Power Amp - Replacement Power Switch

[Dennis Peacock]

Does anybody here know where I can get a replacement power switch for a Ross Systems Mega Amp 800?

[Malcolm McLeod]

Not positive, but seems like someone bought Ross ..... thinking Akai??

If Akai can't cross reference the part, then my electrical gadget go-to-supplier-of-last resort-cuz-they have-everything is Allied Electronics.

[Ken Fitzgerald]

Do you have a schematic on it Dennis?

[Dennis Peacock]

Ken,
I do not have anything on this old amp. The switch is going out on the church's sound system and I narrowed it down to the power switch on this amp. I think the church paid something like $200 the last time to have the switch replaced. I think I can do it for cheaper.......if I can find the replacement part. :)

[Jim Koepke]

Ken,
I do not have anything on this old amp. The switch is going out on the church's sound system and I narrowed it down to the power switch on this amp. I think the church paid something like $200 the last time to have the switch replaced. I think I can do it for cheaper.......if I can find the replacement part. :)

Can you post a picture?

One of my home appliance switches needed some work last weekend and it was easy peasy.

Trying to guess what kind of switch set up your equipment has without knowing if it is part of a volume control, a separate rocker, slide, turn or toggle switch will give me four chances out of five to guess wrong.

Often components will have a manufacturer listed along with a part number on the component. Some items are interchangeable and can be bought locally from a local appliance/electronics repair/parts shop.

jtk

[David L Morse]

Does it look like this?
373509
That's most likely a very standard switch. Here's (https://www.amazon.com/Power-Rocker-Switch-DPDT-30-10082/dp/B000LDV59Q/ref=sr_1_2?ie=UTF8&qid=1513032172&sr=8-2&keywords=power+rocker+switch) one example.
You need to check the hole size. This is what that Amazon part requires:
373513

In addition to Amazon you can check Digi-Key or Mouser or as Malcolm suggested Allied If that's not the right size. You want at least a 16A rating at 125 Volts.

The existing switch should be marked with both ratings and a manufacturer's part number.

[Ken Fitzgerald]

Dennis,

I have a friend who owns a music store and is the local areas repair guy for amps, mixers etc. I will go by his store tomorrow and see if he has schematics, parts breakdowns and recommendations. I will post back here, my friend.

As Jim, said, often the current and voltage ratings are printed right on the switch.

[Dennis Peacock]

Here is a pic of the switch that is currently in the amp.

373584

[Myk Rian]

Is there room behind the panel for a toggle switch?

[Dennis Peacock]

Probably. I haven't taken it out of the rack yet....but I can.

[Adam Herman]

that switch is a standard radioshack sort of part. most good hardwares will have a toggle switch that will fit in the hole behind it.

[Steve Schlumpf]

Dennis, I used to repair all sorts of audio gear and power switches are fairly simple. Check the info on the switch, then check out this site to see if you can locate a replacement. https://www.mouser.com/ (https://www.mouser.com/)

[Dennis Peacock]

Dennis, I used to repair all sorts of audio gear and power switches are fairly simple. Check the info on the switch, then check out this site to see if you can locate a replacement. https://www.mouser.com/ (https://www.mouser.com/)

Thank you Steve. Much appreciated. Will do.

[Ken Fitzgerald]

Dennis,

I just got back from my friends business. He advised as Steve did, going to Mouser, Allied or Newark. I will spend some time looking. Getting information off the switch would be a help.

[John K Jordan]

The only things that matter in a switch are its voltage and current ratings and the configuration - things like single/double pole, momentary, and special environmental conditions.

A 110v power switch is probably the simplest sort, a single-pole toggle switch for dry locations. If you can't find a replacement part just get any switch with suitable current rating and make some means to mount it securely, perhaps even drilling another hole and covering the old hole. If you can't find the current rating printed on the switch either get one way over-rated or see if there is an electrical plate or sticker on the back of the amplifier giving the device amperage.

The switch on my older drill press went out and I could not locate a replacement. It was rectangular and snapped into a rectangular hole in a mounting plate. I bought a switch that would handle the current, cut a new plate from something, and cut a rectangular hole for the switch. Has worked fine for the last 15 years.

Also, I've repaired many switches over the year by disassembling and cleaning/polishing the contacts, adding a dab of dielectric grease, then reassembling. Sometimes a switch goes bad because of broken components or burned contacts and can't be repaired but I've seen more that could be restored than couldn't. The switch body often snaps together and can be pried apart, has small screws, or sometimes rivets which can be drilled out.

JKJ

[Jim Koepke]

The switch body often snaps together and can be pried apart, has small screws, or sometimes rivets which can be drilled out.

This is more true of older switches than the newer ones. Things used to be made to be repairable. Now everything seems to be made to sell you the next one.

