[Solved] Sanken SI-1125HD hybrid schematic (Sony STR-313L) - Page 1
Forum section: electronics / repair

author: shakalnokturn
author_rank: Super Contributor
timestamp: April 21, 2021, 01:13:53 am
content: I'm working on a Sony STR-313L with distorted sound on left channel.Found the datasheet for the Sanken amplifier hybrid that does include a schematic but the .pdf is so low quality that it's not much use.Anyone out here have a usable copy that would save me some time in reverse engineering?

author: shakalnokturn
author_rank: Super Contributor
timestamp: April 21, 2021, 10:11:34 pm
content: Before poking around inside the removed hybrid the component tester on my Hameg scope was clearly showing differences between channels.Not really expecting any reply here I went and drew the schematic with values from the good channel, funny thing is they're both showing the same thing now on the component tester...Anyway just in case it's of future use I've attached other photos and schematics found while searching and a zip file with my notes and schematic.(Beware zip files may contain viruses!)Time to fit it back in the amplifier and check if it has self repaired.

author: shakalnokturn
author_rank: Super Contributor
timestamp: April 21, 2021, 10:54:30 pm
content: Finally caught the glitch before re-fitting it for nothing, the emitter bonding of the upper output transistor had fused into a small ball, almost making contact.An external isolated TO-220 it will be...

author: shakalnokturn
author_rank: Super Contributor
timestamp: April 22, 2021, 11:03:07 pm
content: A few more pictures as a follow-up.A quick check with random transistors there's room to fit four TO-247 packages besides the hybrid if things come to the worse.Base and Emitter break-out wires epoxied onto the defective transistor.Reassembled with a 2SD2059 in place of the bad output transistor.Good I/V curve on the component tester between +Vcc and output on the removed hybrid.The amplifier is now working well, without noticeable difference between channels.The MPX trimmer needed readjusting on the receiver to get stereo.Anyone know why the service manual mentions replacing R239 from 13k to 24k when IC201 is replaced?I checked against the voltages given on the schematic with and without muting. The mute line is close to 0V when muted but not close to 5V un-muted (only 2.7V), replacing R239 with 24k allows to get close to 5V, but why replace it only if replacing IC201?Thanks for watching.

author: saleach
author_rank: Newbie
timestamp: November 15, 2024, 07:52:23 am
content: wow... I have the Rotel RX-304 receiver with one distorted channel. I ve tried directly to supply the signal onto IC pins, but it is the same situation. Do you have some advice how to disassemble this IC, and maybe some tips how to proceed with repair? Thanks in advance! Firstly I would check output transistors, but I m little bit concerned about the glue that is put onto components...At the end if I understood what you did is that you bypassed the original defective transistor with the external one?

author: saleach
author_rank: Newbie
timestamp: November 15, 2024, 11:39:06 pm
content: I check the transistors, failed was the right one, down. With some reverse engineering, I found what was the type of TR and BCE pinout and put outside one BD243C. It s alive!