Rhine UC7051R ceiling fan remote receiver reverse engineer

[bobdring]

Hi,
I'm in the process of repairing/reverse engineering this elderly remote receiver controller fitted into a ceiling fan marked as the 'Omega luxury remote model 5300'. I couldn't find anything similar on the web and so have started this thread to record my progress and as an aid to anyone contemplating something similar.

*** Safety *** The circuit ties active and +5V power supplies together and probing it poses a risk of electric shock and the potential to damage test equipment.

First a general description of the controller.

The circular receiver is a single sided phenolic PCB marked Rhine UC3051R . The component designators are often under the components and so they have been removed and resoldered to document them. Some components do not have any designators and so I have made them up. There are two Q5s and I have named one Q5A. The RF section is under a tinplate shield.


The main IC U2 is a RH7050 probably a custom part made by, or for, Rhine Electronic Co Taiwan. No data sheet or a supplier has been found.

The receiver decodes six remote functions
FAN/OFF
FOR/REV
LIGHT DIMMER
HI
MED
LOW

The fan motor has two windings (my names A & B) one of which (A) has a permanent series 1.75 uF 350VAC capacitor which I have designated C25. The other motor winding (B) can be reversed electrically by DPDT relay K1. These windings are connected to the mains supply using TRIACS Q3 Q5A and Q11. The motor speed selection is achieved by supplying the motor (both windings) with either full or reduced voltage. The reduction is performed with capacitive droppers C26A and/or C26B

It should be noted that the controller IC U2 will not function without the zero crossing signal (ZCS) on pin 18. This signal is a current limited 20ms square wave of about 6.4V amplitude (probably 5V plus the CMOS IC intrinsic diodes). Since the ZCS is derived from the mains supply it makes it difficult to work on the PCB safely. I rigged up a an external DC supply for the logic and an isolated AC mains supply for the rest of the circuit. A better approach would be to simulate the ZCS (555 timer?) and leave the mains disconnected until it is absolutely necessary. The PCB and motor wiring is short and so I made an extension cable to connect the PCB to the motor using Molex connectors and some seven core cable. The PCB is now on the bench and the fan motor sits on a milk crate under the bench.

For those of interest the original fault symptom was that the fan would only creep around. The fan is now working but i don't know what I did to fix it! I didn't realise at first that the ZCS signal was needed and I thought I had damaged the PCB as even the reverse relay wouldn't energise when the PCB was powered from only a DC supply. By the time I learned about the ZCS I had already removed and re-soldered many parts and also re-tuned the receiver and it was too late to diagnose the fix.

The serial data line to U2 from the RF section has lots of noise on it. I spent a lot of time trying to figure out why. Save yourself some effort and accept it, as it seems to be normal. The reason it was not working was the missing ZCS signal not the RF.

I have attached a couple of photos of a similar receiver much more to come.

[bobdring]

Here is the Bill of Materials

PCB marked RHINE UC7051R

PARTS list

misc
T1 2413-28T tranformer
K1 OMI-SS-212L DPDT relay
S1 4WAY DIP SWITCH
L1  2 TURN RF INDUCTOR ON BOBBIN (IN RF SECTION)
L2 10 TURN RF INDUCTOR ON SLUG (IN RF SECTION)

resistors
R1 220R 1/4W (IN RF SECTION)
R2 10K 1/4W (IN RF SECTION)
R3 1K0 1/4W (IN RF SECTION)                              
R4 10K 1/4W (IN RF SECTION)
R5 47R 1/4W (IN RF SECTION)
R6 3K3 1/4W (IN RF SECTION)
R7 470R 1/4W (IN RF SECTION)
R8 3K3 1/4W (IN RF SECTION)
R9 10K 1/4W (IN RF SECTION)
R10 4K7 1/4W (IN RF SECTION)
R11 10K 1/8W
R12 10K 1/8W
R13 1M0 1/8W
R14 15K 1/8W
R15 4K7 1/8W
R16 1M0 1/8W
R17 6K8 1/8W
R18 6K8 1/8W
R19 6K8 1/8W
R20 6K8 1/8W
R21 6K8 1/4W
R22 82K1/8W
R23 1M0 1/8W
R24 6K8 1/8W
R25 1M0 1/8W
R26 missing?
R27 160K 1/8W
R28 430R 1/4W
R29 150R 1/4W
R30 150R 1/4W
R31 470R 1/4W
R32 47R 1/4W
R33 3R3 1 W
R34 47R 1/8W
R35 100K 1/4W
R36 2M2 1/8W
R37 47R 1/2W
R38 47R  1/4W
R39 missing
R40  100K 1/4W
R41 3R3 1 W

