C-Audio RA501

[blakeyboy]

I have a RA501 with a really annoying habit- it clicks on and off for 5-10 mins from cold,
then is fine. Does anyone recognise this fault and / or have a schematic?
I've fixed hundreds the other RA and SR series over the years,
but the RA501 is a completely different design...

cheers

b

 

[blakeyboy]

Fixed.

Usual C-audio thing- capacitors a bit smaller than what would have been better- RA3001's for example run hotter than they should until you pull the 47uF and replace it with a 470uF on the dc supply to the fan.

In the RA501, 470uf x2 on the supply to the twin 15v regs- I suspect ripple/ low headroom moves the 15v rails about when cold. Probably ok when new, but esr rising a bit over the years and this is a problem.
Added a pair of extra 470's and that was that. I didn't change the existing caps for a pair of 1000's
since the design makes getting the boards out a right pain- designer should have been shot....

Still would like a schematic though....!