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disregard the tr7 question. I have brand new OE c144 in stock that I had made for repairing these boards. i dont usually sell the components separately but PM me and I can make an exception as it looks like you know what you are doing.
Also good news i just watched the video of your speedo, and tbh it looks fine you just have the needle placed wrong on the motor spindle. the way these motors work is they rotate 300 or so deg not the full 360. we rever to the stops prior to the dead space as hard stops. it has a hard stop on the low side of rotation and the high side. Your high side hard stop can be checked like this......use your finger to gently rotate the needle to say the 120mph mark on the speedo and then let the needle fall to that side on its own. where it stops rotation is called the hard stop...when it stops it should be pointing at the 6 in the text that says "60mph = 1024rpm" at the bottom right corner at the gauge applique. if it rotates clockwise past that and point then the procedure is as such.......use your finger to rotate the needle on the spindle counter clockwise and veeeeeery gently lift the needle over top of the physical plastic piece that would otherwise hold the needle at 0 and then continue to rotate the needle to pointing straight down. now you need to rotate the needle clockwise veeeeeeery gently lift the needle back over the physical plastic pin and then back to the 120mph mark and let it once again fall on its on clockwise until it stops at the hard stop. then the final step is use your finger to gently continue the rotation past the hard stop until it points to that affore mentioned 6 in the text that says "60mph = 1024rpm" at the bottom right corner at the gauge applique. the final step is to rotate the needle back counter clockwise and then let it fall on its own back to the plastic pin that holds it at 0. done! this needs to be done any time the needle moves on the motor spindle or is removed from the speedo altogether.
Replace zd3 with a 5.1 and what transistor did you use for tr7? Gain is important here. There's not an exact replacement with exact gain for the c144 and that doesnt look like a c144. Not saying that's the issue. Also I havnt seen a video of the tach floating. Describe what you mean by float. Is it jumpy?
thanks for suggesting replacing zd3. I've used NTE123AP for tr7, its much bigger in size than the original one. Actually tach is fine, its speedo that floats. I've two videos attached to post #292 - https://www.rx7club.com/3rd-generati.../#post12488907
thanks for suggesting replacing zd3. I've used NTE123AP for tr7, its much bigger in size than the original one. Actually tach is fine, its speedo that floats. I've two videos attached to post #292 - https://www.rx7club.com/3rd-generati.../#post12488907
yes. see my post above. I believe your speedo is actually fine. it looks like the needle is not placed correctly.
I noticed the speedo face and needle was removed from its motor. However, the motor was still soldered to the board. After seeing that, there is a possibility that the driven pin is damaged. This is common when some owners pull off the needle from the tach or speedo motor. To test, apply small pressure to rotate the needle. You should feel some resistance and the needle would not move from its new position. If the needle freely spins from stop to stop and it does not stay in a given position then the driven pin (or axle, or shaft) is damaged. If the pin is damaged then a new motor is required.
To my knowledge, the only replacement motor is cannibalized from another speedometer.
Did you follow zensation's recommendation to place the needle back on the speedometer motor? I just read it after making my observation, sorry zensation!. Please follow zensation's recommendations first. And pay heed to his warning - be VERY gently when inserting or rotating the needle to avoid damage to the driven pin.
Did you replace C4 and C6 too? From the angles of the photo, those 2 caps look original to the board. If you haven't changed them already, then please consider replacing them to stay ahead of leaking electrolytes.
Could you take a closer photo at TR3 and D2? Their solder joints don't look right. It maybe shadows or orientation of the card, but I would like to verify they are good. Speaking of solder joints, I noted a few large globs on some replacement caps. A good solder joint should look very similar on both sides of the through-hole. A small mountain peak with a flag running in the center.
In my former line of work we had a saying when joking around the solder station, "the bigger the blob, the better the job." This is a misaligned axiom which does not guarantee a good mechanical connection or good electrical connection. You can use several solder joints that surround the discrepant component to gauge the right amount of solder on either side of a through-hole joint.
Please continue to post your results on this repair!
Hi all this is a great tread - hope someone can assist with my speedo board issue.
I sent my speedo to a guy for repair and he told me he done the following; traces on c3, replaced the caps. Changed the crystal, diode array, eeprom, & zener diodes near c3. ......The repair was unsussesful and I sent it to Michael gagne who repaired and bench tested ....all back working along with picking up few issues with previous failed repair.
I then installed and noticed my buzzer would go off when under load i.e driving and not under idle.
after chasing my tail on coolant buzzer etc...I got a loan of a cluster / board off a local shop and the isolated the issue to my repaired speedo board.
My speedo and rev counter are working but something funny is going on which sets my buzzer off as soon as I start driving.
can anyone point me in a direction on the board to inspect and also could it be something to do with the rev limit is out of wack and setting off the rev limiter buzzer under miss information / calibration.
It sounds like your Overrev buzzer is going off. What EEPROM was replaced - was it IC5 (the big square IC)? Could you post a closer pic of IC5 from the last photo?
