Hi friends,
I have 2 units of k 4040, one assembled, other planning to do shortly. How ever last week i cranked up volume to the max( parasound zpre- pre amplifier),suddenly both the channels started distotrion… i can repair it provided i get assistance, anybody out there to help. Rknnlight@gmail.com- thanks in advance… Raj nair.
Did you check the bias on the tubes?
Can you still adjust them?
Oh yes, i can adjust and corrected it to 0.4 volt, it was working perfectly, and this happened soo suddenly, sounds like the transistor damage in some trans amps. At very low volume nothing appears, but after 10% of volume its crackling. The best part is, its happening exactly the same way in both channels, which means something wrong is common for both cahnnels. I changed all the tubes from my new kit, but its the same. Thank you very much for your response. Waiting for further help.
By any chance it can be the output transformers ?? But then the crackling happens exactly same as in both channels!!
Checked the output transformers, they are ok…
Reed relay can get damage?? I cant find any other problem on the board yet…
Have you checked for all of the voltages are they present and correct?
I know you said you changed all of the tubes but I am wondering about V11.
This tube is common for both channels it also hidden behind the covers.
All the voltages are correct, i guess i got it, C 30 is leaking, let me change it and will inform you…
No still the same…
Have you tried to change the preamp or maybe just disconnect it?
Just to see if that is the issue?
Oh yes, i switched the pre amp and the speakers as well… now i am going to replace the big caps and try again… its not easy to change the output transformers but done that also…
Sorry but I’m not really sure what to suggest next.
But you maybe on the right path since those caps dry out after awhile.