Finding mains transformers.

[Joe bags]

Hi there

I have a Carlsbro Gamma 12/300 active monitor speaker.
The mains transformer is faulty and I need to replace it.

I've tried Carlsbro and it's discontinued so they said they don't have any spares.
The make of the transformer is Soundking (China)
Model no. SKO-150-42 FP212A
I tried them aswell and had no luck.

Outputs are

42v - 0 - 42v
25v - 0 - 25v
19v - 0 - 19v.

Does anyone know where I might be able to find a suitable replacement?
I find it hard to find mains transformers online if they are not available directly form the manufacturer.

I found a guy in the UK who makes transformers but the price didn't work out economical for the repair with the amount of labour involved in making just the one.


Here's a few photos.

Any thoughts appreciated as this is an ongoing problem I seem to have.

Regards

Joe

[Jazz P Bass]

.

Outputs are

42v - 0 - 42v
25v - 0 - 25v
19v - 0 - 19v.

Those are some odd voltages.

[g1]

Those are some odd voltages.

Maybe another case of showing what the DC rectified voltages will be?
A schematic would be helpful.

[Joe bags]

I had no luck getting schematics.

[J M Fahey]

This might be solvable, but first you must consider a couple points:

1) are you certain the transformer is dead?

If open primary it might be a thermal fuse.
Those sometimes can be digged out and replaced/jumpered.

2) what/if you spend $$$ for a new transformer and then the amp itself is unrepairable?
Who will pay for that transformer?

As of soundking, that's what your powered monitor is, Cralsbro is just the rebrander/distributor.

Maybe you can find them and they can supply schematics and parts.

Don't hold my breath on that though

[The Dude]

https://www.studiospares.com/Headpho...mer_248340.htm

[J M Fahey]

Hey Dude !!! You FOUND it!!!
Great

skills

FWIW that's a generic, mass produced powered speaker, sold under 100 different brands ... just like webbbilly's "Guitar Research T64RS Valvestate" .

This particular powered speaker seems to be the same as Studiospares Fortissimo 12A (cool name ) and Metro Audio Systems SP12A .... and certainly others.
Oh well.

You were lucky that at least one of them offers spares; standard M.O. is to buy a lot, say 50 to 500 , cash them and forget everything about it.

I have had my share of similar generic products, some even sold under brands like Mackie or "Yahama"(sic), go figure ... all Soundking inside.

The local importer of one of those told me that they met the OEM guys in a Trade Fair, and the minimum order was just 50 pairs, with any brand screened on them.

They never even asked for the schematics , and when they had to service a couple within a year they had to get a guy who could work without schematics or original parts ... which by the way is standard here in Argentina so not that a big deal.

In fact I have a couple left by a customer who didn't want to wait and just bought another pair, both have burnt power amps and one of them is missing the 15" speaker , sent for reconing to a guy who later can't be found .

FWIW I'll complete that one with one of my 15"speakers, replace burnt amps with a couple of my own MosFet boards (cheaper and faster than repairing the original ones) , use the original PTs, and cash them in our version of EBay.

Better than gathering dust and cobwebs in a back room

[The Dude]

It wasn't any giant feat, really. I just Googled the number on the transformer from the pics posted + the word transformer and it was the first site in the search. Even better, it's in London and our OP is in Dublin, which should be in "cheap shipping range".

Sure, I could let you think I'm some evil genius, but the truth is much more simple... I passed typing class with a B+.

[J M Fahey]

Don't be so modest, you found it and others did not, that's the point

And they'd better hurry because available stock is 2 / two / II / a pair you name it.

With no way to get another if they run out.

I *guess* Soundking sent them a couple transformers, a couple stuffed PCBs, maybe a couple pots and knobs, as part of a package of , say, 100 to 500 amps, to be able to offer some warranty servicing if needed, without bothering the Asian Factory .... and now they are turning the leftovers into cash.

A Forum member, JJRFrondelli, who runs a big service shop in NY is Behringer main service station in the area, and he got overstocked with Behringer parts which the Factory thought would be needed (no doubt based on some failure analysis software) , so much so that for models way out of warranty and not seen any more he had to organize a "fire sale" , offering , say, assorted random value 10 pots bags for a couple dollars, same for switches, knobs, etc.

I didn't buy any just because I'm too far away, otherwise I would have visited him with a pickup truck and emptied that room.

Just imagine Enzo's back room, after 50 years in the industry

[Joe bags]

Dude, you the man!

[Joe bags]

I was pretty certain the transformer was dead a few months back
but will defo re check this as it will cost a few quid on parts just to test the rest of the amp.
And more than likely it will be me who bears the cost if it doesn't work out.

Might try to get some funds up front for the parts and explain the situation to the customer.

[Joe bags]

So just to update on this. I got a new mains transformer installed it but there was still a problem.
With power being applied I could hear some sort of crackling noise. It was the transformer heating up.

So there was obviously something else wrong with the amp.
I swapped out the LM3866 power amp chip.

All seems to be good now. Gonna give a good test now.

This one was lurking at the back of the workshop for a while now.
good to get it done.

[km6xz]

SoundKing is making a run at Behringer's lower end while Behringer's parent, Music Group is buying up higher end brands like TC Electonic, TurboSound, Midas and anything else not owned by Harmon.
Behringer never had a parts list the matched the parts used in the gear. When they opened their own distribution in the US and separated from Samson, they only had salesmen and no technical staff or managers so they approached me on the west coast and dbm, where John works, on the east coast to be the replacement of the factory service they did not have the expertise to create or desire to deal with. I agreed to terms that seemed pretty good for us, not high rates but enough volume to become very efficient so modest rates could be very profitable. A couple weeks later, I show up at the shop and a big interstate furniture tractor/trailer rig was blocking my warehouse roll up.
doors. The driver was asleep and waking him asking him to move his rig because we had truck deliveries coming and needed to get the forklift out for the pallets. He replied that he was making a delivery to us. Furniture trailers are LOONG, bigger than legal for normal cargo since finished furniture has low mass for the size of items. He opened the rear doors and it was full of Behringer, including dozens of larger MX9000 24 bus consoles without boxes....524 warranty items to repair, many with no shipping boxes, no indication of problems and no parts. Eventually we got pallets of parts but they were not exact replacements for anything, some mechanical parts were never identified. That is how John ended with a lot of parts. They had a small shop, not surprising being in NYC where monthly rent costs about the total selling price for a 3 bedroom house in Kansas. We had a very large shop with many techs. For a couple years we were the only tech support Behringer in the US and were repairing thousands each year during that era when they really took off and expanded in sales.
I did not mind working on them without much tech information and some were pretty decent units like the rack mount compressors and small mixers. That low end of pa systems, passive and active speakers, power amps, bass amps, mixers and powered mixers is the market Soundking is going after, by harnessing many small sales companies as their distribution channel. They are particularly effective in developing markets of Asia, South America, here in Russia and middle east. Expect to see a lot more of their rebranded gear. With just a few circuit board between them, figure one out and you have figured out 50 other brands where the same board was used.