I have an Akai R2R deck - 4000ds MkII. In the schematic on the service manual it is showing a pair of ICs on the preamp board, but mine has no ICs, but instead two 1312 and one 1647 transistor on each record channel, and one 1312 and one 1647 on each playback channel.
What can I use to replace these 1647 transistors? They look like this, which is not the same as the big power ones when I google it so I'm a little confused:
It seems I can use 1845 for the 1312. Should I just use 1845s flipped backwards?
I replaced the eight c458 transistors with 1845 already.
What can I use to replace these 1647 transistors? They look like this, which is not the same as the big power ones when I google it so I'm a little confused:
It seems I can use 1845 for the 1312. Should I just use 1845s flipped backwards?
I replaced the eight c458 transistors with 1845 already.
For future googlers: this was resolved successfully with some recycled 2sc1845 and 2sc1815 (installed backwards for the 1312s) transistors from a blown receiver.
The Akai deck was built with a straight flush of transistors that are on the **** list of known bad transistors from the 70s that age poorly.
Swapping them out resolved a maddening discrepancy in gain between the channels, where one was fully 3db lower.
The Akai deck was built with a straight flush of transistors that are on the **** list of known bad transistors from the 70s that age poorly.
Swapping them out resolved a maddening discrepancy in gain between the channels, where one was fully 3db lower.