advice on substitute transistors.

it turns out the 2955 were plug and play replacements for the AU103 atleast in this circuit.
i didnt even have to adjust any trimmers:) and the signal looked good enough:) 1khz looked perfect and some small defects at 10khz.
but you know what?! the noise didnt go away. only thing improved was that the amp no longer randomly goes into DC:)

so i thought what the hell is wrong with this thing and i was about to throw it under a bus:)
When i by accident noticed a bad ground connecion to chassis on the noisy amp board, impossible to see or meashure it. i found it while having the board loose and wiggling it while playing music.
i soldered new wires from both amp boards and secured them to the chassis.
and Voila! the thing works like never before!
 
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to wrap this up if any ever look here and going to fix one of these up. be prepared for hard time. as in "1965 handbuilt in germany" hard time:) man almost impossible to work on compared to the modern japanese 1970´s stuff:) just to get the heatsinks out i had to drill the rivets on the VAC selector to get to the screws i needed. only one example of many.
also there is some variations of the RTX400 it says "FM-MX Stereo" and have a stereo indicator text printed on the glass where the lamp would shine through.
but mine has a mono radio with no stereo lamp mounted. probably since stereo FM wasnt broadcast in sweden at the time? so they probably thought no one would notice if they threw in a cheaper radio for the swedes :)
its sold in sweden judging by the sellers sticker on the back.

my receiver didnt match the schematic at several points. besides the mono fm that is.

i will post this thread in the original RTX400 thread so it sort of ends here.
 
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