2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.
Sponsored by:

Please look at your CPU for me

Thread Tools
 
Search this Thread
 
Old 11-26-03, 01:10 AM
  #1  
cxr
Junior Member

Thread Starter
 
Join Date: Apr 2003
Location: North Carolina
Posts: 6
Likes: 0
Received 0 Likes on 0 Posts
Please look at your CPU for me

I've got a '90 vert and the cpu has gradually started to
fail. Looking at it, I see a resistor which supplies power to the unit has failed - probably slowly, so the rest of the unit is probably good. But in failing, it burnt off all the colors which would allow me to replace it.

If someone has a cpu they can look at, the resistor is one of two that stick up from (instead of laying along)
the board. It's about .5" below the relay and just to the left of an electrolytic capacitor. It's marked 'R1' on the board.

If you could read the colors/resistance from your unburnt resistor, I will have much to give thanks for
during the upcoming holiday!

Thanks,
Cyrus
Old 11-26-03, 01:15 AM
  #2  
Rx-hippie

iTrader: (1)
 
trainwreck517's Avatar
 
Join Date: Sep 2003
Location: Torrance CA
Posts: 2,076
Likes: 0
Received 0 Likes on 0 Posts
cpu or ecu? If its CPU I will take a look at it tomorrow morning.
Old 11-26-03, 01:30 AM
  #3  
cxr
Junior Member

Thread Starter
 
Join Date: Apr 2003
Location: North Carolina
Posts: 6
Likes: 0
Received 0 Likes on 0 Posts
CPU, not the ECU. As in, one electrical system after the next starts to fail, from the alarm to the warning buzzer to the seat belt lights, etc., which is a little discouraging until you realize the CPU runs them all.

Thanks,
Cyrus
Old 11-26-03, 02:53 AM
  #4  
Trunks are for corpses.

 
AbortRetryFail's Avatar
 
Join Date: Nov 2003
Location: St.Pete FL
Posts: 189
Likes: 0
Received 0 Likes on 0 Posts
My 86 GXL has been having similar problems, i was guessing maybe the solder connections.
Though my seatbelt light doesnt work at all. and the alarm sometimes works if i open then close the hatch.

Anyways, thanks for the idea! i'll have to look at the CPU on mine and see if there's any visible problems!
Old 11-26-03, 03:59 AM
  #5  
Full Member

 
Join Date: Nov 2003
Location: Silverdale, WA
Posts: 67
Likes: 0
Received 0 Likes on 0 Posts
hey cxr,
just posting because you are the first person I've seen in a long time with my name and exact spelling

sorry i can't help
good luck

-Cyrus
Old 11-26-03, 09:58 AM
  #6  
Former Moderator. RIP Icemark.
 
Icemark's Avatar
 
Join Date: Apr 2001
Location: Rohnert Park CA
Posts: 25,896
Likes: 0
Received 19 Likes on 19 Posts
I'll check later this morning for you on a FC66 CPU.

BTW, the 90-91 US spec convertibles use a different CPU than any of the other cars.
Old 11-26-03, 10:13 AM
  #7  
Senior Member

 
hpram99's Avatar
 
Join Date: Apr 2003
Location: -
Posts: 540
Likes: 0
Received 0 Likes on 0 Posts
I have a 90 'vert, I know the ecu's are different from any other n/a model, I'm not sure if the cpu's are the same though. I can look at it right now if I can find it (mine's on blocks waiting for me to rip out the engine anyway)
Old 11-26-03, 10:49 AM
  #8  
Senior Member

 
hpram99's Avatar
 
Join Date: Apr 2003
Location: -
Posts: 540
Likes: 0
Received 0 Likes on 0 Posts
oops, icemark allready made the remark about the cpu's being different. d'oh. I need to read closer...
Old 11-26-03, 12:20 PM
  #9  
Senior Member

 
hpram99's Avatar
 
Join Date: Apr 2003
Location: -
Posts: 540
Likes: 0
Received 0 Likes on 0 Posts
hey, I took the kickpanel off, took a look at the cpu, I have no clue on how to remove it. How'd you do it? the dead pedal is in the way, and some sheet metal.
Old 11-26-03, 12:57 PM
  #10  
cxr
Junior Member

Thread Starter
 
Join Date: Apr 2003
Location: North Carolina
Posts: 6
Likes: 0
Received 0 Likes on 0 Posts
There's a detailed description of how to remove it, with pictures, here:

http://www.teamfc3s.org/faq/

After you take it out, take the plastic cover off, and the large board (there are two smaller ones) is the main CPU board!
Old 11-26-03, 01:03 PM
  #11  
Former Moderator. RIP Icemark.
 
