Sony-rcp/docs/discovery-notes.md

Discovery Notes

This file records hands-on observations separately from manual-derived facts. Treat these as bench notes: useful and current, but still worth rechecking with photos, continuity tests, and instrument captures.

2026-05-13 - RCP-TX7 10-Pin Power and Cable

Observed on the RCP-TX7 10-pin remote connector/cable during restoration work:

• Pin 9 confirmed as ground / DC return.
• Pin 10 confirmed as power input.
• Cable color for pin 9 / ground: brown.
• Cable color for pin 10 / +12 V power: brown-white.
• Cable colors for pins 1-8 have been continuity-mapped; see the working cable map below.
• Yellow and yellow-white conductors are present in the cable but did not map to connector pins during continuity testing.
• With power present on pins 9 and 10, the panel shows a green PANEL ACTIVE light.
• The inside of the 10-pin cable contains 12 wires total.
• Three of those wire groups are twisted pairs.

Immediate implications:

• The bench result agrees with the RCP-TX7 and CCU-TX7 manual pinout for pins 9 and 10.
• The 12-conductor cable construction suggests not every conductor maps one-to-one to the 10 connector pins; shielding/drain, duplicated grounds, or paired signal returns may be present.
• The three twisted pairs are likely important candidates for serial data, composite video, and/or power/ground pairing, but this should be confirmed by continuity testing rather than color or twist assumptions.

Working Cable Map

This table combines the manual-derived pin purpose with hands-on color mapping. Rows marked confirmed have been checked on the current cable/panel under test.

Pin	Purpose	Cable color	Status	Notes
1	Spare / unused	red	confirmed	No function shown in service manual.
2	VBS / composite video X	black	confirmed	1.0 Vp-p composite video input to RCP.
3	VBS / composite video ground	green	confirmed	Video reference/ground.
4	Serial data, RCP to CCU/camera	orange	confirmed	RS-232C-based data direction.
5	Serial/data ground	blue	confirmed	One of two serial/data grounds.
6	Serial/data ground	grey	confirmed	One of two serial/data grounds.
7	Serial data, CCU/camera to RCP	purple	confirmed	RS-232C-based data direction.
8	Spare / unused	purple-white	confirmed	No function shown in service manual.
9	DC return / ground	brown	confirmed	Confirmed as ground on current cable.
10	+12 V remote power input	brown-white	confirmed	Confirmed as power input on current cable.

Unmapped Cable Conductors

The cable contains two additional conductors that did not show continuity to the 10 connector pins during the current test:

Conductor color	Current status	Notes
yellow	unmapped	May be shield/drain-related, spare, broken, or connected only at one end.
yellow-white	unmapped	May be shield/drain-related, spare, broken, or connected only at one end.

Recheck these against connector shells, shield braid/drain, cable strain relief hardware, and both ends of the cable if accessible.

Suggested next observations to capture:

1. Connector orientation photo showing pin numbering reference.
2. Wire color list, including which colors form each twisted pair.
3. Confirm whether yellow and yellow-white connect to shield, shell, or one end only.
4. Resistance between pins 5, 6, and 9 with the cable disconnected.
5. Scope/meter idle voltage on pins 4 and 7 relative to pins 5/6 and pin 9.