It looks like your board absorbed a lot of heat from all the solder work it received. I am surprised to hear the crystal was replaced. The crystal establishes a clock freq to synchronize all the speedo functions. Does the replacement crystal match the frequency of the original? How accurate is your speedo?
It sounds like your Overrev buzzer is going off. What EEPROM was replaced - was it IC5 (the big square IC)? Could you post a closer pic of IC5 from the last photo?
It looks like your board absorbed a lot of heat from all the solder work it received. I am surprised to hear the crystal was replaced. The crystal establishes a clock freq to synchronize all the speedo functions. Does the replacement crystal match the frequency of the original? How accurate is your speedo?
Thanks for your message, yes the large eeprom was replaced - I will grab a close pic of it when I get home.
The speedo seems slow to get going...... have not done a proper test on it.... buzzer 2 much of headache but I will on Saturday...
I will also grab a pic of the crystal this evening
the coolant light is on very faint & only notice it when I drive into garage. Do you know if the oil, coolant, over rev buzzer are all on the one circuit?? And will signal the faint coolant light?
all issues go away when I change out the cluster/ speedo board so def the speedo board.
It sounds like your Overrev buzzer is going off. What EEPROM was replaced - was it IC5 (the big square IC)? Could you post a closer pic of IC5 from the last photo?
It looks like your board absorbed a lot of heat from all the solder work it received. I am surprised to hear the crystal was replaced. The crystal establishes a clock freq to synchronize all the speedo functions. Does the replacement crystal match the frequency of the original? How accurate is your speedo?
The buzzer is part of the warning circuit for Coolant, Overrev, and Seat Belt.
Please take closer shots of this IC (IC5). I want to see the condition of the legs on 3 sides, especially where you see that brown goo. I am checking for proper contact between the legs of that IC and the solder pads. Zoom in on the legs of IC5.
I moved your posts into this thread because it deals more with troubleshooting the circuit board. The other thread deals with identifying components for replacements.
The buzzer is part of the warning circuit for Coolant, Overrev, and Seat Belt.
Please take closer shots of this IC (IC5). I want to see the condition of the legs on 3 sides, especially where you see that brown goo. I am checking for proper contact between the legs of that IC and the solder pads. Zoom in on the legs of IC5.
Do you know if the overrev coolant and seatbelt are a linked / grouped eg if there is an overrev issue will it also set off the coolant faint light.
Thanks for all you help. Also I can't seem to see a code or info on the crystal to determine if its the correct replacement assume it should be....
The buzzer receives an input from multiple sources so it is unlikely to cause any feedback issues. If a known good speedo fixes al the problems then the problem resides with this damaged speedo board.
I am concerned that IC5 has some warped pins. The area where you see the brown stains is the area of concern.Was that IC replaced with a new unit or was it cannibalized from another speedo?
Given the extent of the damage to this circuit board, you may be better off with a new replacement. I don't want to abandon hope just yet because you obviously spent some money fixing it. There could be other areas on this board that need attention.
Please get a close up of those IC5 legs near that brown stain (dried flux). I mean get in there! I want to see those legs.
Dec 11, 2021- hey, don't know where I should jump in here since I have been out of this conversation for so long. Car is put away or at least in the garage on a lift for a few repairs this winter. Last season was a bust as business was/is crazy and I made 2 track events all year: oh well. So when I last wrote in the tach was working and then it wasn't along with the gas gauge which wasn't working. I packed it up today to send back out to zensation for a check over. But, now that I have everything torn down again I want to remove and repair that wire pin 3F that Gen2n3 helped me determine could be the problem. I thought I repaired it, however, I would just like to make sure. Does anyone know how to remove those pins? are you able to send a photo of the tool or tell me where to go and how to do? I would be most appreciative of that info. Once removed and replaced, how do you check its viability of connection? Thanks, JD.
Welcome back! To remove the pin from the connector you will need a pin extraction tool. I haven't used one yet, but this generic tool may be used to remove the pin without damaging the wire, pin, or connector backshell.
As a reminder, I do not own this particular tool nor have a similar tool to extract pins. If you are looking to test that wire then you will need a DMM and the wire schematic. Did you disconnect the screw-on wires to your tachometer after repairing the wire splice & cut? Do you remember how to check for continuity in a wire?
As always, post photos and I'll do my best to help.
Hi guys I’m having issues with my jdm 1993 rx7 fd not displaying mileage. I bought a replacement speedometer that was known working and looks to have been repaired in the past. I fitted this and have the same issue of no mileage being displayed.
ive been told that if I put 12v to “ILL” and ground the “PGND” it should show the mileage on the odo however it isn’t. Have I been told correctly about the testing procedure or am I missing something?
aswell as the above, are there any common problems? Power feed to the cluster or grounding issues that could cause this?
Engine has recently been out and have made sure that the earth on the firewall is secured and cleaned up correctly.
Hi guys I’m having issues with my jdm 1993 rx7 fd not displaying mileage. I bought a replacement speedometer that was known working and looks to have been repaired in the past. I fitted this and have the same issue of no mileage being displayed.
ive been told that if I put 12v to “ILL” and ground the “PGND” it should show the mileage on the odo however it isn’t. Have I been told correctly about the testing procedure or am I missing something?
aswell as the above, are there any common problems? Power feed to the cluster or grounding issues that could cause this?
