BIO-RAD 3000Xi: Difference between revisions

(19 intermediate revisions by the same user not shown)

Line 38:

!Module!!Function (inferred)!!Status

|-

|[[#OEM No. 125B|OEM No. 125B]]||''~~TBD~~''~~||Not yet documented~~

|[[BIO-RAD 3000Xi#OEM No. 125B - CPU Control Board|OEM No. 125B]]||CPU Control Board||'''Documented''' below

|-

|[[#OEM No. 126C|OEM No. 126C]]||~~''TBD''~~||Not yet documented

|[[#OEM No. 126C|OEM No. 126C]]||User Interface Keyboard/Displays||Not yet documented

|-

|[[#OEM No. ~~127A —~~ HV Controller Board|OEM No. 127A]]||HV controller / regulator / telemetry||'''Documented''' below

|[[BIO-RAD 3000Xi#OEM No. 127 .28A.2FB.29 .E2.80.94 HV Controller Board|OEM No. 127A (A/B)]]||HV controller / regulator / telemetry||'''Documented''' below

|-

|[[#OEM No. 128B|OEM No. 128B]]||''TBD''||Not yet documented

|-

|[[#OEM No. 130C|OEM No. 130C]]||~~''TBD''~~||Not yet documented

|[[#OEM No. 130C|OEM No. 130C]]||HV Filter/Monitor board||Not yet documented

|-

|[[#OEM No. 131A|OEM No. 131A]]||''TBD''||Not yet documented

Line 60:

==High-Level Block Diagram==

<pre>

┌─────────────────────────────────────┐

│ Front-Panel ~~Microprocessor~~ (μC) │

│ Front-Panel Board (OEM No. 126C) │

│ (LCD, keypad, ~~programming~~ logic) │

│ LCD + driver, keypad, LED displays │

│ + display/keypad control logic │

└────────────────┬────────────────────┘

│ ribbon (J7 ↔ J-2)

▼

┌─────────────────────────────────────┐

│ OEM No. 125B — CPU Control Board │

│ MC6809 CPU · MC6821 PIA · 2×6840 │

│ EPROM "Xi 4.0" · batt-backed SRAM │

└────────────────┬────────────────────┘

│ ribbon (J-16)

│ ribbon (J-3 ↔ J-16)

▼

┌─────────────────────────────────────────────────────────┐

Line 73:

Line 80:

│ │ Opto-iso. │─▶| TC4584 │─▶│ AD7543 12-bit │ │

│ │ rcv (TLP) │ │ Schmitt │ │ serial-in DAC │ │

│ └────────────┘ └────────────┘ ~~└────────┬────────┘~~ │

│ └────────────┘ └────────────┘ └───────┬─────────┘ │

│ ▼ │

│ ┌────────────────────┐ │

Line 80:

Line 87:

│ └─────────┬──────────┘ │

│ ▲ │

│ ┌────────────┐ ┌────────────┐ ~~┌───────┴────────┐~~ │

│ ┌────────────┐ ┌────────────┐ ┌──────┴─────────┐ │

│ │ Opto-iso. │◀─│ AD654 V/F │◀─│ LF353 / LM358 ~~│◀────┼──~~ HV feedback

│ │ Opto-iso. │◀─│ AD654 V/F │◀─│ LF353 / LM358 │◀──┼── HV feedback

│ │ tx (TLP) │ │ converter │ │ signal cond. │ │ (J-13/J-14)

│ └────────────┘ └────────────┘ └────────────────┘ │

│ │

│ Protection: LM358 comp. → TC4013 latch → IR3M02 SD ~~◀───┼──~~ J-15

│ Protection: LM358 comp. → TC4013 latch → IR3M02 SD ◀──┼── J-15

└─────────────────────────────────────────────────────────┘

│

Line 92:

Line 99:

transformer → rectifier/multiplier → output jacks)

