mac se fdhd help

[grandslam]

just purchased a macintosh se (fdhd) and originally didn't care if it started or not (it was only $10) but now I would like this little guy to work. It starts up pretty good makes the start up sound and then displays these vertical bars with what looks like a sad mac and some error code
I cleaned the roms, re seated the ram, but to no avail. I also bought good used ram (4x 1mb) but once installed I received a checker board like pattern. I realize just looking at the photo might not say much but who knows... any help would really be appreciated... thank you.

 

[nvdeynde]

Error code "0000FFFF" "00000002" points to a Ram issue.

There are several versions of the Mac SE logic boards around. The logic board's standard setup is for 1MB of ram = 4x 256KB modules.

If you want to use another setup, you either have to change a jumper near the ram modules or remove 1 or 2x resistors near the reset/interrupt switch.

It's best if you post a large photo of the PCB so we can see if the current setup is correct or assist you which resistors need to be removed.

 

[grandslam]

Thanks nvdeynde!

I will have to get a better camera, but I will take another pic of the logic board (close up). I am suppose to have 4 1MB rams and the jumper is removed (because of the 4MB total). But I could not find any additional info (speed, etc) on the ram chips. I wanted to find out if 1MB ram chips were of different speeds then I could put them in the correct place. Who knows, they might not even be 1MB of ram. I do not have any equipment to check if the ram chips are even good. I did buy 4 used 1MB ram chip from a reputable reseller... 3 were the same brand, and the last one was of a different company. Hmm, okay... I get those pictures. Thanks again.

 

[grandslam]

Okay, here is a link to more photos, but using the same camera on my phone. I will have to borrow a better camera, maybe tomorrow... if needed... =)

In this photo, you see a jumper, I put that there to test, but there was no jumper originally. BTW, with the jumper in this setting its the same as "no jumper".



No jumper, original setting, with original memory

http://www.flickr.com/photos/29771939@N05/7986632717/in/photostream/lightbox/

Newer (used) memory I picked up (when I put these in, I get a checker board effect...

http://www.flickr.com/photos/29771939@N05/7986633803/in/photostream/lightbox/

 

[nvdeynde]

I assume the Mac came with ram installed. Didn't this memory give the same error ?

Try installing only 2x modules in Bank A and set the jumper to 2MB ( 2x 1MB module ).

As for the memory modules you photographed: I have never seen this brand before. They are probably 1mb modules of 70ns.

Both erros you had, the Checker Flag Pattern and Jail barr with smiley/sad Mac, point to memory errors.

So either the ram is bad or you got a faulty logic board if it's not working with the jumper for the memory setup in the correct position.

 

[grandslam]

Yes, it came with memory installed (4x - all banks filled). I just didn't know the ram size of each. I just assumed they were 1MB (no size labels on them) each because the jumper was not present, usually indicating 4MBs. I started it up and everything sounded normal, but I received the jail bar screen.

Okay, I will install only 2x modules in Bank A as you instructed and see what happens... thank you very much for your instructions and sharing your knowledge...

 

[grandslam]

I put a 1MB ram in slot 1, and a 1MB ram in slot 2 (the first row) with the jumper for 2MB and screen was checker board. I did this with each of my ram modules. Then I did the same thing with slot 3, 4 while leaving slot 1,2 empty (just the opposite of the first round with slot 1,2) and leaving the jumper set for 2MB and the screen was completely black but I could still hear the boot process in the background. The original mac se service manual said you didn't need the jumper for 2MB/4MB so I tried again without the jumper and I still got the checker board screen. I first thought maybe slots 1,2 are bad but I only get the jail bar screen w/ all slots occupied with a 1MB ram. and all other combination display a checker board screen (except when I leave slots 1,2 blank then the screen goes black). It certainly is difficult w/o the right equipment to testing things... any thoughts? Maybe I should just get a new logic board that is working and save some time... hmm.

 

[8bitbubsy]

Try to dismantle all of the socketed chips and clean the chip pins with isopropanol alcohol and reseat (make sure you put them back the same way as they were, having the little orientation notch in mind). Clean the RAM pins too, and maybe the RAM socket pins with an old toothbrush + alcohol again.

Look for any signs of corrosions/leakage near the PRAM battery. Also measure the axial capacitors with an ESR+capacitance meter if you have one (desolder the positive pin first for a guaranteed OK measure, the ground pin can be hard to desolder).

You should also check if the PSU voltages are in an acceptable range, be sure to measure this while the unit is on and connected to the logic board -- the PSUs needs certain load to have a stable output voltage.

 

[grandslam]

:beige: Thanks 8bitbubsy...

I was actually thinking of taking my whole mac apart and cleaning it. I wanted to restore the case, keyboard and mouse (slight yellowing). I found this site and it looks pretty promising http://retr0bright.wikispaces.com/. As for testing it, I have no such equipment as of yet, but maybe in the near future. It would be way easier for sure if I could test the chips instead of using the trial-n-error method. I did remove the 3 roms in the center of the board already and gave them a light scrubbing but I didn't use any alcohol, but thanks to you I at least know which one to buy now... thanks.

 

[grandslam]

my mac is now working! There was something wrong with the first memory slot on the motherboard. So I ended up buying a new one from Retrotechnology.com, the owner Herb Johnson was very helpful. He found an fdhd board for me and sent it right away. I installed it and "bong" and then I heard a strange "Beam me up Scotty" and then there was that all too familiar mac desktop. Thanks *everyone* for all your help and helpful tips.

I am now going to try the Retr0Bright mixture to restore my mac shell to its original color... the coffee stain yellow look is not working for me =)