Engine has recently been out and have made sure that the earth on the firewall is secured and cleaned up correctly.
any help would be greatly appreciated
Welcome to the club. Far as I know, Lack of Odometer Display is usually caused by a few failing capacitors. With the age of these cars, it is certainly possible that both clusters are experiencing the same or similar issues. There is a fellow on FB by the name of Michael Gagne whom is exceptionally well-versed with FD cluster repairs, and would be the person whom I would ask this question to. Unfortunately, he is currently taking a break from cluster repairs as of recent due to personal matters.
From what I understand, waking the entire cluster is needed for a bench test in the manner you are trying to do. I've done so before with a FC Cluster using a spare subharness and bench power supply, giving it power and ground to their respective pins to mimic the Ignition Switch being ON. Buzzer came on after a second or two, until the Coolant Level sensor (not sure, this is from memory from 2013ish) pin was grounded too. (simulates sensor saying "we're good here". Fairly sure FD clusters would behave similarly, so consult the FD wiring diagrams for the correct information before starting on it. Also, please be aware that Japanese FDs may have their connectors pinned slightly differently due to region-specific matters such as the Check Engine Light we received in North America.
Since there are 6 different Wiring Diagram books for Japan, a VIN number would greatly narrow it down so I can help you with the correct information. Let's get it right the first time and not make things worse by guessing.
Please do NOT connect 12V to Illum and a ground wire to PGND on the speedo board. If you tried a known good speedo in your cluster and it doesn't work there could be 2 things wrong: The replacement speedo, which was previously repaired, may have failed. Or there is another issue with your instrument cluster.
A common mistake when connecting the speedo is user error: Did you connect the flat ribbon cable to the speedo connector? That will also cause no display. Additionally, make sure the ribbon cable tabs on the instrument cluster are clean and are curled out towards the hard shell connectors. The ribbon cable tabs are interference fit with the connector so they make contact. Do NOT crease those tabs - curl them outwards.
Do a search for my username and FD Speedo. There will be a wealth of information covering this topic.I also have a similar topic on the Instrument Cluster.
Sorry to hijack this thread, but I've also been trying to fix my odometer as of late. It suddenly failed to turn on two weeks ago, and initially I was able to fix it by replacing the 1000 uF capacitor with one that I happened to already have. The replacement I used was a 10V, despite the original being a 6.3V. When I tested it afterward by plugging in the cluster and turning my ignition to "on," the odometer worked and displayed the correct mileage. A week went by, since my cluster hood had broken in multiple places during removal, and I had to wait for the new one to arrive. Once I had that reassembled and reinstalled, I tested the odometer again- nothing. I've since replaced the two 10uF, 50V caps, and inspected my speedo ribbon cable, but still no dice. Any ideas?
Sorry to hijack this thread, but I've also been trying to fix my odometer as of late. It suddenly failed to turn on two weeks ago, and initially I was able to fix it by replacing the 1000 uF capacitor with one that I happened to already have. The replacement I used was a 10V, despite the original being a 6.3V. When I tested it afterward by plugging in the cluster and turning my ignition to "on," the odometer worked and displayed the correct mileage. A week went by, since my cluster hood had broken in multiple places during removal, and I had to wait for the new one to arrive. Once I had that reassembled and reinstalled, I tested the odometer again- nothing. I've since replaced the two 10uF, 50V caps, and inspected my speedo ribbon cable, but still no dice. Any ideas?
@Mr357, follow the same advice I offered the OP. Search for my username and FD speedo troubleshooting. You will need to re-inspect your speedo for other probable faults. I recommend replacing the capacitors with the original values. They are easy to find on Mouser or Digikey so no need to improvise on component values.
Thankyou. What is the correct way to test the odo outside of the car?
ive replaced the capacitors on my original speedometer but no luck with it working unfortunately.
If I could either confirm the speedometer working or not with the correct test procedure I’d be able to know wether it’s either my car or the speedometer it’s self causing the problem.
You are welcome. Sorry to hear that you are having a hard time with your speedometer. There is no easy way to test the odometer outside of the car. You would need to connect the instrument cluster into the instrument panel harness. This can be done without attaching the cluster to the hood. It can rest between the steering column and instrument cluster void. You also do not need to start the car or take it for a drive to verify the odometer. The odo will be visible after the ignition switch is placed to the ON position (engine not running). At this point, you only check if the odometer is visible.
I doubt the problem is with your car because the problem went away after you tested a known good speedometer. Therefore, the problem is within your speedometer. Fixing a speedometer is no easy task, depending on how long the odo was blank. There could be other damage to the speedo board that others may not have noticed.
If you post some photos of the speedo board then I may be able to help. Use the zoom function or get in close to take pictures of the suspect areas on the board. I also need you to provide more information: what specific components did you replace? Did you replace them or did a solder technician do it? Do you have any prior experience behind a soldering iron?
10-15-21, 10:16 AM
