Forums/Z31P/z31-repairs-forums electronics/Digital Dash Controller / Power Supply replacement effort
Imported from Z31Performance.com Forums{{#if:Acmex| — original post by Acmex}}{{#if:2021-04-20 20:48:05|, posted 2021-04-20 20:48:05}}{{#if:23| · 23 post{{#ifeq:23|1||s}}}}{{#if:/Z31performance_archive/forum/z31-repairs-forums/electronics/545929-digital-dash-controller-power-supply-replacement-effort.html|
Local archive: view archived thread on dev.z31library.com}}
Acmex: (2021-04-20 20:48:05)
Greetings all,
As a part of my continuing effort to make my own life more difficult, I've spent the past few months reverse engineering the (early) digital cluster and it's power supply.
You may have seen the previous links to Reddit. Now, Reddit is particularly bad about storing information (only two sites are worse, I think) so this thread will serve as a continuing documentation of my progress, while my Github will document the finished product at each stage when I'm satisfied with the result.
As mentioned on reddit, I received the finished PCBs last weekend and then spent some time assembling them. I also received a few more filament driver demo boards, which will allow me to power and test integration with all the VFD packages (there are five) before designing the actual replacement power supply.
About the filament driver demo boards:Each one has a linear regulator and a TI push-pull driver driving a center-tapped transformer. A negative "bias" voltage is supplied at the center tap, and the result is ~2V AC heating voltage set at -18.5VDC compared to the grids and anodes. A trim pot allows the output to be precisely tuned. The demo boards are actually grossly oversized due to an oversight early on. I anticipated between 800mA and 1600mA filament current (depending on the package) based on supply voltage and cold resistance. However, the filaments have a very strong positive temperature coefficient. Thus, actual current is ~100mA. As such, several components aren't needed, and the push-pull transformer can (probably) be downsized to a less expensive part than the $6 Wuerth one I had selected. About the compute module:Teensy 3.5/3.6 Level-shifting bus drivers translate the 3.3V to the 5V logic expected by the display's HV shift registers Parallel-in serial-out shift registers take in the 4 buttons on the front of the cluster, and the discrete inputs from the car Separate ADC reads in the 7 analog signals from the car:Supply voltage Fuel Level 1 Fuel Level 2 Oil Pressure Water Temperature Manifold Pressure Illumination Brightness (Bonus! Power supply board temperature [planned])
Protected inputs for the 3 frequency signals from the car:Tachometer Speedometer Fuel Injection Pulse Width
CANbus transciever available SPI EEPROM/flash available for storing misc data, including replacing the odometer with a small display. Supply voltages broken up in such a way that should allow powering off everything except the uC itself, which can then enter sleep mode. Warning light pass through, or replacement with Neopixels Currently I'm working on the proof-of-life code for the compute module, which is to demonstrate successful communication with all 11 display shift registers, as well as the illumination and odometer display. From there I will progress to actually processing inputs and updating the display in a timely manner. Then comes in-car intregration, and thus dash removal. Again. Hopefully I'll have an indoor work space by that time; it's soon to be hot and muggy down here. I don't have a timeline for any of this. Eventually, yes, they will be available to the public. Not until they're good and damn ready, though.
Ultimately, this is part of my much larger effort to develop replacements for most of the electronics in the car. As they come up they'll also be documented in the same way. Currently in queue are:Time Control Unit Center Gauge Pod Fuel Level Conversion Unit (being developed as a General Module; I'll probably use two or three of them throughout the car) My lock-up control unit has already been gutted and turned into a fan controller. As everyone knows, it's best to have things spread out as far a possible from their controlled load. That makes it more interesting. That's why I also have a RasPi car computer living in that same quarter panel for AA, monitoring, and diagnostics. I also intend to either use either a Nistune'd M30 ECU, or go standalone when the turbo goes in.
waynedwops42: (2021-04-21 21:33:18)
Impressive work, I don't understand 90% of what you said, but I do want to ask, any thoughts on completely bypassing the converter for the digital fuel sender unit and allowing for the analog fuel level sender to be compatible with the digital dash? Is it possible?
Acmex: (2021-04-22 02:27:32)
That will be possible, and is actually what I intend to do for personal use.
Note the four empty footprints under the grey connector -- these are the resistors at the top of the voltage dividers for the passive analog sensors (water temperature, oil pressure, 2x fuel level). Conventional wisdom holds that they should be equal to the value of the sensor at it's measurement midpoint (for linear curves). I elected to make these through-hole components for ease of substitution, though they do also need the higher power handling ability I think.
kaur: (2021-04-22 14:07:43)
At that point it also shouldn't be hard to use a different fuel level sender, maybe something more generic. Never know how long the stocks last for the OEM ones.
