IIfx acting funky, can't get it to boot right

[MysteryManBob]

Well you should get death chimes with no ram installed at all, so pull it all and see if that gets you anywhere?

You can try exercising the reset and interrupt switches a bunch of times.   I once had a stuck one, took 3 days of troubleshooting and a bunch of voltage readings to find that problem.  Now I make sure to hit those up before anything else!

What is worrisome is the floppy drives firing off like crazy.  That doesn't sound  too good. :/

My original 1MB SIMMs look pretty similar to what you have posted, except everything is flipped 180deg.  I suppose different SIMM designs exists rather than a standard single design.  Try looking up the datasheets on the chips and compare that they are functionally the same.

View attachment 22760

I've tried it with no ram too, no death march and the same spastic drive operation. That's why I think maybe I need one more rom to try

 

[gpbonneau]

I have 2 MacIIfx (all the two was upgrades from MacII to MacIIfx done in 1990). But the two motherboards are different.

The first version was made with about 12 small electrolytic caps (all leaks and recapped now) and the second with only 2 (recapped too now), the others has been replaced by tantale one by factory (on the 2 boards, there is a place for the two version of caps in a same place). 

According to your picture, it seems you have the second version, it may be necessary to replace the 2 small electrolytic caps...

First version :



Second version :



Différence in some place between the two version (out of factory, before to recap them) :

 

[Unknown_K]

The 2 caps in the second revision (if that is what we are calling it) work with the shutdown function of the machine. I had to rework both of mine after I found out my machines would not shut down using software (there is a thread about it somewhere here).

 

[MysteryManBob]

I have 2 MacIIfx (all the two was upgrades from MacII to MacIIfx done in 1990). But the two motherboards are different.

The first version was made with about 12 small electrolytic caps (all leaks and recapped now) and the second with only 2 (recapped too now), the others has been replaced by tantale one by factory (on the 2 boards, there is a place for the two version of caps in a same place). 

According to your picture, it seems you have the second version, it may be necessary to replace the 2 small electrolytic caps...

First version :

View attachment 22763

Second version :

View attachment 22764

Différence in some place between the two version (out of factory, before to recap them) :

View attachment 22765

View attachment 22766

Every cap is replaced,  one leaked ave lifted a pad with it so I had to bodge the trace.

 

[IIfx]

Were all of the axial caps replaced with high quality japanese caps? My IIfx wasn't quite right until those were replaced as well as the SMD caps.

The IIfx is the only Mac I know of with dual sets of pads for every cap; axial has SMD underneath, SMD electrolytic have a 2nd set of pads for SMD tantalum.

 

[MysteryManBob]

Were all of the axial caps replaced with high quality japanese caps? My IIfx wasn't quite right until those were replaced as well as the SMD caps.

The IIfx is the only Mac I know of with dual sets of pads for every cap; axial has SMD underneath, SMD electrolytic have a 2nd set of pads for SMD tantalum.

well no, I just got exact replacements for all of the axials and went with that. could that even possible be the culprit for this? I feel like this is a more serious failure than buggy performance, the problem really is I'm getting NO performance at all. still no raster, still no post, still no chime. just power.

secondly, are you suggesting I ditch just the radials for SMD, or replace the surface mount electrolytics with SMD too?

 

[MysteryManBob]

also, would it be a good idea to populate all these empty 47uf spots on the board or is that left empty intentionally?

 

[MysteryManBob]

also, would it be a good idea to populate all these empty 47uf spots on the board or is that left empty intentionally?

oh, I just realized mine actually has the tantalums in place. definitely a rev.B so nevermind