</pre>

----

==OEM No. 125B - CPU Control Board==

[[File:BIO-RAD_OEM_NO_125B_Top.jpg|thumb|right|300px|OEM No. 125B — top of board]]

The '''OEM No. 125B''' is the system CPU / control board — referenced in the [[#High-Level Block Diagram|block diagram]]. It runs the instrument firmware, drives the [[#OEM No. 126C|OEM No. 126C]] front-panel board (LCD, LED readouts, keypad) over J-2, and commands the [[#OEM No. 127 (A/B) — HV Controller Board|OEM No. 127]] HV controller over J-3 — sending the 12-bit DAC setpoint and reading back the voltage / current PWM telemetry and circuit-status lines. Run parameters are retained in battery-backed RAM. The board is built around the Motorola 6800-family set (MC6809 CPU, MC6821 PIA, dual MC6840 timers). Date codes place it at 1988; the EPROM is hand-labelled firmware "Xi 4.0".

===Active Components===

{| class="wikitable"

!Ref!!Part!!Function

|-

|'''M1'''||Motorola MC6809P||8-bit microprocessor — main CPU

|-

|'''M6'''||Motorola MC6821P||Peripheral Interface Adapter (PIA), two 8-bit parallel ports — front-panel keypad/display I/O and the J-3 handshake to the 127 board (HV-enable, DAC clock/data/strobe, circuit open/shorted/unknown status)

|-

|'''M4, M5'''||Motorola MC6840P (×2)||Programmable Timer Module, three 16-bit counter/timers each — volt-hour / run timing and capture of the voltage- and current-PWM telemetry from the 127 board

|-

|'''M2'''||Hitachi HN27256G-25||256 Kbit (32K×8) UV-EPROM — program store; windowed, V<sub>PP</sub> 12.5 V, hand-labelled "Xi 4.0"

|-

|'''M3'''||Toshiba TC5564APL-15||64 Kbit (8K×8) static RAM — work / settings RAM, battery-backed by BAT1

|-

|'''M7'''||Signetics CK2605||FPGA — system glue logic (address decode / control sequencing)

|-

|'''M11'''||Hitachi HD74LS640P||Octal inverting bus transceiver — data-bus buffer

|-

|'''M12'''||Motorola MC74HCT240||Octal inverting 3-state buffer/line driver — address / control buffer

|-

|'''M8'''||Toshiba 74HC138AP||3-to-8 line decoder — address decode / chip selects

|-

|'''M9'''||Toshiba TC74HC4020P||14-stage binary ripple counter — clock division / timing

|-

|'''M14, M15'''||Toshiba TC74HC132P (×2)||Quad 2-input NAND Schmitt trigger

|-

|'''M18, M22'''||Toshiba 74HC00AP (×2)||Quad 2-input NAND gate

|-

|'''M16'''||Toshiba 74HC08AP||Quad 2-input AND gate

|-

|'''M17'''||Toshiba 74HC14AP||Hex Schmitt-trigger inverter

|-

|'''M10'''||Seiko S-8054ALR||Voltage detector — power-on reset / low-voltage supervisor

|-

|'''M21'''||National Semiconductor LM358N||Dual op-amp — analog signal conditioning / comparator

|-

|'''M20'''||Maxim ICL7660CPA||Switched-capacitor voltage converter — generates the −5 V rail (TP3) from +5 V

|-

|'''M19'''||Toshiba TDG2002P (TD62002)||7-channel Darlington sink driver array — drives buzzer / indicators / low-current loads

|}

===Clock & Configuration===

*'''X1''' — 4 MHz crystal (MC6809 ÷4 → 1 MHz E/Q bus clock), with C1/C2 loading trimmers

*'''JMP1''' — 3-position configuration jumper

*'''BAT1''' — lithium coin cell, backup for the TC5564 SRAM

*'''M13''' — unpopulated 8-pin position

===Connectors===

{| class="wikitable"