Acmex: (2021-04-22 19:19:58)
Yup -- Z_Karma tabulated tank capacity vs fluid height for me, which means the only action required to retrofit a completely different sender is to mechanically adapt it.
The same goes for all the other sensors such as GM MAP, Honeywell Oil Pressure, speed pickup, etc. The stock temperature thermistors are probably OK, but are also eligible for replacement. Just a matter of mechanically adapting (and providing the sensor supply & ground for active gauges).
badq45t: (2021-05-04 21:27:40)
here a workaround for the sending unit, this works generic
https://www.ebay.com/itm/14370981704…cad031gm700004
Acmex: (2021-06-30 22:03:07)
Sorry for the radio silence. Got myself stuck into some other projects & maintenance.
I have the power supply & data interface working for the "core 4" VFD panels. The trip meter panel, however, keeps exploding the diode used bias the filament. Even two months on I haven't found the short that *has* to be there somewhere.
Additionally, my testing arrangement for the power supply isn't robust enough to survive going in the actual car. Too little headroom for the knockoff buck converters. Throwing together a "production" supply with real components is, unfortunately, a no-go at the moment due to the ongoing supply problems. Shoot, I can't even build a duplicate control board at the moment because I can't get any additional Teensys for the right price.
Someday it'll work out.
Acmex: (2021-09-16 04:02:18)
Due to exceptionally heavy rains last week, my basement flooded to a depth of 4.5'. This destroyed all my spinning disks and the power supplies in my server(s). The working copies of the PCB design, as well some of my notes, were stored one of those servers. Data recovery is prohibitively expensive for the spinning rust, but I'm holding out some hope that the solid states in my old desktop have previous versions that are still intact. Technically I can still reorder from OSH, but I don't think I can pull the kicad_pcb files back from them.
This has been a brutal reminder that any backup of data stored in the same location is not a backup at all. I should have been pushing to Github, but was instead only committing to the local copy of the repository and saving to a network location.
Z_Karma: (2021-09-16 16:40:51)
Oh shit man, that's fucking brutal. Best of luck in your recovery efforts, not just the project files but the flooding damage in general.
For my home/work projects i started to share the files on Google Drive across 3 accounts, not so much for redundancy but storage limits.
badq45t: (2021-10-15 21:00:54)
Holy cow didn't see your post! I keep everything in OneDrive or Google Drive now, nothing really local for me anymore.
Acmex: (2022-03-16 02:21:34)
Recovered 90% of the design work from the solid states in my old server, which actually still works. Power supply and all. What I did lose was my demo code, which I get to write from scratch instead of just debugging whatever was wrong with the old code.
The chip shortage remains a PITA. The transformer drivers I selected for the prototype have no interchange and currently cannot be found anywhere. Boo. I'm looking at other options, such as the LM4871 (LM9022) or a fleet of FETs + microcontroller to drive them, but every option has it's pros & cons. The only con to the original plan is cost, at ~$12 / VFD channel driven. (Z31 dashes have 5 VFDs. Ouch).
In the meantime, have some teasers of how my other related projects are going. This time they're designed with parts I can currently get!Digital Dash Power Supply Time Control Unit (or BCM in modern parlance), featuring CAN and a couple additional outputs. Steering Wheel Controls adapter, featuring CAN & resistive output (theoretically). A fan controller built into the casing of an old transmission control module. Highly specific to my application (Manual swap, E-Fan w/ Mercedes PWM controller, additional pressure sensors, CAN parameter reporting to head unit). HVAC controller replacement designed around the cheap Mega2560Pro modules. Featuring CAN, OneWire, and 3 or 4 modern displays (IPS, OLED) to fit the space occupied by the original LCD. Digital Dash LED-based warning lights module to go with my controller.
Acmex: (2022-03-25 05:03:04)
Boards submitted to China for production. Bit of a shame, but western PCB production is simply too expensive for the likes of the HVAC main board. Would have been $100+ for that board alone, whereas with JLC I can get all the boards in the batch for $60 (30 + 30 express shipping).
In this batch:HVAC Controller SWC Adapter Consult<->CAN Bridge ECU Breakout My fan controller thing
Acmex: (2022-03-27 16:43:44)
18 months ago I demonstrated an arduino nano talking to individual VFD panels. Today I finally got back to that point, with the new controller and all four panels.
