Cruisin101

Spent the previous week reviewing the monster ecu thread and just received caps for my "93 from Digi-Key. I sourced out service locally but the tech couldn't figure out how to get the board out of the housing. The board with the caps is secured on one side somehow but even if it was loose the ribbons are keeping everything together.

RA40

iTrader: (6)

I can't recall if there was a terminal to disconnect. Rather than risk handling damage I left it and clamped it to the frame of the ECU housing.

PhilipMidd

Lots of screws all around the outside of the aluminium frame - Frame doubles as heat sink for lots of power transistors. They are mounted on the PCB and screwed into the sides of the frame. I'm pretty sure you need to remove ALL screws from the outside. On mine (earlier than yours) I had a spacer in the middle of the board, bolted both sides through both PCB's. Only need to remove one of them.but no harm if you do remove both.

Dont try and pull / twist / unsolder the ribbon(s). just gently open the boards up to 90 Degrees, or 180 if you have to. The ribbon will be old and may be brittle. Dont mess with them.
Hope that helps.

Htony

Just practice some anti-static measures handling board like this. Could be damaged in silence. Replacing caps. make sure of the polarity. If you install it backward by mistake, Kaput! it'll act like a dead short blowing
something.

Cruisin101

Thanks Guys, I lucked out finding a tech who did the repair with the board still in the case. Everything is back together and like most I've found the car more responsive and it feels like its gotten back some of the lost power. Only found one cap just barely leaking. The car was running great before the repair then in the last 500 miles the mpg has gone from just under 15 to 11.2 mpg.. Changed out the temp sensor a few months back but it didn't improve mileage. Hope this sudden drop in mpg is a result of degrading caps.

Htony

To really check the status of a capacitor, we use ESR meter. Simple multimeter method won't give guaranteed result. Caps. being same vintage there are good chance others will fail sooner or later. While at it it is desirable to replace them all. Simple ESR meter is very cheap nowadays. Another handy use of ESR is to check start/run cap. on air conditioning outdoor unit. Very common problem we have on start/run capacitor. This cap usually costs 20.00 or so, but a/c techs gouge customers charging for it like 200.00, LOL!

RA40

iTrader: (6)

Did they replace all the caps?

Cruisin101

All the caps were replaced as outlined in he master leaky caps thread.

PhilipMidd

Cool. Yeah, for the little extra cost (less than $10 in parts) its not worth only doing a few. Plus as the thread mentions, they dont have to be leaking to have failed.
I did mine a little while ago. None of mine were leaking, but I did them anyway when I got a reading way out of spec by measuring the ripple voltage from under the bonnet (Diagnostics Port). Mine was 70mV, Anything over 40mV can be considered a fail.
( https://www.clublexus.com/forums/ls-...-by-yamae.html )

dicer

When handling PCB's always wear a wrist strap ground, I have it going to the ground terminal on the wall plug. ESD is very nasty stuff and will fry a micro circuit very easily. Been there done that years ago.
PCB ----------------> Printed Circuit Board............... ESD ----------------> Electro Static Discharge (like when you walk on a carpet and get a shock)
That big static spark jumps a molecule size dimension very easy and cooks the molecule. That is the simple easy description of what happens.

spuds

You growing those tomtoes?