!Connector!!Function

|-

|'''J-1'''||+5 V power input to the board

|-

|'''J-2'''||Front-panel board ([[#OEM No. 126C|OEM No. 126C]]) — LCD display, LED readouts, keypad (40-pin ribbon)

|-

|'''J-3'''||HV control board ([[#OEM No. 127 (A/B) — HV Controller Board|OEM No. 127]]) — maps pin-for-pin to the 127 board's [[#J-16 Data, Status and Telemetry|J-16]]: DAC setpoint out, voltage/current PWM telemetry in, circuit open/shorted/unknown status

|-

|'''J-4, J-5'''||Small I/O harnesses (3-pin) — function TBD

|}

===Other===

*'''BZ1''' — muRata piezo buzzer (audible alarm / key-click)

*'''Q1–Q5''' transistors, '''D1–D13''' diodes — discrete interface / level shifting

*Test points '''TP1–TP7''', '''+5 V''', '''−5 V''' (from ICL7660), '''GND'''

*An unpopulated 20-pin DIP position sits between M3 and M11

===Reverse-Engineering Notes===

#The MC6809 + MC6821 + dual MC6840 set is a textbook Motorola control core. The two PTMs are well-suited to ''measuring'' the voltage-PWM and current-PWM the 127 board returns over J-3 (gate / capture), and to generating the volt-hour and timed-run intervals for the four operating modes.

#J-3 is wired pin-for-pin to the 127 board's J-16, so the 125B PIA directly drives that interface: HV-enable, DAC clock / data / strobe out; circuit open / shorted / unknown status in. The keypad scan / display strobes go to the front panel on J-2.

#The Signetics CK2605 FPGA (M7) handles glue logic — address decoding and control sequencing — alongside the discrete 74HC138 / HC00 / HC132 gates.

#The S-8054 voltage detector (M10) provides power-on reset and brown-out supervision, gating the CPU and protecting the battery-backed SRAM during power transitions.

#The ICL7660 makes a local −5 V rail for the analog / op-amp section rather than relying on the 127 board's ±15 V.

==~~OEM No. 127A — HV Controller Board~~==

===Items Still to Confirm===

~~This is~~ the ~~analog~~/~~digital control board that bridges~~ the front-panel microprocessor and the high-voltage power module. It accepts a digital setpoint from the μC, generates two PWM drive signals to control the HV switcher, and reports back the actual HV and HC values via a frequency-isolated telemetry path. It also handles fault detection and shutdown latching.

*Identify the J-4 / J-5 harnesses

*Dump the CK2605 (M7) configuration / determine its logic role

*Determine J2 pinout to front panel board

==OEM No. 127 (A/B) — HV Controller Board==

This is the analog/digital control board that bridges the front-panel microprocessor and the high-voltage power module. It accepts a digital setpoint from the μC, generates two PWM drive signals to control the HV switcher, and reports back the actual HV and HC values via a frequency-isolated telemetry path. It also handles fault detection and shutdown latching.<gallery mode="slideshow">

File:BIO-RAD OEM NO 127A Top.jpg|'''127A''' - Top of board, J-16 and optocouplers in bottom left

File:BIO-RAD OEM NO 127A Bottom.jpg|'''127A''' - Bottom of board, cutout under optocouplers in top left for high voltage isolation

File:BIO-RAD OEM NO 127B Top.jpg|'''127B''' - Top of board, J-16 and optocouplers in top right

File:BIO-RAD OEM NO 127B Bottom.jpg|'''127B''' - Bottom of board, cutout under optocouplers in top left for high voltage isolation

</gallery>

===Connector Map===

Line 174:

Line 273:

[[File:BIO-RAD OEM NO 127B Conn J16.jpg|none|thumb]]

J-16 carries four data lines to an on-board [https://wiki.recessim.com/w/images/f/fc/AD7543.PDF AD7543] Digital to Analog Converter (DAC) which selects the voltage generated by the power supply. 0 - 4095 is the valid range to set ~20V to 3000V in 0.7V increments. It also has PWM outputs for voltage and current to monitor actual values and three additional I/O lines to signal Circuit Open, Circuit Shorted and one Circuit Unknown, possibly to signal a ground fault condition per the user manual. This connector goes straight to optocouplers so the control side is isolated from the high voltage side.