I also bought some color filters. I cut in a red one, hoping to get a nice amber like the clock. Sadly, the result was pink. It turns out the color spectrum is difficult. I may reach out to an actual VFD manufacturer and see if they can supply optimized filters.
Z_Karma: (2022-03-28 16:29:33)
When I was playing around with coloring my VFD, I bought a small Roscolux Swatchbook from a local stage lighting supply. Gel filters used for oldschool par-cans are heat and shrink resistant.
You can stack filters for custom colors as well.
Acmex: (2022-04-06 21:45:28)
Boards arrived after bouncing all over SEA for a week. Nailed the HVAC board dimensions, very pleased.
We shall see how pleased I remain.
Acmex: (2022-04-13 04:36:09)
For those who are interested in such things, so most of the wire-to-board PCB headers in the car are from a well-supported TE/AMP part line.
The handful of exceptions:The 15-position connector on the ECU. It's marked SJD, which should be Mitsubishi Wire & Cable (sold to Furukawa in 2011). The 22-position connector for the transmission control unit. No markings, but accepts the two 58S-type connectors. Compass amplifier, which is probably from the same line as the transmission control unit. The bulk of the "small" connectors on the car (see the black connector on my new HVAC board) are AMP DLI (Dual-In-Line) connectors. Found on the HVAC control heads, the dash power supply, Time Control Unit, ASCD, electronic suspension controller, JDM ABS controller. (Am I missing any?) You can find them on Digikey, Mouser, etc. with the "DLI" keyword.
Other points are the Jetronic-type injection connectors, which are from an unknown supplier initially. Later cars (M30, Z32) and the Z31 injector campaign harness connectors are Mitsubishi Wire & Cable (now Furukawa) Jet-Fire Control (JFC) (what a name!). I hate these. The retention clips are stupid and frustrating, and the plastic likes to crumble. Sadly Nissan used a bunch of strange key-ings that aren't in the common AMP lineup.
Small interior unsealed connectors are 58S. Large interior unsealed connectors are 58M, as are the relay contacts. Exterior sealed connectors are 58W. Corsa-Technic can supply the terminals & seals for these.
Z_Karma: (2022-04-13 15:18:12)
With all these different terminals and their corresponding expensive crimping tools, what are you using for crimpers?
One of the handiest tools I've found that is the closest to a universal terminal crimp tool is Molex PN 63811-1000.
It has crimp recesses that can be used on the wire and strain relief portions of all but the tiniest terminals I've encountered.
I've used them on JST/Molex/Hirose/AMP etc..and generic ring terminals with great success when i was our in-house cable guy.
It's not as easy as having the right tool, but then it's not 700.00 either.
Acmex: (2022-04-13 22:03:23)
That's the one I'm using for the 0.110" and 0.250" terminals on the car already. I haven't procured the DLI terminals yet. I also have a set of PA-09 crimpers for the Mini-50 and JST-XH terminals on my own designs. Sometimes I'll give the 0.250" terminals a tiny daub of solder if I've been forced into using the wrong size terminal, or if I expect significant current. Modern wisdom says not to, but Nissan clearly evaluated & approved the technique on our cars & through the 90s.
Acmex: (2022-05-12 04:20:17)
Because I can't stay focused on one project for more than 30 seconds, and require instant gratification, I've replaced the guts of the clock. Shame to lose that little VFD, but the HCMS 8-character LED displays fit the viewable window perfectly, are an excellent color match (well the orange one is, at least), and give more than twice the usable characters. The microcontroller has a proper RTC with battery backup, so I don't have to keep setting the clock each time I disconnect the battery to work on something.
At the moment it's really just a display & button board with a cable running out the back to the microcontroller, which wouldn't fit, but I'll have the proper board in the next PCB order.
This little guy will chat to the rest of the car over CAN, and let me view the wideband output & status, my fan controller state, and some Consult real time data when I get that box working properly.
I have also given myself the unenviable task of writing HVAC control logic. I might stick with the basic ePaper display for a while before I continue developing a full on replacement display board. I like the effect of displaying a constant logo, even when the board is hard-off.
Acmex: (2022-07-16 22:05:18)
The junkyard thoughtfully provided a fresh, good condition stock power supply unit. Cleaning of the contacts & fresh solder on the connector joints and it's working nicely. I'm going to avoid blowing this one up until I've completed comparative evaluation of my new design. I also got a digital dash speedometer cable, which is an oddly rare item.
