[jimbobuk]

I got home tonight and just happened to look and notice that the light was off on my Stax SRM-717, i assumed it'd had had the power switch turned off, but sadly it hadn't.

I've checked everything, moved it out so i can get a good look at it, checked the fuse in the power cable, nothing.

It just doesn't power on, no light.

I've done a bit of searching and heard that most folks don't recommend leaving it on all the time, I've always thought it was the preferred thing to do with hifi equipment so mostly i've had mine on all the time. It gets hot but not THAT hot, well now its not working its gone cold

I'm based in the UK, and brought it from Simply Stax.. the site is down now with phone numbers to phone for support.

What's the verdict on this kind of symptom, i've shined a torch inside the thing and can't see anything noticably fried/burnt, I don't fancy really taking it apart as there must be some high voltage things inside. Is there any chance that there is a fuse inside that can blow and just be replaced.

Has anyone had their 717 repaired, preferrably in the UK but i'd be up hearing about any experiences at this point.

Further reading and i notice that people don't recommend leaving headphones attached, potentially doing damage to them. Well i've left my Omega's attached for a good while now, and i've not had chance to use them lately either. I'm now worried that they could be damaged too, though am hopeful that they wont be.

Bah, frustrating... Any one got any advice?

 

[spritzer]

It could be as simple as a fuse blown but that usually happens for a reason.

I would remove the top cover (remove the screws on the sides) and look inside. The fuse is at the back, above the IEC input, but try notice any burn marks or a bad smell. Amps with high voltage rarely go silently into the long night so there might be blown caps or resistors though you would probably have smelled that immediately as you walked into the room.

If the amp is well ventilated it's fine to leave it on all the time but it is a good idea to use compressed air and blow all dust out of the amp every year or so. The phones are also fine if you use a dustcover and it's also wise to unplug them from time to time and discharge the diaphragm by shorting out the pins on the plug.

Symmetry is the UK distributor so they handle all repairs. Here is their contact information on the Stax site.

 

[jimbobuk]

Thanks for the info. I'd already got Symmetry's number and may give them a call tomorrow.

I followed your advice and carefully took the lid off. Peeking around inside no obvious signs of anything melting.. I could see 3 clear fuses, hard to see anything inside, but the one nearest to the power socket appears to have snapped/blown.

I'm uploading pictures of the insides as i type. The thing is the access to this blown fuse looks very difficult, its right next to what i assume is the transformer, it looks like i could get it out and put in a replacement, but i assume the entire transformer, or the entire power supply board should be removed for this.

What i'm worried about is something in there holding on to some serious charge.. is it just the capacitors that you have to worry about, its been a while since studying physics but a transformer shouldn't store charge should it?

Also it has what looks like a cirtcuit board on top, is any of this removable to gain access?

The thing is it has had a bit of movement behind the unit, but i'm guessing if anything innocent caused the blown fuse it may have just been a power surge?

I'm surprised to read in simplystax's summation of why he closed down, that reliability of the 717 was one of the issues.. i got the 717 instead of the 007 to avoid the fiddlyness of tubes and assumed it'd be far more robust. What exactly are the known issues that can cause problems with the 717?

Cheers

 

[jimbobuk]

here's the photo set, i'll annotate some of the images to hilight areas.

Broken Stax SRM-717 - a photoset on Flickr

here's the offending fuse though its hard to see, let alone shoot to show it clearly, but viewed larger i think you can see that this is broken/blown.

Flickr Photo Download: DSCF1281

 

[jimbobuk]

this photo

has detailed notes here

Overview on Flickr - Photo Sharing!

 

[spritzer]

That fuse is indeed blown but I don't see any damage anywhere else so it could be a power surge or a small short circuit due to dust that blow the fuse. The transformer doesn't hold any charge, the capacitors do that. The small circuit board on top of the transformer is for aesthetic purposes only and is simply stuck to the top of it. I would start off with a new fuse and if it blows again then the amp needs service.

I haven't heard anything about problems with the 717 but some of the information on the Simply Stax site is wrong and some is even absurd so take it with a grain of salt. A bad batch could have been shipped to the UK but there is nothing wrong with the design.

 

[jimbobuk]

have you done any repairs like this.. finding a fuse to match may be tricky, i'll have a look though.. perhaps success this weekend.

Not sure how best to try and prize the fuse out, hard to get access.

 

[kevin gilmore]

Fuse definitely blown, getting the old one out is certainly easy,
putting a new one in probably not so easy, get a surgical pliers and
it will be a snap.

It is interesting to note that i have a picture of a unit almost exactly
like this except it is labeled as a srm-727, so this is an extremely
new unit with probably a slightly older front panel.

Put in one and only one new fuse of the same rating. If it instantly
blows, then stop. However some of those units for 220 volts initially
shipped with .5 amp fast blow fuses, and that is just not enough to
handle surges.

 

[jimbobuk]

Thanks i will give it a try.. to be honest I agree getting it back in may be tricky... to get out do i just need to use a screwdriver to lever it out from the centre of the fuse? Trying to pull at it gently and the whole board its on moves slightly so i don't fancy putting too much force into it.

with pliars do you imagine gripping in the centre to let you position and then pull into place... I can't imagine where to get fuses of this kind from, it'll be clearer when i can get a better look at it after removing it.

Thanks for your help guys..

 

[Duggeh]

My 717 is a UK bought unit from Symmetry. I've been running it basically 24/7 for nearly 2 years and no problems. If your's goes again after a fuse change then give Symmetry a ring and see what they have to say. Their warranty period is pretty long afair.

 

[jimbobuk]

yep, will do. Its been nearly as long for me.. its just doing the fuse swop that will be interesting.. shame there aint no instructions/guide online.. i don't wanna break anything.

Cheers

 

[spritzer]

Quote:

Originally Posted by jimbobuk /img/forum/go_quote.gif have you done any repairs like this.. finding a fuse to match may be tricky, i'll have a look though.. perhaps success this weekend. Not sure how best to try and prize the fuse out, hard to get access.

I have done this a number of times on different equipment and you should be able to get the fuse from any hardware/electronics store. The rating is stamped on either end and but I can tell you from the pictures that this is a fast blow fuse.

When the fuse holder is in a tricky place I use needle nose pliers to position one end of the fuse in its socket and then press the other end home with a flat screwdriver through only touching the metal part.

 

[jimbobuk]

brilliant. Makes sense. What is your idea for an equivalently safe way of taking the fuse out, i don't want to break the central clear core trying to lever it out, but i dont see any other way of getting access to it.

 

[spritzer]

Quote:

Originally Posted by jimbobuk /img/forum/go_quote.gif brilliant. Makes sense. What is your idea for an equivalently safe way of taking the fuse out, i don't want to break the central clear core trying to lever it out, but i dont see any other way of getting access to it.

Place a flat screwdriver behind the fuse at one end and use it to leverage it out of the socket. Go from end to the other to lessen the stress. Glass is pretty strong against a force like that but be gentle and it should pop out of the socket.

 

[jimbobuk]

thanks, will try later