Quadra 700 Death Chime - RAM Sockets?

[LazarusNine]

I get a chime of death every time I boot the Quadra 700 (just randomly started happening). I narrowed it down to a RAM issue. I've tried every variation of chips in each socket (with chips known to work in other machines). Is it possible for the entire array of RAM sockets to cease working? There's no dust and no bent leads from what I can tell. Board is clean. Tried a bit more isopropyl alcohol (99.9%) on the sockets. Still nothing. It's worth noting that without ANY extra SIMMs installed, the computer boots fine. Any ideas?

 

[TheWhiteFalcon]

VRAM or system RAM?

 

[LazarusNine]

System RAM

 

[uniserver]

pull the MB out, sometimes filth can collect under the mb,   

if the mb is over all filthy wash it and dry it off with a compressor.

if the PSU is filled with filth , blast it out with a compressor.

or swap the psu with another machine.

just because some ram might work fine in other mac's doesn't mean its going to work fine in the q700.

take a picture of the ram simms that you are trying to install in the q700.

 

[LazarusNine]

I should say that the stock RAM (20MBs) had been working perfectly well and then not. I have another batch of 20MBs as well, but none of those worked either. Tried my newer 4x 16MB SIMMs also. The MB looks clean as a whistle. Maybe I'll give it an isopropyl alcohol bath soon.

I've had the MB out about a dozen times trying to isolate the problem - it's clean underneath as well. It remains a mystery! I'll post a photo of the stock SIMMs in a few mins.

 

[Macdrone]

Strange, gonna keep an eye on this just in case.

Did you try removing/swapping the vram?  Maybe weak power supply needs a cap job? click the reset and interrupt switches a few times?  If one of the buttons is depressed it will power up to death chime.

 

[LazarusNine]

No actual updates except to say that I cleaned the board this morning - this time with a near-submersion method (I didn't have a container wide enough or enough isopropyl alcohol to fill a deeper one to submerge the whole board all at once). I isolated different parts of the board and went over them with a new paintbrush (over and over).

Here's a little toast to you folks!



When my wife told me to do the dishes, I don't think this is what she had in mind:

 

[TheWhiteFalcon]

Where's your CPU heatsink? Did you remove it?

 

[LazarusNine]

I removed it for the bath, yeah.

 

[TheWhiteFalcon]

Okay, just wanted to make sure. Otherwise, I was going to say I found your problem, lol.

 

[MJ313]

I've never done the dishwasher method... kind of never felt real comfortable with it... but my question is, should cpu's be removed if they are socketed? Seems some water could seep in there and cause some issues.

 

[LazarusNine]

I washed a Colour Classic board in the dishwasher, dried it and then let it sit buried in rice for about 24 hours. It worked extremely well and I might end up doing that with this Q700 board if my attempt with isopropyl alcohol doesn't work out. I would consider it a 'last-ditch' effort, though. I think there are quite a lot of variables to consider when using the dishwasher. I didn't bother removing the CPU, but it would make sense to if it's socketed.

 

[TheWhiteFalcon]

Depends on the pin material. Gold pin CPU's shouldn't be an issue.

 

[Macdrone]

I've never had an issue with the dishwashing, i do use rinse agent so no scale in the water sticks.  It would be the only downside.  i do shake off any water left and put them on a vent in my housetop dry off just in case (early on i was crazy and just shook the water off)  and still never had any issue.

 

[LazarusNine]

Well, I don't feel like this is any closure to the tale, but here's the state of things. I put everything back together and, despite cleaning the board thoroughly with isopropyl alcohol, I continued to get the Chime of Death when booting. So, in a desperate attempt, I installed and removed the RAM about a dozen times (something I'd tried many times before). Suddenly the machine booted. I've restarted a bunch of times and it seems to continue working. Anyway - I have no idea what it is. It's kind of annoying that I haven't sourced the root of the problem, but I guess I should be glad the Q700 is working? :-/

 

[Macdrone]

The fact of no battery but leaving it plugged in makes them happier.  Mine acted funny like that but after a few reboots after the wash and leaving it plugged in seemed to "warm it up" to function normally.

 

[techknight]

Something to throw out there. Power supply? Maybe keeping an eye on the power supply with an oscilloscope on a cold power up boot. if its really noisy, or has any ripple whatsoever, well, yea... 

 

[LazarusNine]

Thanks techknight. Gotta get my hands on an oscilloscope, but that's probably something worth having more generally anyway. I'll likely open up the power supply and make note of the caps with an aim to order some replacements.