| Click here to select a new forum. |
| Mac IIfx turns on but no chime |
Posted by: Pitou on 2017-02-07 08:30:20
Hello,
I have a Mac IIfx that I just recapped. I now turns on, but I get no chime/sound at all.
I tested the ROM SIMM and RAM simms in another Mac and it's fine.
Any ideas/pointers?
Thank you.
Pitou!
|
Posted by: mac-man6 on 2017-02-08 18:17:45
Are you sure the speaker was reconnected after recapping?
|
Posted by: Pitou on 2017-02-13 06:06:52
Yes the speaker was connected. I am lucky enough to have another logic board. I replaced many logic chips and still no luck. I'm thinking the main 68030 CPU might be blown. It happened before on another Mac II. I played around with the scope, but it's a bit hard without the schematics.
I'll hunt for a new CPU.
Do you know if I should at least get the startup chime *without* the 68882 co-processor?
Also, to get it, I must have at least for banks of RAM filled. Is that right?
Thank you.
Pitou!
|
Posted by: CelGen on 2017-02-18 09:06:00
Minimum of one bank of ram filled but no idea bout the missing processor.
Verify you don't have leak damage somewhere.
|
Posted by: zuctronic on 2017-02-22 13:57:10
Any update on this? I have the same issue with a Mac IIfx.
|
Posted by: Pitou on 2017-02-24 11:11:03
I replaced the CPU but still the same. I'm about to try a new 68882 FPU.
My guess is that the fx needs both the CPU and FPU in order to boot what's in the ROM SIMM.
Will let you know.
Pitou!
|
Posted by: zuctronic on 2017-02-25 15:39:41
Ah, in my case it turned out to be the ROM. I tried a ROM-inator II from BMWOW and it's working now.
So now the question is: Is it possible to repair the bad ROM? How do I go about troubleshooting it? I don't see any replacement Mac IIfx ROMs available anywhere but I'm interested in restoring OEM parts as much as possible..
|
Posted by: techknight on 2017-02-26 17:16:58
if the ROM is bad, then it COULD be suffering from bit-rot if it started life as a PROM so it works exactly like EPROM but with no window. So you burn it and its done.
if its mask-ROM its likely something different like failing buffer circuits etc internal to the IC.
|
Posted by: zuctronic on 2017-02-27 05:28:18
I took a closer look at the Apple ROM SIMM and noticed the contacts were looking pretty dull. I wiped them down real good with some IPA and now it's working fine!
P.S. - A/UX doesn't boot with ROM-inator II
|
Posted by: Pitou on 2017-03-09 09:50:47
I'm now getting the startup chime.
However after a couple of seconds, I get another sound/chime.
I tried the RAM simms in another MAC and they are good.
Can you tell me what it could be related to?
Thank you.
Pitou!
|
| 1 |