need help with krell ksa 100

[nugent4151]

Just got this amp from a friend. Everything works fine except for the left ch. I would like to fix it but don't know where to start. Any help would be appreciated.

[PhaseLockLoopy]

KSA is not a complex amplifier http://www.solaris.no/electronics/po...ell-ksa100.jpg

However, doing amplifier repairs - you do need some basic tools and some experience

An oscilloscope - a multimeter and a static 8Ω dummy load rated at 200W is preferable - as checking final repairs on speakers can be expensive if the amplifier goes into "critical breakdown" during test.

A visual inspection of the interior and the boards are always good before making any advancement on circuitry.

All the basics - check wiring - health of power supply - fuses - leaks from capacitors etc.

Check over interior of housing for any bits (metal/
left overs from a component that errupted) -

If you are not the original owner of the amplifer - check for obvious re-work that isnt consistent with the work of the original manufacturer. (I have met some amplifiers that have the brand name on the front - but someone loaded the transformer and PCB from another make) - do check originality of parts against the schematic.

Check the PCBs for burns - discolouration of PCB - burnt components - smoke residue - flash marks - any foreign bodies got in there (amazing what can fall through vent holes or is left behind after the initial manufacturing process) - any wires fallen off? -

Usually the visual inspection provides some forensic on age and use of an amp
provides some clues on how and why it failed.

My advice is - dont go thinking about the complicated -- always approach from the simple.......... it's also less expensive that way.

[nugent4151]

Thankyou for the quick reply. I will carefully check the interior for anything unusable.

[PhaseLockLoopy]

Once you're satisfied you dont have the remains of Chernobyl - a railway track parked across the bias chain and you do have a Krell and not a Yamaha in a Krell chassis, then we can start getting techie

[nugent4151]

Hi PhaseLockLoopy,
I got this amp from a friend who had it for over ten years powering his Quad speakers. He never had it serviced or opened. He gave it to me if I'll haul it off. So I think it's the original parts inside. Everything works fine except for the left ch.
Haven't open it yet. Don't know where to start unscrewing.

[tiefbassuebertr]

From KSA-100 there are different versions - go to post 26 about
Older Krell Schematics
for pictures of the different versions I know. From one of this versions you will also find a schematic that I have create.

[nugent4151]

Hi tiefbassuebertr,
I'll try to tackle this amp this weekend when I have time. Hopefully I can get this up and running with your help. I will post again after I open it up and look inside. Again thankyou very much.

[nugent4151]

After opening up, cleaning it and measuring it with the mutimeter, the only that look bad is the relay switch (I think that is what its called). It is black, about 1"by 1 1/2" inch,and has 4 prongs. One of the prongs that has the (on)letters connects to the red speaker plugs. Can you please tell me where I can buy this?

[PhaseLockLoopy]

Sometimes a failure like that is the consequence of some other failure

[nugent4151]

When I hook the amp to the speakers it works but I have to play around with the red wire that connects to the left speaker plugs. I think the leg form the switch(I think that is what it's call) is loose that's why I want to replace it or I could open the switch and try to fix the leg that is loose.