Death chime and Simasimac SE/30

[takimoto]

Hi everybody.I've been visiting 68k LMA but this is my first topic.

I got a SE/30 and recapped it.And when I turned it on,I got both Death Chime and Simasimac.It seems CPU,System Bus,Rom and Ram are OK,but something is wrong around IF. Can you give me any idea where or what I would check?

Thank you.

 

[Macdrone]

Did you clean the board before putting on new caps? Did you search for SE30 and recapping here.

Most of these common issue are beating a dead horse.

Bad traces, do continuity checks, reseat ram and rom, caps in correctly, you sure you replaced them all? Start up with minimum ram.

All this is a start.

Good luck.

 

[takimoto]

Thank you Macdrone.

I washed the board.I put known working rams and rom,and checked sim sockets(rom and ram). This is not my first recapping.I recapped about 10 boards.I got many of them working by only washing and recapping.but some of them needed rewire.I succeeded to rewire some of them alsff course there are other boards  still needed to do (and enjoy) some more... But this is my first case getting Death Chime and Simasimac both.So I asked for suggestion.

Tkank you!

 

[techknight]

slow death chimes = cant see RAM = check the traces to the RAM slots, the buffer IC just below the slots near one of the good leakers, and then check the 74F258s for stuck logic gates. 

 

[uniserver]

i have a iifx here with slow sad mac,   trying to figure this one out.  normally a iifx will happy chime even if there are no ram simms installed, this one slow sad macs no matter what i do.    i was wondering if the memory controller ic was dead   maybe static discharge?  this iifx only had 2 smt tin can caps, the rest are tantalum from factory, in this case. 

 

[techknight]

I am not familiar with the IIfx at all. never seen one, owned one, or worked on one. 

But, I know the SE/30 ROM will produce slow chimes with no RAM, or RAM cells that cant be seen. the modified ROM SIMM is a basketcase, sometimes chimes with death chimes, or just plain death chimes. 

 

[uniserver]

yeah the 8mb dougg3 rom simm is a basket case with the se/30's its like 60-70% of the se/30's will just not boot / chime with it in there…  to where 100% of the time the 2mb dougg3 simm will work.

i should send you a 2mb dougg3 rom simm, i bought some more.

its even got red lights for the Jolly Roger's eyes. kinda cool!

 

[takimoto]

Thank you tachnight and uniserver.I'm so glad getting reply from 2 tops of this forum.

I didn't know it is known as Slow Dead Chime and didn't know SE/30 can ring Dead Chime with bad conection to Ram Sim because my SE/30 logic boards didn't chime anything without Ram Sims.I'll check around connection to Ram Sims.
I had been interested in dougg3 rom sim.It will be cool if I could code my own diagnostics code.

 

[techknight]

Well, the ROM SIMM  has to be there for a chime. they will chime, but chime of death without RAM. if you remove the ROM SIMM, well.... 

 

[takimoto]

Hi! All!

I checked connections around RAM SIMM<-> 74258 <-> BUS, they seemed to be good. I also looked into signals around RAM SIMM and found that DRAM refreshing address signals were strange compare to working board.Is GLUE Chip dead? or is there other possible culprit?

Thank you.

 

[techknight]

It can if one of the traces is bad to the GLU. you need to check them all on the 30pin simm. Trace them back through. Also probe the 74f258s with a scope. Ive seen those chips go cactus causing a gate hardover allowing only one pin signal through regardless of the gates select line. Check it. See if the input to output signals are following the truth table based on the mux select line.

 

[takimoto]

Thank you technight.After yor suggestion,I'v been watching signals around 74F258s with logic scope and found some strange things.

1)Befor last my post,I'd been cheking with 4M RAM SIMMS which always gave me Slow Sadmac.After that I started cheking with 256K RAM SIMMS,and which gives normal chime onece about 8 times(but seems failed soon after chime...).looks like something wrong with higher address buses.
2)Watching signals around 74F258s,somehow 2 couples of Address Buses(A(18) and A(19),A(20) and A(21))show me same pattern.I checked registance between these lines but they aren't closed.
 
I'll continue checking around 74F258s and Address Buses.And I'll be glad any idea you give me.
 
Thank you.

 

[uniserver]

also one of the nice things of the 475/605 is you can remove the onboard ram and it will still run just find from a ram simm.

i would check there is a spot were there is 2 caps right next to the onboard ram.   they spill their goo into the ram ic there.

i would wash the board with hot water and soap and give it a good scrub and then give it a hot water rinse... and a compressor dry.

 

[techknight]

Thank you technight.After yor suggestion,I'v been watching signals around 74F258s with logic scope and found some strange things.

1)Befor last my post,I'd been cheking with 4M RAM SIMMS which always gave me Slow Sadmac.After that I started cheking with 256K RAM SIMMS,and which gives normal chime onece about 8 times(but seems failed soon after chime...).looks like something wrong with higher address buses.
2)Watching signals around 74F258s,somehow 2 couples of Address Buses(A(18) and A(19),A(20) and A(21))show me same pattern.I checked registance between these lines but they aren't closed.
 
I'll continue checking around 74F258s and Address Buses.And I'll be glad any idea you give me.
 
Thank you.

Uniservers board gave me the same exact fits, I never did figure that one out. Intermittent slow chime/regular chime is the most difficult one to figure out. 

 

[takimoto]

Thank you uniserver.I washed this board after removing old caps.but I'll check about goo again.

 

[takimoto]

Thank you techknight.

Oh gosh! If you did not figure one out,It will be extremely hard for me.I have some idea now.after trying them,I'll take time now and seek other idea.

I'm very sorry I miss spelled your name on my last reply.

 

[takimoto]

Hi all!.

I'm still cheking this board when I can get time.and there are something I found and wonder.

I thing all F258s are good.when I was checking them with logic scope,once in about 10 reset,this board wipes Simasimac and shows gray background and chime death chime.

And I compared signals around F258s with working board,I found mux signal is different between this board and working one.

I'm studing about mux signal,Any idea you got,I would love to hear.

Thank you.

 

[techknight]

sounds like an intermittent connection to one of the ICs. 

 

[takimoto]

Thank you techknignt.

I'll check about intermittent connection,maybe start from around UH7.I'll report when I find something.