Class A bias when using 230v for 220v transf.

[Jakobsson]

I am doing some repair on an older amp, Marantz PM80 and i found that the speaker select relays are defective and i fixed that.
Next thing i checked the bias and the service manual says 18mV (50mA) in class AB and when switched in to class A 198mV(500mA).
I started to adjust the AB value from 2 to 18 no problem.
Then i went on to adjust the A value and adjusted from 90 to 200 on one channel but when i was raising the other channel and was very close to 198 the fuses blew.
I realise that class A is putting max load and the fuses is probably very close to the power output.
The fuses are 2pcs of 4A located on the AC rail to the rectifier.
I was looking at the voltages and the only thing that i can see is that the transformer is connected at 220v and i have 230v.
The transformer also got an alternate 240v winding.
Question is move to 240v winding, lower the bias or put bigger fuses in ?

The config are dual 2sa1256/2sc3182 in each channel.

Pelle

[AndrewT]

Hi,
I used F4A fuses in a Ksa100 Klone biased to 2.6A

I wonder if the fuse blowing is down to an oscillation starting as the bias was increased?