Oh No, something went wrond with my REF 40

[TOGA]

Hi,

I don't know how long this has happened, but it work normally and sonically unnoticeable. May be it related to to pop noise it made long time ago but now
disappeared.
One leg of the white Multicap capacitor under the left hand side R-core transformer in power supply unit broken and pop that white cap up, with
black burnt on circuit board.
I just found out while I opened the top to clean internal with brush.

Just curious why the unit still functioning well and sound normal to me despite of one
burnt and broken capacitor.

Must contact dealer immediately

TOGA

[chessman]

TOGA, that is a shame! I would not use it until repaired.

[TOGA]

here is a pic in case you may want to see
Toga

https://www.yousendit.com/download/T...cHY1aWJtcXRVag

[New guy]

It looks like a bypass cap that is now open. An open bypass cap will still allow the circuit to operate depending on what it's bypassing. It's commonly used to bypass large capacitors and diodes/rectifiers. If the bypass cap was shorted then a fuse would blow. It looks like a pretty easy problem to fix.

[TOGA]

Thanks new guy, so after the repair, I hope the sonic quality remain same as when it left factory, but hey, even with a blown cap I can't detect it by ear, so I guess after repair I should not be able to detect anything negative. By the way, to repair that cap I guess the unit must be almost totally disassemble from the chassis, so it will not be handcrafted in USA anymore. I guess if this happen inside some of ARC power amps such as 610T, R750, the owner might use it till end of product lifetime without knowing this happening, If I did not open the top to clean the dust, I wouldn't know it happen too. To cheer my ears up that I cannot hear anything, may be because of the over-engineering of ARC power supply in REF40 that make it still work quite well with the remaining bypass caps.

Toga
and here is another picture
https://www.yousendit.com/download/T...R0ZreEI4SjhUQw

[Elberoth]

Pretty easy fix, seems that your tech will have to remove the circut board though.

The amp still works since as noted earlier - it is only a bypass cap. That cap was not made by ARC (it is a MultiCap) and probably must have had a manufacturing defect of some kind.

[TOGA]

ok, now so I can have beautiful music until dealer come to get it to have it repaired.
thanks

toga

[Robert_Anderson]

I think your ARC dealer has an obligation to loan you a demo so that you can send it back to ARC for repair, and hopefully another round of bench tests to ensure the unit is in good shape.

[tdelahanty]

Ask your technician to measure the voltage across the bad cap, also determine the voltage rating of the bad cap. If there is enough room you may want to install a cap that has a higher voltage rating.

Tube products are notorous for this type problem, due to their high voltage levels there is not much of a satety factor. Solid-state designs have lower voltages, it is good and accepted design practice to rate caps at twice the circuit voltage. This ensures long life.

[microstrip]

Elberoth was spot on. It will be very simple to fix. Apparently it is a bypass capacitor that exploded due a manufacture defect. As the preamplifier is working perfectly and teh capacitor seems located near the four rectification diodes most probably you will not need to change nothing else, it is just supply bypass.

What maybe Elberoth does not know is that the REF40 (at less my unit) has bottom and top covers (a la conrad johnson ...) and the technician will be able to replace the capacitor without disassembling anything - just taking the screws of the covers out. Maximum worktime - 15 minutes for a lazy guy.

BTW, Please use only a capacitor supplied by ARC for this place. Please ...