Bose 601 Series I Original Fuse

[script56]

hello. i have a pair of 601 with a problem with no tweeter output. bought them without knowing this, but figured if anything was wrong i could fix it. the fuse in the pic reads norelco 211 holland.

anyone know if this is called a fuse and can i get a replacement at radio shack.

also would this bad fuse make the tweeters not work or is it caps i need to replace?

I believe you can see in the last pic that the fuse is broken on the inside...

 

[dshoaf]

This is actually a light bulb. It is hooked up in series with the tweeters and is used as a protection device in this application. The bulb, when more current flows through it, will heat up the filament that you see rolling around in there. When the filament glows, its resistance goes up, reducing the drive to the tweeter(s), in your case.

From the nice close up pictures, I'd suggest that the filament failed at the joints where it attached to the suspension arms. General failure mode is for the filament to separate when it had too much current flowing through it. Might these speakers have been bounced around in some way that you might know of?

Anyway, replace the light bulb with something of similar rating. The specs should be pressed into one end of the contacts. Of course, if you want, you can bypass it as long as you don't push the speakers hard.

One last detail, the first few months of shipment of the Series I's did not have this bulb protection device. Bose supplied retrofit kits for warranty service stations to installed them on all 301 and 601 Series I speakers that came in for repair - usually for tweeter replacement. You can tell if they were installed at the factory as the wires will be wire-wrapped tightly to those pins you see. Most bench techs didn't have the rather expensive wire wrapping gun that Bose recommended they buy so they typically soldered them in!

Cheers,

David

 

[JohnMichael]

This is actually a light bulb. It is hooked up in series with the tweeters and is used as a protection device in this application. The bulb, when more current flows through it, will heat up the filament that you see rolling around in there. When the filament glows, its resistance goes up, reducing the drive to the tweeter(s), in your case.

From the nice close up pictures, I'd suggest that the filament failed at the joints where it attached to the suspension arms. General failure mode is for the filament to separate when it had too much current flowing through it. Might these speakers have been bounced around in some way that you might know of?

Anyway, replace the light bulb with something of similar rating. The specs should be pressed into one end of the contacts. Of course, if you want, you can bypass it as long as you don't push the speakers hard.

One last detail, the first few months of shipment of the Series I's did not have this bulb protection device. Bose supplied retrofit kits for warranty service stations to installed them on all 301 and 601 Series I speakers that came in for repair - usually for tweeter replacement. You can tell if they were installed at the factory as the wires will be wire-wrapped tightly to those pins you see. Most bench techs didn't have the rather expensive wire wrapping gun that Bose recommended they buy so they typically soldered them in!

Cheers,

David

Very correct and when I sold Bose along with JBL and AR's including AR9's many partiers came in with concern that they saw flashes of light from the ports and wondered if their speakers were on fire?

 

[dshoaf]

Very correct and when I sold Bose along with JBL and AR's including AR9's many partiers came in with concern that they saw flashes of light from the ports and wondered if their speakers were on fire?

Cute. Can't say I had anyone complaining about that. The bulb protection feature was an excellent and reliable method of keeping people out of my repair shop, for sure.

BTW, instead of hiding the bulb, UREI studio monitors such as the 813, 811s, and 815s, used the same light bulb method but placed them behind colored bezels on the front panel so that the engineer would know when he was approaching the limits of the speakers. Worked great.

Cheers,

David