The junkyard also provided a voice warning module. Not really of any use to me, but I thought I would at least dump the EEPROM, as the Z31 warning voice is actually synthesized instead of encoded on a record like all the other Nissan versions.
The revised HVAC module has been in and out of the car several times while I work on the mixing door tuning. It does run the system in a primitive manner without exploding, but cycles the adjustment solenoids far too frequently. I may abandon temperature control for now, and let the "Set Temp" buttons directly control the mix door position as on the manual climate controls while I just drive the car and log data off the new unit.
Finally, to get a good amber out of the VFD you have to stack two of the common "red" parcan filters from amazon. I figured I would try that before resorting to more exotic swatchbooks, but the result of two reds is just lovely.
Z_Karma: (2022-07-19 00:48:42)
You don't happen to have reverse engineered a pinout for either the analog or digital climate controllers have you? I've acquired several of each over the years and being able to bench test them would be superb.
Acmex: (2022-07-19 19:23:42)
Only in two places, my scribbled notes and the actual board design files on github. I gave up on the manual HVAC control head after realizing the pinout didn't remotely match the automatic one and I would have to swap that harness anyway. I would also like to know more about the stock display panel, but the stock LCD control IC also handles all the user interface & buttons and I'm not sure how to probe the LCD supply voltages. I think it's a static drive scheme, since they need 3 LCD controllers for this relatively simple display.
Power & ground are fed in on the 5-pin connector, VA & LA are switched power for ignition / accessory or lighting / accessory, respectively. VB is battery power. Supplying these should get you a living HVAC head (although no backlight).
+5V is the supply out to the thermistors/potentiometers/switches. The GND on the 40-pin connector block is the signal return for the same.
TA - Ambient temperature
DL - Lower Duct Temperature
DU - Upper Duct Temperature
DD - Defrost Duct Temperature
PL - Position of lower Air Mix Door
PU - Position of upper Air Mix Door
CANH/CANL/OneWire are me repurposing unused pins, or the stock "diagnostic" switch pins. Stock, CANL/OneWire trigger the input or ouptut diag mode CANH is unpopulated IIRC.
LC - Bulb Check Relay (Engine running signal, switched to GND if alternator not energized)
ZC - Sunload photodiode
TW - Coolant temperature switch
TL - Lower Interior Temperature
TU - Upper Interior Temperature
L1/L2 - Illumination bulb supply
GA - Superheat Timer ("Low Refrigerant Gas light")
SL - Lighting signal (Causes the LEDs to dim)
The outputs are all NPN transistors with zener diodes for suppression, except maybe the fan control voltage. I give the fan control voltage a +5V pullup and then PWM it to ground, which the digital fan amplifier is happy with.
VF - Fan output voltage
FR - Fan relay, low side switch
FS - Air Mix door 2 position control
F3 - Air Mix door 2 position control
VS - Air Mix door 1 position control
V3 - Air Mix door 1 position control
EM - emergency defog/defrost relay (full fan speed, full heat, AC ON, only for cars thru '87-ish)
Aux3 - Not assigned stock
Aux2 - Not assigned stock
V2 - Vent door solenoid
I1 - Intake solenoid 1
I2 - Intake solenoid 2
FL - Floor door solenoid
CR - AC compressor relay
Aux1 - Not assigned stock
Acmex: (2022-08-11 02:26:57)
Fully stock cluster is in the car and working well, after repairs. Some reaction basically ate all the copper by the VFD negative high voltage regulation pass transistors, and the regulating Zener for the trip meter was cracked in half. Anyone with digital cluster issues that aren't solved by touching up the connector joints should check these if the negative voltage offset is not present at the VFD filament drives. It all visually looked OK, until I poked the SMD resistors and they fell off the board.
I rather like the early (84 / 85-86) digital clusters with the triple bar displays better than the late clusters with the stupid "status check' box that they held over from the 280ZX. So now I have an '85 GLL cluster in my '88 GL. This required hybrid-izing the dash harness, although only three actual splices were required. This was due to differences in hazard warning, headlight retraction control, and fog light status, so I used the '88 switch pods and the '85 gauge wiring. It's also fun to watch the acceleration gauge do it's thing. I don't have a good compass controller so that gauge just sits idle.
I also swapped the new HVAC controller over to pure mix door position while I think about the algorithm a bit more. Works OK with just automatic air flow control, since GA demands I leave it at full cold for at least the next three months.