====Pin Definitions====

{| class="wikitable"

|+J-16 Pinout

Line 250:

Line 351:

|}

====Timing Information====

File:BIO-RAD 3000Xi DAC Data Capture.png

File:BIO-RAD 3000Xi DAC Data Capture - Enable to Clock.png|HV Enable low to start of data

File:BIO-RAD 3000Xi DAC Data Capture - Clock Timing.png|Clock signal timing

File:BIO-RAD 3000Xi DAC Data Capture - Data Timing.png|Data signal timing, centered within clock

File:BIO-RAD 3000Xi DAC Data Capture - Clock to Strobe.png|End of clock to strobe timing

</gallery><br />

===Active Components===

Line 313:

Line 422:

{| class="wikitable"

!Position!!Part Number~~!!Marking~~!!Output!!Datasheet

!Position!!Part Number!!Output!!Datasheet

|-

|'''REG1'''||~~Fairchild '''μA79M15A''' (Korea)||"μA79M15A UC871x KOREA"~~||'''~~−15 V~~''' ~~analog rail~~||[https://www.ti.com/lit/ds/symlink/~~lm7900~~.pdf ~~79xx~~ PDF (TI)]

|'''REG1'''||7805||'''+5V''' Digital Rail||[https://www.ti.com/lit/ds/symlink/lm340.pdf LM340 PDF (TI)]

|-

|'''REG2'''||~~Fairchild '''μA 78M15''' (Korea)||"μA 78M15 UC8704 KOREA"~~||'''+15 V''' analog rail||[https://www.ti.com/lit/ds/symlink/lm340.pdf 78xx PDF (TI)]

|'''REG2'''||7815||'''+15 V''' analog rail||[https://www.ti.com/lit/ds/symlink/lm340.pdf 78xx PDF (TI)]

|-

|'''REG3'~~'' ''(or REG4)~~''||~~National '''LM340T-12'''||"EM340T12 7812 P+" 8730~~||'''~~+12~~ V''' rail||[https://www.ti.com/lit/ds/symlink/~~lm340~~.pdf ~~LM340~~ PDF (TI)]

|'''REG3'''||7915||'''−15 V''' analog rail

|[https://www.ti.com/lit/ds/symlink/lm79.pdf 79xx PDF (TI)]

|-

|'''REG4''' ~~''(or REG3)''||Fairchild '''μA 78M05''' (Korea)~~||~~"μA 78M05 UC8731 KOREA"~~||'''+5 V''' ~~digital~~ rail||[https://www.ti.com/lit/ds/symlink/lm340.pdf 78M PDF (TI)]

|'''REG4'''||7812||'''+12 V''' rail||[https://www.ti.com/lit/ds/symlink/lm340.pdf 78M PDF (TI)]

|}

~~<div style="border-left:4px solid #f0ad4e; background:#fcf8e3; padding:0.5em 1em; margin:1em 0;">~~

~~'''Note:''' REG3 vs REG4 silkscreen position needs confirmation against the TO-220 part numbers — only the REG1/REG2 silkscreen was clearly visible in image 3.~~

~~</div>~~

===Passive Components===

Line 371:

Line 477:

