Recapped SE/30 with Simasi-Pattern and chimes of doom

[sbreit]

Hi everyone!

Some time ago, I got a SE/30 that someone gave away. Only thing I know about its history is that it "stopped working". Back then, it showed horizontal bars and chimes of doom (very quiet). A few days back I've opened it for the first time. Everyting was quite corroded from moisture.

Well, I cleaned everyting, removed the corrosion as good as I could and exchanged the capacitors (with tantalum ones). Chimes of doom will play louder now, but I'm still stuck with horizontal stripes and chmes of doom.

I think I can rule out RAM and ROM because I've tried it with RAM and ROM from a working SE/30 with no change in symptoms.

I also checked the ICs and none of them seems to be getting particular hot.

Any idea what else I could try? xx( xx( xx(

Steffen

 

[onlyonemac]

There's a site (I'll post the link if I can find it) which documents all sorts of SE/30 issues.

EDIT: Here it is! http://www.biwa.ne.jp/~shamada/fullmac/repairEng.html

From that page, it says:

Symptoms(1) Early Symptoms

No startup bongs

Irregular fine rasters, usually vertical although variable

Delay of startup after power-on

Unexpected intermittent restart

(2) Terminal Symptoms

No startup

Horizontal stripes

Diagnosis and Background

On startup, Power-ON reset signals are generated endlessly.

The underlined text could case COD in most cases-I've heard that a reset signal at startup will cause a COD (normal Macs do it if you press the reset button at startup).

 

[techknight]

Check all circuit traces of the RAM, the RAM's mux, and the databus.

 

[sbreit]

There's a site (I'll post the link if I can find it) which documents all sorts of SE/30 issues.[...]

Thanks for your reply, but I don't think I'm looking at a "real" SimasiMac here. As far as I understood, in that case there would be no bong at all.

 

[sbreit]

Check all circuit traces of the RAM, the RAM's mux, and the databus.

That was the direction I was heading. I'll check all the data and address lines and if that doesn't bring up anything I'll check out the muxes. Luckily a friend of mine has an eight channel logic analyzer ;D My other SE/30 had a shift register that was gone, so I hope its just something similar...

What about the GLUE chip? How common are problems with it?

 

[onlyonemac]

I reset at startup will cause chimes of doom-full stop. So yours is most likely a real Simasimac :simasimac: . Just try the suggested solutions as per the linked webpage.

 

[JDW]

Sounds exactly like the re-capped board of mine that continue to exhibit stripes and the death chime:

I shipped that board plus one other recapped-but-still-dead board to techknight in May 2012. He suspected the Bourns filter, so I shipped him 6 pieces. Did you ever get either of my boards working, techknight?

viewtopic.php?f=7&t=18026&p=175476

 

[techknight]

One of them, Never had any luck on the other. it wasnt remapping ROM on reset. (bad Glu/FPU). Second board: The cap that sits right in front of the RAM slot had leaked of course, but the fluid corroded the connections on the first RAM slot where you cannot see it.

This will cause simasimac.

 

[JDW]

Was the board you repaired the one with the socketed CPU by chance? (I was hoping to get that one repaired the most.)

Thanks.

 

[techknight]

Yes. I may be getting a donor board for the CPU/GPU/GLU.