Macintosh TV - Normal Chime then Immediate Death Chime

[facenda]

Hey all,

Trying to bring this Mac TV back to life. I had to jumper the Cuda just to get it to soft power, now it does and then gives the normal chime and then an immediate death chime, and stays on a gray screen. It has been recapped, ROM and RAM SIMMs cleaned and re-seated, but I can't get it to do anything different.

I tested the Mac TV chassis with an LC575 board, and it runs fine in there.

Any ideas on this one?

 

[Byrd]

Hi facenda,

An immediate death chime after the bong usually comes down to bad onboard RAM; does it do the same with the RAM stick removed?

In your pic, the onboard RAM module around U11 and UG9, UG10 look pretty cruddy - deep clean time around those areas and the other RAM modules.

 

[facenda]

I cleaned up the area around the onboard modules, and re-flowed all of them, but no change. The behavior happens without a ram stick, and also with a known working stick.

 

[MAC007]

I got one in with the same issue right now!

Mine was previously re-capped and washed in alcohol by someone. I just replaced the common caps with fresh tantalum capacitors.
Death chime persists.

I'm going to scrub it and ultrasonic clean it to see if it gets any better.
Otherwise if it doesn't, I guess I'll have to replace the on-board RAM...

I do have an identical Logic Board that is working to compare with luckily...

I'll report back if I figure it out.

**edit**

I forgot to mention I tried the ROM's from the other Logic Board, the issue persisted!

 

[facenda]

Let me know how that ultrasonic clean goes, I don't have an ultrasonic cleaner yet but was considering one.

At this point I am suspecting bad RAM or the CUDA, since I still have to jumper pin 27 to 5v to get soft power at all.

 

[bibilit]

Can also be the Egret chip or a bad trace.