----

~~==OEM No. 125B==~~

~~''Module not yet examined. Photos and reverse-engineering pending.''~~

==OEM No. 126C==

@@ Line 38: / Line 38: @@
 !Module!!Function (inferred)!!Status
 |-
-|[[#OEM No. 125B|OEM No. 125B]]||''TBD''||Not yet documented
+|[[BIO-RAD 3000Xi#OEM No. 125B - CPU Control Board|OEM No. 125B]]||CPU Control Board||'''Documented''' below
 |-
-|[[#OEM No. 126C|OEM No. 126C]]||''TBD''||Not yet documented
+|[[#OEM No. 126C|OEM No. 126C]]||User Interface Keyboard/Displays||Not yet documented
 |-
-|[[#OEM No. 127A — HV Controller Board|OEM No. 127A]]||HV controller / regulator / telemetry||'''Documented''' below
+|[[BIO-RAD 3000Xi#OEM No. 127 .28A.2FB.29 .E2.80.94 HV Controller Board|OEM No. 127A (A/B)]]||HV controller / regulator / telemetry||'''Documented''' below
 |-
 |[[#OEM No. 128B|OEM No. 128B]]||''TBD''||Not yet documented
 |-
-|[[#OEM No. 130C|OEM No. 130C]]||''TBD''||Not yet documented
+|[[#OEM No. 130C|OEM No. 130C]]||HV Filter/Monitor board||Not yet documented
 |-
 |[[#OEM No. 131A|OEM No. 131A]]||''TBD''||Not yet documented
@@ Line 60: / Line 60: @@
 ==High-Level Block Diagram==
 <pre>
                   ┌─────────────────────────────────────┐
-                  │  Front-Panel Microprocessor (μC)    │
+                  │  Front-Panel Board (OEM No. 126C)   │
-                  │  (LCD, keypad, programming logic)   │
+                  │  LCD + driver, keypad, LED displays │
+                 │  + display/keypad control logic     │
+                 └────────────────┬────────────────────┘
+                                  │ ribbon (J7 ↔ J-2)
+                                  ▼
+                 ┌─────────────────────────────────────┐
+                 │  OEM No. 125B — CPU Control Board   │
+                 │  MC6809 CPU · MC6821 PIA · 2×6840   │
+                 │  EPROM "Xi 4.0" · batt-backed SRAM  │
                   └────────────────┬────────────────────┘
-                                   │ ribbon (J-16)
+                                   │ ribbon (J-3 ↔ J-16)
                                    ▼
     ┌─────────────────────────────────────────────────────────┐
@@ Line 73: / Line 80: @@
     │  │ Opto-iso.  │─▶|  TC4584    │─▶│ AD7543 12-bit   │   │
     │  │ rcv (TLP)  │   │  Schmitt   │  │ serial-in DAC   │   │
-    │  └────────────┘   └────────────┘  └────────┬────────┘   │
+    │  └────────────┘   └────────────┘  └───────┬─────────┘   │
     │                                           ▼             │
     │                                ┌────────────────────┐   │
@@ Line 80: / Line 87: @@
     │                                └─────────┬──────────┘   │
     │                                          ▲              │
-    │  ┌────────────┐  ┌────────────┐  ┌───────┴────────┐     │
+    │  ┌────────────┐  ┌────────────┐   ┌──────┴─────────┐    │
-    │  │ Opto-iso.  │◀─│ AD654 V/F  │◀─│ LF353 / LM358  │◀────┼── HV feedback
+    │  │ Opto-iso.  │◀─│ AD654 V/F  │◀─│ LF353 / LM358  │◀──┼── HV feedback
-    │  │ tx  (TLP)  │  │ converter  │  │ signal cond.   │     │   (J-13/J-14)
+    │  │ tx  (TLP)  │  │ converter  │   │ signal cond.   │    │   (J-13/J-14)
-    │  └────────────┘  └────────────┘  └────────────────┘     │
+    │  └────────────┘  └────────────┘   └────────────────┘    │