My recent switch repair was a slide switch that stopped making contact. Those can usually be taken apart and tweaked. Turned out this one was a double throw switch so all it needed was a lead removed from one terminal and soldered to the unused terminal. If it dies in the future there might be one of the right size in my parts piles or at least the right size is known.

jtk

[John K Jordan]

This is more true of older switches than the newer ones. Things used to be made to be repairable. Now everything seems to be made to sell you the next one.


I suspect it is more to save a dime on the production cost than planned obsolescence, but maybe it's some of both. I do admit to not being easily deterred. Sometimes things are heat welded/glued together making them harder to get apart. A very thin saw is sometimes useful here.

The little very thin circular saw blade made for Dremel is probably the best. Hand saws next, then Fein multitool, but the blade on the multitool is a thicker.

I think most rocker switches, however, are still snap-together since that is cheap to make - the body is a one piece "box" with the contacts molded in place for rigidity and alignment. The rocker is pressed into the rectangular opening at the top by spreading the plastic a bit so the nubs molded on the rocker snap into place to form the rocker axle. (These sometimes have little ramps or slopes molded on the pieces so they snap together a lot easier than they come apart.) To remove, insert a thin, sharp spatula or knife in the crack near the center of the rocker, pry the case outward and pop the rocker out. Watch out, loose pieces may fly. (I once lost a tiny ball bearing detent in a switch by foolishly disassembling the switch over a pile of sawdust at the lathe! Eventually found it with a magnet.) In my experience it is more common than not to find a switch that can be repaired.

JKJ

[Jim Koepke]

Sometimes things are heat welded/glued together making them harder to get apart.

On my last encounter with a small case put together in this manner, the case was placed in my large vise and slowly compressed. When a slight pop was heard it was inspected to see where it had opened and another vise compression was used to pop the other side.

A zip tie was used to hold the case back together.

jtk

[michael langman]

I bought a very similar rocker switch from mouser electronics about 10 years ago. It cost lass then a dollar.
For the next 5 years after that I received a mouser catalog in the mail that weighed about 12 pounds, and had millions of electronic parts in it.

[Dennis Peacock]

Well, today I pulled the amp out of the sound booth and brought it home with me. I just got the broken switch out of the chasis. The swith is rated for DC 12V - 30 Amp and is a R13-133. The swith has 3 conductors on it but only 2 of them were hooked up to the amp wiring. The switch says:
Earth
Load
Supply
The earth connection was not used. So in my simply mind, this switch could have just as easily been a common single pole switch for your home. :)
I'm thinking that if I can find a toggle switch locally that is AC 120V - 20 Amp, I should be good to go. Thoughts???

[John K Jordan]

Well, today I pulled the amp out of the sound booth and brought it home with me. I just got the broken switch out of the chasis. The swith is rated for DC 12V - 30 Amp and is a R13-133. The swith has 3 conductors on it but only 2 of them were hooked up to the amp wiring. The switch says:
Earth
Load
Supply
The earth connection was not used. So in my simply mind, this switch could have just as easily been a common single pole switch for your home. :)
I'm thinking that if I can find a toggle switch locally that is AC 120V - 20 Amp, I should be good to go. Thoughts???

Dennis,

Yes, a single-pole single-throw switch. But what current rating is needed?

You might check to see if the amplifier itself has electrical specs on a plate or sticker on the back to see what switch rating is actually needed. It it typical to use switches rated higher than the load for no reason other than availability. If the sticker is missing, I personally would jumper the power switch, put a current meter in line (or use a clamp-on) and measure the actual current use with the amplifier running at the usual power. (This method may not be best if lacking experience with electrical equipment.) You might be able to use a switch with lower ratings than listed on the switch.

Another hint may be the size of the wires connected to the switch and the size of the wires in the power cord. A 20 amp load is a LOT of power and requires large wires, typically 12ga. (This isn't a massive amplifier such as used in outdoor arenas, is it?)

The picture of your switch looks like it has a pilot light that is supposed to come on when the switch is turned on as does the terminal labeling. (I don't know why they would use this type of switch in an application with an obvious power indicator light mounted next to it - maybe someone replaced it once before and used whatever switch they could find.) I'd have to check but I believe the earth terminal is connected to ground when you want the light to turn on when you turn on the switch. If not using the indicator light in the switch, any toggle switch of sufficient rating or higher will work. In fact, I had a rocker switch that looked much like yours that mounted in a round hole drilled in the chassis - a standard toggle switch may fit in the same hole. Do you have a Radio Shack or an electrical supply house nearby?

I sure wished I lived around the corner from you! I'd probably find a switch in my parts bins or pull one from an old piece of equipment and just come over there and fix it!

JKJ