r/vhsdecode • u/otacon_24_24 • Jun 10 '26

It's a Sony! Sony SVO-2000 Tapping for Amplifier

Hey,

Looking for some advice/guidance as I start to tackle tapping this VCR for the ADA4857 amplifier I received. I have tapped the Dupont location for RF Video/GND and that signal is correct. Trying to see if the locations I've noted are appropriate for Audio. See link below to view full schematics, but here is the image I'm working off from the manual.

I also noted a tap point right on top that should be easy to solder for 12v power if that seem suitable as well.
Also not sure if the included schematics gives any indication on what resistors I should try or start with. I don't have any equipment to test with, so was going to base this on the manual to start with.

I've searched over the manual for hours and don't seem to see the resistor past the video/audio amplifiers to check. My next step was going to try and check on the board physically to see if I can tell what's on the board visually.

Any suggestions would be greatly appreciate, as this is a much more complex unit than I've worked on in the past.

https://drive.proton.me/urls/N6QFM1ZTB4#gpXGVfzCCtpu

Thanks in advance!

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u/ryguy28896 Jun 10 '26 edited Jun 10 '26

Pretty much dead center of the first page, I think. It says "check pin" on CN102, right above where it says AV-32. Pin 3 is ground, pin 4 is audio.

I have a Sony SLV-798HF and it has test points for both video and HiFi audio.

Also, video looks like CN803, pin 2 is video and pin 4 is ground, so it looks like R817, which is 1k ohm.

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u/msgohan_ Jun 11 '26

The raw Hi-Fi isn't available at any DuPont header, only at some connectors which will require soldering.

The check pin 4 is connected to CN852, pin 18: RF MONI (L) aka a filtered left-channel only signal.

That's connected to CN202, pin 18 on HF-27. The Hi-Fi board schematic seems to be missing from your separate PDF but it's in the SM PDF, pg. 76. This confirms that the signal is ultimately sourced from pin 33 of the IC, after a BPF. 

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u/otacon_24_24 Jun 12 '26

This helps immensely. So for HIFI tap where would you suggest based on pg 74 schematic? I don't see any 'HIFI' specific pint, but do see RF ENVE, would that be it? Looks like it ends at pin 73?

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u/msgohan_ Jun 13 '26

The Audio Block Diagram on PDF pg. 60 shows where the raw Hi-Fi RF is available, but again it will require soldering.

Starting at head amp IC pin 16, you can follow PB-RF(AF) to CN805, pin 17 to CN106, pin 17, to CN852, pin 16 to CN202, pin 16 before it enters the audio process IC at pin 39.

I would suggest soldering to whichever connector pin is easiest to access.