capacitors
C1 101 CERAMIC (IN RF SECTION)
C2 101 CERAMIC (IN RF SECTION)
C3 2.2 CERAMIC (IN RF SECTION)
C4 2.7 NPO CERAMIC (IN RF SECTION)
C5 2.2 CERAMIC (IN RF SECTION)
C6 22 CERAMIC (IN RF SECTION)
C7 102 CERAMIC (IN RF SECTION)
C8 0.01UF POLY 100V
C9 10UF 25V ELECT
C10 10UF 25V ELECT
C11 105 TANT
C12 100UF 16V ELECTRO
C13 104 MONO BLUE
C14 104 CERAMIC
C15 1000UF 25V ELECTRO
C16 100UF 16V ELECTRO
C17 103 CERAMIC
C18 NOT FITTED LINKED OUT
C19 104 400V POLY
C20 473 400V POLY
C21 473 400V POLY
C22 100UF 16V ELECTRO
C23 561 CERAMIC
C24 103 CERAMIC
C25 1.75uF 400WVAC WIRED
C26A 1.75 uF 350WVAC
C26B 3.5uF 350WVAC

movs
ZNR1 SAS391KD07 MOV
ZNR2 SAS391KD07 MOV

semis
Q1 MPSH10 (IN RF SECTION)
Q2 MPSH10 (IN RF SECTION)
Q3 BTA08600C (ST)
Q4 BTA08600C (ST)
Q5 8050
Q5A T410 600T (ST)
TWO Q5's !
Q6 78L05
Q7 8050
Q8 8050
Q9 8050
Q10 8050
Q11 T410 600T (ST)

diodes
D1 1N4004
D2 1N4004
D3 1N4004
D4 1N4004
D5 1N4004
D6 1N4004
ZD1 NOT FITTED  (IN RF SECTION)

ICS
U1 LM324 dip14
U2 RH7050 dip20

connector
molex 9way

more to come

[bobdring]

I have attached photos of component side of PCB

some parts were removed before the photo and replaced later

more to come

[bobdring]

I have attached more photos of component side of PCB

some parts were removed before the photo and replaced later

more to come

[bobdring]

I have attached more photos of component side of PCB

some parts were removed before the photo and replaced later

more to come

[bobdring]

Have attached photos of the PCB solder side

more to come

[bobdring]

Have attached more photos of the PCB solder side

[bobdring]

Added Xray type photos to help track tracing

more to come

[bobdring]

Added Xray type photos to help track tracing

more to come

[bobdring]

serial codes used by the remote copied from my other topic

[bobdring]

First sheet of schematic main connector, power supply and FWD/REV relay

more to come

[bobdring]

Second sheet of schematic motor connections, REV/FWD switching and fan speed selection

[bobdring]

Third sheet of schematic lamp dimmer and zero crossing signal

[bobdring]

Fourth sheet  of schematic RF section

[bobdring]

Fifth sheet of schematic  analog signal to digital signal conditioning

[bobdring]

Sixth and final sheet of schematic RH7050 control IC and support components

[bobdring]

This is the last post on the project.

Documenting the signals on U2 the RH7050 IC.

The signal names are of course my own invention and so may be misleading.

pin 1,2 & 7 - 0V one or two of these might be unused address code bits set to zero. One is the IC 0V

pin 3,4,5 & 6 REMOTE ADDRESS CODE - An address setting  of '1' would be HLLL or switch off,on,on,on

pin 8 OSC & 9 OSC OUT - These pins are connected by R29 160K to set the internal oscillator to 100kHz as measured at pin 9

pin 10 DATA IN - This is the digital version of the serial data from the RF section. It is pulsed from 5V to ground. There is a lot of pulses on this pin even when the remote transmitter is silent.

pin 11 LOW FAN - This 0V signal changes to a 10us 5v positive pulse every 100us when fan LOW pressed. It stays pulsing until FAN OFF or another speed is selected

pin 12 MED FAN - This 0V signal changes to a 10us 5v positive pulse every 100us when fan MED pressed. It stays pulsing until FAN OFF or another speed is selected

pin 13 HI FAN - This 0V signal changes to a  10us 5v positive pulse every 100us when fan HI pressed. It stays pulsing until FAN OFF or another speed is selected

pin 14 NOT KNOWN - This is triangular wave of period 90ms with a low of 2V and a high of 3.5V the wave has a 40ms rise time 50ms and a fall time of. It is still present even without ZCS

pin 15 NOT KNOWN - This is a square wave of period 90ms with a low of 0V and a high of 5V. The signal is 50ms high and 40ms low V. It is still  still present even without ZCS

pin 16 FWD/REV- This is 0V after power on then toggles with FOR/REV between 5V and 0V needs ZCS to be functional

pin 17 5V

pin 18 ZERO CROSSING SIGNAL- The ZCS signal is a 20ms square wave having a low of -0.7V and a high ov 5.7V

pin 19 LIGHT DIMMER- This is a series of 10us pulses every 100us. The 5V pulses start 1.5ms (for a bright light) after ZCS edge and always end 8ms after the ZCS. Holding the DIM button causes the start time to change either dimming or brightening the light. A short press of DIM button selects between light off and the previous light intensity setting.

pin 20 POR RESET - This normally hi at 5V it rises slowly (300ms) to 5V after power applied. It is probably the IC reset signal

Probing the IC pins often causes it to hang up and so it may be necessary to power off for a while to get it working again. Don't forget the 5V rail is at mains active potential.

There, I'm finally out of the rabbit hole... will post if anything new develops

I hope that someone finds it useful.

Bob