     │                                                         │
-    │  Protection: LM358 comp. → TC4013 latch → IR3M02 SD ◀───┼── J-15
+    │  Protection: LM358 comp. → TC4013 latch → IR3M02 SD ◀──┼── J-15
     └─────────────────────────────────────────────────────────┘
                                    │
@@ Line 92: / Line 99: @@
                transformer → rectifier/multiplier → output jacks)
 </pre>
+----
-----
+==OEM No. 125B - CPU Control Board==
+[[File:BIO-RAD_OEM_NO_125B_Top.jpg|thumb|right|300px|OEM No. 125B — top of board]]
+The '''OEM No. 125B''' is the system CPU / control board — referenced in the [[#High-Level Block Diagram|block diagram]]. It runs the instrument firmware, drives the [[#OEM No. 126C|OEM No. 126C]] front-panel board (LCD, LED readouts, keypad) over J-2, and commands the [[#OEM No. 127 (A/B) — HV Controller Board|OEM No. 127]] HV controller over J-3 — sending the 12-bit DAC setpoint and reading back the voltage / current PWM telemetry and circuit-status lines. Run parameters are retained in battery-backed RAM. The board is built around the Motorola 6800-family set (MC6809 CPU, MC6821 PIA, dual MC6840 timers). Date codes place it at 1988; the EPROM is hand-labelled firmware "Xi 4.0".
+===Active Components===
+{| class="wikitable"
+!Ref!!Part!!Function
+|-
+|'''M1'''||Motorola MC6809P||8-bit microprocessor — main CPU
+|-
+|'''M6'''||Motorola MC6821P||Peripheral Interface Adapter (PIA), two 8-bit parallel ports — front-panel keypad/display I/O and the J-3 handshake to the 127 board (HV-enable, DAC clock/data/strobe, circuit open/shorted/unknown status)
+|-
+|'''M4, M5'''||Motorola MC6840P (×2)||Programmable Timer Module, three 16-bit counter/timers each — volt-hour / run timing and capture of the voltage- and current-PWM telemetry from the 127 board
+|-
+|'''M2'''||Hitachi HN27256G-25||256 Kbit (32K×8) UV-EPROM — program store; windowed, V<sub>PP</sub> 12.5 V, hand-labelled "Xi 4.0"
+|-
+|'''M3'''||Toshiba TC5564APL-15||64 Kbit (8K×8) static RAM — work / settings RAM, battery-backed by BAT1
+|-
+|'''M7'''||Signetics CK2605||FPGA — system glue logic (address decode / control sequencing)
+|-
+|'''M11'''||Hitachi HD74LS640P||Octal inverting bus transceiver — data-bus buffer
+|-
+|'''M12'''||Motorola MC74HCT240||Octal inverting 3-state buffer/line driver — address / control buffer
+|-
+|'''M8'''||Toshiba 74HC138AP||3-to-8 line decoder — address decode / chip selects
+|-
+|'''M9'''||Toshiba TC74HC4020P||14-stage binary ripple counter — clock division / timing
+|-
+|'''M14, M15'''||Toshiba TC74HC132P (×2)||Quad 2-input NAND Schmitt trigger
+|-
+|'''M18, M22'''||Toshiba 74HC00AP (×2)||Quad 2-input NAND gate
+|-
+|'''M16'''||Toshiba 74HC08AP||Quad 2-input AND gate
+|-
+|'''M17'''||Toshiba 74HC14AP||Hex Schmitt-trigger inverter
+|-
+|'''M10'''||Seiko S-8054ALR||Voltage detector — power-on reset / low-voltage supervisor
+|-
+|'''M21'''||National Semiconductor LM358N||Dual op-amp — analog signal conditioning / comparator
+|-
+|'''M20'''||Maxim ICL7660CPA||Switched-capacitor voltage converter — generates the −5 V rail (TP3) from +5 V
+|-
+|'''M19'''||Toshiba TDG2002P (TD62002)||7-channel Darlington sink driver array — drives buzzer / indicators / low-current loads
+|}
+===Clock & Configuration===