Icemark's Avatar
 
Join Date: Apr 2001
Location: Rohnert Park CA
Posts: 25,896
Likes: 0
Received 19 Likes on 19 Posts
Originally posted by hpram99
hey, I took the kickpanel off, took a look at the cpu, I have no clue on how to remove it. How'd you do it? the dead pedal is in the way, and some sheet metal.
10mm nut on top, remove that. Pop the top edge of the CPU out over the mounting bolt, then slide the whole thing up. There is a tab on the CPU that holds the bottom in.


Last edited by Icemark; 11-26-03 at 01:14 PM.
Old 11-26-03, 01:14 PM
  #12  
Full Member

 
Indy7373's Avatar
 
Join Date: Nov 2003
Location: Florida
Posts: 91
Likes: 0
Received 0 Likes on 0 Posts
I have a 91, I will check it as soon as possible. Hope I can help.
Old 11-26-03, 03:58 PM
  #13  
Senior Member

 
hpram99's Avatar
 
Join Date: Apr 2003
Location: -
Posts: 540
Likes: 0
Received 0 Likes on 0 Posts
hehe, thanks icemark, you make it sound so easy. I dunno what the previous owner did, but mine sure as hell doesn't look like that picture. The cpu and fuse box are there, but my cruise control is way over somewhere else. And there is a lot of very stiff wires that are in the way. Sorry, I'm not going to bother, it's going to require me to remove a LOT of things there to get at the cpu.
Old 11-26-03, 04:20 PM
  #14  
Rx-hippie

iTrader: (1)
 
trainwreck517's Avatar
 
Join Date: Sep 2003
Location: Torrance CA
Posts: 2,076
Likes: 0
Received 0 Likes on 0 Posts
Ok took a look off my 90GTU cpu, R1 is a 3.3 Ohm +/- %5 resistor. Color code Orange Orange Gold Gold. Hope that helps.

Last edited by trainwreck517; 11-26-03 at 04:25 PM.
Old 11-26-03, 04:45 PM
  #15  
Senior Member

 
hpram99's Avatar
 
Join Date: Apr 2003
Location: -
Posts: 540
Likes: 0
Received 0 Likes on 0 Posts
the gtu and vert have different cpu's, that resistor may not be the same.

edit: forgot key word: resistor, lol
Old 11-26-03, 04:53 PM
  #16  
Rx-hippie

iTrader: (1)
 
trainwreck517's Avatar
 
Join Date: Sep 2003
Location: Torrance CA
Posts: 2,076
Likes: 0
Received 0 Likes on 0 Posts
The scematics are basicly the same.. especial for first few resistors and capisitors. So I am pretty sure they are the same.. but I could be wrong.
Old 11-26-03, 05:16 PM
  #17  
cxr
Junior Member

Thread Starter
 
Join Date: Apr 2003
Location: North Carolina
Posts: 6
Likes: 0
Received 0 Likes on 0 Posts
I've just finished adding a 2.2 + 1.0 in series, to help dissipate heat, and it's fixed! Hi-beams, warning buzzers, etc. are operational again.

The resistor delivered power to a transistor that was gated by a zener, whose output powered the cpu chip. As it failed the voltage dropped and the chip gradually became inoperational. I was getting alarmed as one thing after another failed, until I realized there was a common point of failure.

Thanks very much for looking for me! I owe you dinner if you ever make it to NC.

Cyrus
Old 11-26-03, 05:29 PM
  #18  
Senior Member

 
hpram99's Avatar
 
Join Date: Apr 2003
Location: -
Posts: 540
Likes: 0
Received 0 Likes on 0 Posts
well looks like you were right trainwreck. my apologies.
Old 11-26-03, 08:09 PM
  #19  
Former Moderator. RIP Icemark.
 
Icemark's Avatar
 
Join Date: Apr 2001
Location: Rohnert Park CA
Posts: 25,896
Likes: 0
Received 19 Likes on 19 Posts
Originally posted by hpram99
hehe, thanks icemark, you make it sound so easy. I dunno what the previous owner did, but mine sure as hell doesn't look like that picture. The cpu and fuse box are there, but my cruise control is way over somewhere else. And there is a lot of very stiff wires that are in the way. Sorry, I'm not going to bother, it's going to require me to remove a LOT of things there to get at the cpu.
Convertibles have the cruise brain over by the ECU.
Old 11-26-03, 08:16 PM
  #20  
Rx-hippie

iTrader: (1)
 
trainwreck517's Avatar
 
Join Date: Sep 2003
Location: Torrance CA
Posts: 2,076
Likes: 0
Received 0 Likes on 0 Posts
Originally posted by cxr

Thanks very much for looking for me! I owe you dinner if you ever make it to NC.

Cyrus
Your welcome sir.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Lou Byer
General Rotary Tech Support
20
10-12-20 08:03 PM
wa11yba11s
New Member RX-7 Technical
3
10-16-15 09:54 AM



Quick Reply: Please look at your CPU for me



All times are GMT -5. The time now is 12:52 PM.