Sick as a dog and then suddenly all good

[Red_Bullet]

Yeah, the ooze at he base of the capacitors was quite visible. I used to work in the elevator industry and I'm very aware that electrolytic capacitors can cause all kinds of grief. There was a period where capacitors were being manufactured in China from stolen Intellectual property, trouble is they stole the wrong recipe which led to the manufacture of billions of capacitors that were faulty. Consequently many electronic items had life shortened by that fiasco. The electrolyte in capacitors tends to dry out over time also, causing failure. I've fixed many a circuit board at work by replacing capacitors. Always use capacitors rated for 105 degrees, not the cheap 85 degree rated ones.

[manga_blue]

Thanks RB. I just cleaned this board again and all components still look good. The main concern is that a lot of the solder joints are beginning to look a bit oxidised. Nevertheless the board is working again. I'm beginning to wonder how long they typically last though. It amazes me that it's 25 years old.

IMG_20200403_124904536.jpg

[Red_Bullet]

Yeah, electronics are pretty reliable, Many elevators still running 30-40 years on. Generally, if it lasts the first few weeks then it's good for a long time, electrolytic capacitors aside. I still have hi-fi amps in that sort of age range too, which still work fine. Heat is the enemy of capacitors too, so if you are getting a lot of heat into the ECU from the exhaust downpipe then that could eventually be problematic.

(edit) if it continues to have intermittent issues then if you are willing to ship it up to me Brisbane I can change the capacitors for you and have a look over it for anything obvious. Cost, just parts and shipping.

[manga_blue]

Thanks very much for the offer, RB. I've relocated another ECU that I socketted about 12 years ago and it's been stored in a dry climate for most of that time. It should turn up in a few days. So hopefully I'll be right.

Off topic. Back in about 2000 I ripped all the capacitors out of a PC motherboard and replaced them all with better spec ones. The kids thought I was mad but it worked.

The fun part here is that I've scratched around the house, found the old EPROM burner, a UV light, a laptop with a serial port, a handful of EPROMs and all the cables. I needed that because I left the ROM init out in the sun to dry and that erased it. So I've burnt some new ROMs with the most aggressive fuel and timing maps I had and clipped one of them in. The car's going like a stung cat. It can't last though.

[Red_Bullet]

Yup, so you are handy with a soldering iron. Very good. Not everybody has an eprom burner either. I wonder if it was that zero insertion force eprom socket giving you grief, high resistance on a pin. I used to find when burning eproms that you would sometimes need to wiggle the eprom about in the socket to get it to work.

[manga_blue]

Yes well the ZIF is now coming under suspicion. When the other ECU arrives I'm tempted to desolder this ZIF and hard solder an EPROM back in there.

A little bit more investigation shows the timing mark skipping about a little under the timing light. Wondering if this means the CAS is getting suss too.

[Red_Bullet]

Maybe clean up the ZIF socket with some electronic cleaner and compressed air, or if that fails just stick it in a push in socket. It'd be good to keep it swappable.

With the timing varying it sounds like it's time for an oscilliscope on the CAS signal. What fun!! (I really don't miss working at all.) However I guess it's giving you something to do while in lock down.

[Maverick]

Nine times out of ten it’s the CAS creating your problems...


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[manga_blue]

I think it's a bit of both. I've got the ECU sorted, now I'll get a rebuild kit for the CAS.