HELP! - Need a Repair Recommendation for my Raysonic Amp


After 5 years of flawless service, my Raysonic SP-66 tube integrated wouldn’t power up yesterday evening. The fuse at the electrical input was blown, but it still didn’t power up even after I replaced the fuse with one that tests good. I took the bottom plate off, looked around inside, and didn’t see anything obviously wrong. The 2 internal fuses tested good.

It ocurred to me that the power button was probably in the ON position when I went to start listening. This suggests that either I accidentally left it on the last time I listened, or one of my grand-children turned it on, and it over-heated. I also noticed a paint blister on one of the transformer covers suggesting that it over-heated.

My suspicion is the power transformer, but I don’t how to confirm it, or replace it if it is in fact the problem.

Raysonic is long gone and they had a reputation for being secretive with product details, so I doubt that anyone will have schematics or parts values.

The amp has been a pleasure and it is a perfect match for my CD128 CD player which has also performed flawlessly.

Therefore, I would very much like to get the amp repaired, as long as it isn’t cost-prohibitive, but I don’t know who to turn to, much less trust, to do the work.

I would hope that a well-qualified tube amp technician would be able to fix this even if they are not specifically familiar with Raysonic. I just don’t know who that is.

So, I would appreciate suggestions/recommendations of someone who may be able to help me out.

Thanks in advance.

Brady




bbroussard
Shouldn't overheat merely being left on. If it did, the transformers would be the last to get hot. Transformers don't generate hardly any heat in normal operation. They tend to last pretty much forever. But they are made of coiled wire, which if poorly insulated could short and that would create a whole lot of heat. You could test for that pretty easy with a volt/ohm meter and some basic transformer knowledge. Or like you say any reasonably good tech should be able to diagnose and fix. I would call your local audio stores and ask for a recommendation. 
The old US Distributor might be able to fix it (sorry forgot who, but I think he's in PA; I searched 4 pages but did not see him). He was no help for my Raysonic 228, which sits in a box to this day, some 6 years later
Unless you are 100% sold on tubes Underwood HiFi has a fab sale on a couple W4S integratedes
It seems unlikely that the power transformer has failed- a rectifier is far more likely. .


Power transformers have to be dipped in something very much like varnish to help them have low mechanical noise. Then they are baked- so you can get bubbles. This is not to say that the transformer hasn't failed; to test it all the secondary circuits have to be opened so that there is no load on the transformer whatsoever. If it continues to blow fuses then you know its bad.


The blister on the transformer cover, is something to be concerned about. The "why" more than anything..That's hot!!

Pulling the top on the transformer and doing a "look see", if you can. If it's burnt, it's burnt.. The ol sniff test goes a long way, too, does it smell burnt?
   
Did you pull the valves and see if it will stop blowing fuses.  If it turns on, look to the valves. Is there a chance one blew and that caused a fuse to blow.  Happened to me more than once.
I've lost valves that caused a resistor or two to fail, and the other way around, lost resistors that blew a valves..

If it won't power up, MAKE SURE the fuse is good, (could have blown) pull all the valves and check again, if not, look for a second fuse inside. Then make sure the on/off button didn't go bad.

One visual, the transformer. The on/off, a DMM. Unless you lost a valve it's shop time.. You don't need a schematic, but it can sure help in some cases. Probably no schematics because it was scribbled on a paper bag.. Their not that complicated of a circuit.. No matter who made the amp..The reason there is no information is because there never was, very common in the valve preamp/amp world..

Regard