOVs, and the arcing, which was the cause of wear, reduced.
I used to clean them regularly - every six months, and spray once a month.
Then I switched to solid state relays, and moved out of that particular task.
You were practically trained, and I was told what to do by a service engineer of the manufacturer.
My experience is very limited compared to yours.
Leave it at that.
As for the original poster, you can try servicing it only in break down conditions, the relay will be aged, springs weak, pivots worn, apart from pitted contacts.
What I mean is that when the amp must work, and must be made to work, failure is not allowed...then take the trouble of servicing the relay.
Better to replace with a higher rated unit from a reputed brand that is easily available.
Larsen & Toubro sold contact kits, you could change the fixed and moving contacts after they wore out.
Contactors developed chattering due to armature wear, that was after several contact sets, then they were to be replaced.
I used spray, and MOVs, and the arcing, which was the cause of wear, reduced.
I used to clean them regularly - every six months, and spray once a month.
Then I switched to solid state relays, and moved out of that particular task.
You were practically trained, and I was told what to do by a service engineer of the manufacturer.
My experience is very limited compared to yours.
Leave it at that.
As for the original poster, you can try servicing it only in break down conditions, the relay will be aged, springs weak, pivots worn, apart from pitted contacts.
What I mean is that when the amp must work, and must be made to work, failure is not allowed...then take the trouble of servicing the relay.
Better to replace with a higher rated unit from a reputed brand that is easily available.
Last edited:
Oh, one more thing, if only one of the two contacts is used, try using both...
Some leaf type relays have two sets of contacts, and sometimes only one is used.
Using both will halve the load on each contact. You will get more life as wear due to arcing will reduce.
Some leaf type relays have two sets of contacts, and sometimes only one is used.
Using both will halve the load on each contact. You will get more life as wear due to arcing will reduce.
Amazon US is a little confused in its 4000+ hits, but there are dozens of abrasive sheets to 5000 and even 10000 grit.
It seems there was a US Standard cancelled in 1989. (Probably the makers of improved products did not want to be bound by old specs.)
Fountain pen geeks use fancier stuff but you probably can't get THAT fussy inside an audio relay.
Perhaps because the only time an amplifier's speaker relay should ever switch under load is in the instance of a catastrophic failure of the amplifier.