+*'''X1''' — 4 MHz crystal (MC6809 ÷4 → 1 MHz E/Q bus clock), with C1/C2 loading trimmers
+*'''JMP1''' — 3-position configuration jumper
+*'''BAT1''' — lithium coin cell, backup for the TC5564 SRAM
+*'''M13''' — unpopulated 8-pin position
+===Connectors===
+{| class="wikitable"
+!Connector!!Function
+|-
+|'''J-1'''||+5 V power input to the board
+|-
+|'''J-2'''||Front-panel board ([[#OEM No. 126C|OEM No. 126C]]) — LCD display, LED readouts, keypad (40-pin ribbon)
+|-
+|'''J-3'''||HV control board ([[#OEM No. 127 (A/B) — HV Controller Board|OEM No. 127]]) — maps pin-for-pin to the 127 board's [[#J-16 Data, Status and Telemetry|J-16]]: DAC setpoint out, voltage/current PWM telemetry in, circuit open/shorted/unknown status
+|-
+|'''J-4, J-5'''||Small I/O harnesses (3-pin) — function TBD
+|}
+===Other===
+*'''BZ1''' — muRata piezo buzzer (audible alarm / key-click)
+*'''Q1–Q5''' transistors, '''D1–D13''' diodes — discrete interface / level shifting
+*Test points '''TP1–TP7''', '''+5 V''', '''−5 V''' (from ICL7660), '''GND'''
+*An unpopulated 20-pin DIP position sits between M3 and M11
+===Reverse-Engineering Notes===
+#The MC6809 + MC6821 + dual MC6840 set is a textbook Motorola control core. The two PTMs are well-suited to ''measuring'' the voltage-PWM and current-PWM the 127 board returns over J-3 (gate / capture), and to generating the volt-hour and timed-run intervals for the four operating modes.
+#J-3 is wired pin-for-pin to the 127 board's J-16, so the 125B PIA directly drives that interface: HV-enable, DAC clock / data / strobe out; circuit open / shorted / unknown status in. The keypad scan / display strobes go to the front panel on J-2.
+#The Signetics CK2605 FPGA (M7) handles glue logic — address decoding and control sequencing — alongside the discrete 74HC138 / HC00 / HC132 gates.
+#The S-8054 voltage detector (M10) provides power-on reset and brown-out supervision, gating the CPU and protecting the battery-backed SRAM during power transitions.
+#The ICL7660 makes a local −5 V rail for the analog / op-amp section rather than relying on the 127 board's ±15 V.
-==OEM No. 127A — HV Controller Board==
+===Items Still to Confirm===
-This is the analog/digital control board that bridges the front-panel microprocessor and the high-voltage power module. It accepts a digital setpoint from the μC, generates two PWM drive signals to control the HV switcher, and reports back the actual HV and HC values via a frequency-isolated telemetry path. It also handles fault detection and shutdown latching.
+*Identify the J-4 / J-5 harnesses
+*Dump the CK2605 (M7) configuration / determine its logic role
+*Determine J2 pinout to front panel board
+==OEM No. 127 (A/B) — HV Controller Board==
+This is the analog/digital control board that bridges the front-panel microprocessor and the high-voltage power module. It accepts a digital setpoint from the μC, generates two PWM drive signals to control the HV switcher, and reports back the actual HV and HC values via a frequency-isolated telemetry path. It also handles fault detection and shutdown latching.<gallery mode="slideshow">
+File:BIO-RAD OEM NO 127A Top.jpg|'''127A''' - Top of board, J-16 and optocouplers in bottom left
