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Late 964 and 993 units use external EPROM for program memory, as far as I remember did they grow out of the mask programmed memory size as soon as they introduced the more advanced OBD functions.
However, I have seen early 964 units with EPROMs as well, not all of them were internal memory versions. I guess they ordered the mask programmed CPU's after some time to be sure it was working OK. By the way, all were standard EPROM memory chips, not electrically erasable.
What part number is on that CCU? Is that a later 993 unit? I have (not just early production) 964 CCUs with socketed EPROMs. They are just a pain to remove, as you have to desolder some connections in order to split the two main boards.
I don't really know what CCU that board came from. I just had many bad cores that I grabbed one to take a picture of.
With regard to using an external memory (EPROM), for those that like to write their own CCU code the 80515 can
be easily setup to read an external memory.
No- but for those that are concerned their fully functional ccu needs a change- that is a way to make that change.
As far as failed ccu go- I've used that company for a convertible top controller and it worked well and they were great to deal with. So if i had a failed ccu, i might give them a shout.
I had wanted to cut the fans off back when i first got my car- but then quickly realized i needed air flow anyway. So i let that one go many years ago...
If it hasn't been noted- these guys sell a ccu that has been "upgraded" to not run the fans.
I personally don't think it's an upgrade. But if you want the fans off- swap for one of theirs and you have a new ccu and no fans.
This has been discussed several times here and in other forums.
One of the threads is here: https://rennlist.com/forums/993-foru...mendation.html
In my opinion, these guys are doing misleading and incorrect marketing.
T
Thanks to all for replying, these are the answers I was looking for: basically, this CCU ‘upgrade’ doesn’t seem worth it, even for an early 964 like mine. I would, however, appreciate some opinions on these errors my climate control is throwing:
I assume these mean I need to replace the little fan on the back of the CCU. My climate seems to work fine, but the temperature control doesn’t seem very sensitive. The mixing servos only seem to go full hot, full cold, and right in the middle. Thoughts?
And regarding the ECU repair place mentioned previously: I dealt with them when trying to figure out my varioram conversion and they were courteous, but they sold me a “993” ECU with a handwritten part number that couldn’t operate the varioram. Granted, I was doing something a bit off the beaten path.
06-04-2020, 12:18 PM
