I have been trying to bring an RM Italy KL-500 back to life. Originally it had 4 x MS1051 transistors. When they blew Audioshockwave offered me some MRF453 (large case MRF455 transistors) the original KL-500 came with 4 x MRF455, then 4 x SD1446, then MS1051, then back to SD1446.
So I figured people swap SD1446 in place of MRF455 all the time, and the MS1051 was being used in place of the SD1446, which was being used in place of the MRF455, so by that logic the MRF453 (or MRF455 for that matter) should drop right in.
And it is did, I hit it with around 15 PEP from a Roadpro Titan II 485, which has the single final, 2sc1969.
Talked good for a few minutes, got good reports, THEN it started putting out about 1/4 to 1/3 of the power it used to put out. I shut it down and disconnected everything
Upon inspection I found that resistor R28, was burned, and had a resistance of around 0.58 ohm Also it is a 1 watt part, the parts list from RM Italy calls for a 2 watt 100 ohm resistor...
This resistor sets between the output transformers. So it is for balancing I would guess. (I am still new to amps)
Part of the problem I see here is that RM Italy says to use a 2 watt part, but the part being used is clearly a 1 watt part... maybe this is the issue? But I would think it would have blown with the MS1051 transistors.
Oh well fun fun fun right.
http://rmitaly.com/download/manuals/KL500-manual_rel_500.pdf