+File:BIO-RAD OEM NO 127A Bottom.jpg|'''127A''' - Bottom of board, cutout under optocouplers in top left for high voltage isolation
+File:BIO-RAD OEM NO 127B Top.jpg|'''127B''' - Top of board, J-16 and optocouplers in top right
+File:BIO-RAD OEM NO 127B Bottom.jpg|'''127B''' - Bottom of board, cutout under optocouplers in top left for high voltage isolation
+</gallery>
 ===Connector Map===
@@ Line 174: / Line 273: @@
 [[File:BIO-RAD OEM NO 127B Conn J16.jpg|none|thumb]]
 J-16 carries four data lines to an on-board [https://wiki.recessim.com/w/images/f/fc/AD7543.PDF AD7543] Digital to Analog Converter (DAC) which selects the voltage generated by the power supply. 0 - 4095 is the valid range to set ~20V to 3000V in 0.7V increments. It also has PWM outputs for voltage and current to monitor actual values and three additional I/O lines to signal Circuit Open, Circuit Shorted and one Circuit Unknown, possibly to signal a ground fault condition per the user manual. This connector goes straight to optocouplers so the control side is isolated from the high voltage side.
+====Pin Definitions====
 {| class="wikitable"
 |+J-16 Pinout
@@ Line 250: / Line 351: @@
 |}
+====Timing Information====
+<gallery widths="300" mode="slideshow">
+File:BIO-RAD 3000Xi DAC Data Capture.png
+File:BIO-RAD 3000Xi DAC Data Capture - Enable to Clock.png|HV Enable low to start of data
+File:BIO-RAD 3000Xi DAC Data Capture - Clock Timing.png|Clock signal timing
+File:BIO-RAD 3000Xi DAC Data Capture - Data Timing.png|Data signal timing, centered within clock
+File:BIO-RAD 3000Xi DAC Data Capture - Clock to Strobe.png|End of clock to strobe timing
+</gallery><br />
 ===Active Components===
@@ Line 313: / Line 422: @@
 {| class="wikitable"
-!Position!!Part Number!!Marking!!Output!!Datasheet
+!Position!!Part Number!!Output!!Datasheet
 |-
-|'''REG1'''||Fairchild '''μA79M15A''' (Korea)||"μA79M15A UC871x KOREA"||'''−15 V''' analog rail||[https://www.ti.com/lit/ds/symlink/lm7900.pdf 79xx PDF (TI)]
+|'''REG1'''||7805||'''+5V''' Digital Rail||[https://www.ti.com/lit/ds/symlink/lm340.pdf LM340 PDF (TI)]
 |-
-|'''REG2'''||Fairchild '''μA 78M15''' (Korea)||"μA 78M15 UC8704 KOREA"||'''+15 V''' analog rail||[https://www.ti.com/lit/ds/symlink/lm340.pdf 78xx PDF (TI)]
+|'''REG2'''||7815||'''+15 V''' analog rail||[https://www.ti.com/lit/ds/symlink/lm340.pdf 78xx PDF (TI)]
 |-
-|'''REG3''' ''(or REG4)''||National '''LM340T-12'''||"EM340T12 7812 P+" 8730||'''+12 V''' rail||[https://www.ti.com/lit/ds/symlink/lm340.pdf LM340 PDF (TI)]
+|'''REG3'''||7915||'''−15 V''' analog rail
+|[https://www.ti.com/lit/ds/symlink/lm79.pdf 79xx PDF (TI)]
 |-
-|'''REG4''' ''(or REG3)''||Fairchild '''μA 78M05''' (Korea)||"μA 78M05 UC8731 KOREA"||'''+5 V''' digital rail||[https://www.ti.com/lit/ds/symlink/lm340.pdf 78M PDF (TI)]
+|'''REG4'''||7812||'''+12 V''' rail||[https://www.ti.com/lit/ds/symlink/lm340.pdf 78M PDF (TI)]
 |}
-<div style="border-left:4px solid #f0ad4e; background:#fcf8e3; padding:0.5em 1em; margin:1em 0;">
-'''Note:''' REG3 vs REG4 silkscreen position needs confirmation against the TO-220 part numbers — only the REG1/REG2 silkscreen was clearly visible in image 3.
-</div>
 ===Passive Components===
@@ Line 371: / Line 477: @@
 ----
-==OEM No. 125B==
-''Module not yet examined. Photos and reverse-engineering pending.''
 ==OEM No. 126C==