Quadra 840AV problems, need help

[MacNostalgic]

Hello guys,

I'm new on this forum.

My first Macintosh I haved used was my dads one. A Macintosh IIcx in 1991, IIRC.

It was a pleasure to use this easy to handle computer.

For a couple of weeks I bought a Quadra 840AV on ebay. It was sold as damaged.

Without a HD, it only appears the disc with "?" on the screen.

That's because I bought the AztecMonster, additionally.

The CF card isn't formatted, yet.

At first time, the startup sound chimed.

Now it doesn't. Don't know why ...

I have a Mac OS 8 68k CD. But on startup the CD-ROM doesn't scan/ rotate.

Dito. the floppy drive. It just throw out the disc without scanning, IMO.

The question is now:

1. Why there is no startup sound?

2. Have I to set jumper on the AztecMonster?

3. Why doesn't the Mac scan the CD/ disks?

Has someone experience with this kind of failure?

Thanks for your help

MacNostalgic

 

[Trash80toHP_Mini]

Welcome aboard!

Try re-seating all the connections inside the case, especially the RAM and ROM SIMM (if any) and give it a go without the Monster.

If there's no startup or death chime, it's my understanding that you're getting a very low level hardware test failure, but I'm no expert.

 

[MacNostalgic]

Hello!

Thanks for the input!

I'll give it a try!

Besides this, it was possible for me to reset the parameter RAM and it was possible to powerup the Mac with the power button on the keyboard.

IIRC, the startup chime sounds after I plugged the Monster in.

What happened after this, I plugged the monitor in a asante card, I tought it was the graphic card with a DB15 HD15 adapter.

Then I started the Mac, screen was black, of course. No startup sound

Hard to believe I destroyed something ... ?

Then I put a MacPicasso in the Mac, then appeared the disc

MacNostalgic

 

[beachycove]

I have seen this behaviour in two 840av machines. In both cases, capacitor leakage was the problem. I washed the logic boards and both booted consistently afterwards.

Termination of scsi drives and scsi ID settings are crucial with any drive in a Quadra. The mysteries of scsi are not called scsi voodoo for nothing, however, so there may be some ritual, repetitive dancing and a fair deal of invocation of ye gods involved in checking and rechecking, setting and resetting these things. On an 840av, that, alas, is not an awful lot of fun.

 

[MacNostalgic]

Hello beachycove,

how did you clean the mainboard?

And I have a service manual auf the 840AV, but the pics are very bad, so I didn't know how to disassemble the 840 correctly :-(

And what kind of error was shown by your Quadras in detail?

It's really hard for me to detect the error correctly, because I didn't know if it's normal that the 840 throw out every diskette and if this is normal when the capacitors are leaked? I have also tried a System 7.5 disc.

Don't know where to start and how to isolate the error.

Thanks in advance

 

[beachycove]

First things first. Cleaning the board would be a last step.

The manual for the Aztecmonster, which i found online, says that there is a termination jumper. Set termination to ON. Next, set the ID to any number other than 3. 0, 1 or 2 would be good. Then try to boot and report back.

Spitting out a floppy can mean that the floppy drive requires servicing, i.e., careful cleaning and careful lubrication. It is likely that you will need a working floppy drive to install system software, even if you have the CD, so this is also important.

But first set termination and ID, and tell us the results.

 

[MacNostalgic]

Sorry for the stupid question,

But the drawing in the manual differs from the connector on the pcb ...

Have I to set to jumpers? One on the T marking Aand one on a number? See the pic attached. Only one jumper is set.



And I have taken a picture of the rear of the CD-Drive. On the rear, I have nothing changed.

I don't know if these jumpers are correct??

 

[beachycove]

Termination is ON, which is right. You could now try a) putting a jumper across the 1 pins to set the ID to 1 (maybe the card has no ID=0); B) taking off the Termination Power jumper of the CD drive; and c) disconnecting the CD drive and see if you can boot from floppy. Try booting between these steps, as either might have an effect; if not, put it back as it was and await further instructions!

Others will no doubt chime in in due course as to the correct method of troubleshooting, but there is already much information on this forum if you search.

 

[MacNostalgic]

The access LED of the monster was blinking.

Have disconnected the CD.

No booting from floppy.

The floppy isn't spinning. Dito. The CD drive.

Both drives are damaged? Nearly impossible?

Second problem, I have 7.1 but no system enabler and don't know how to copy it on a disk.

I think the best thing I can do is to buy a working machine and then test the floppy and CD on the working machine.

So I can isolate the problem.

I will call also people here in germany with these old machines. Maybe the can download and copy 7.5.3 on disk.

And the startup chime comes at the first time I powered the Mac up.

Then I moved it upstairs to the display. Then no startup sound.

What a disappointment.

 

[Trash80toHP_Mini]

HRMMM? In that case, I wonder if RFI from the unshielded CRT/Monster duo might be causing the problem? Try making an RFI shield for the Monster or using it externally again.

Magnetic interference from the CRT could be the problem as well. The electronics on the monster could be a LOT more sensitive to electromagnetic interference than the usual inhabitants of the SE/30 expansion slot stack. The processor on board the monster is likely operating at a clock rate something like a couple orders of magnitude faster than any SE/30 PDS Cards packed into that bucket.

< scratched head and decides to warm up his first cup of coffee >

Dunno, top-o-the mornin' WAG posted above . . . xx(

< returns w/coffee >

Could the RFI from the monster we whackin' your SE/30's Processor? :?:

OOPSIE!!!!!! That's what I get for posting while I'm still asleep. :I It's not an SE/30, but the plastic chassis of the 840AV is probably just about as electromagnetically opaque as the air in a Compact Mac Bucket. So CPU and I/O subsystem whackage may still be the culprit.

 

[beachycove]

Is this your only Mac? In other words, do you happen to have a functional scsi hard drive with a 68k system installation on it, 7.5 or above? That would be useful for testing purposes. The custom card is likely to be temperamental.

However this may be, as I said some posts ago, I have had two 840av boards that needed washing. I did mine in a dishwasher (empty, no soap, and yes, it works), but search for alternatives if you do not have one. It is a common practice. Replacing the capacitors is a longer-term solution, but that may not be necessary in morder merely to make the machine boot.

Logic boards were washed with water at manufacture, so it does no real harm; you can also do the cleaning with rubbing alcohol, but I have not found this method any more effective than using simple water.

 

[MacNostalgic]

In a normal dishwasher, really?

Only water?

A have completly disassembled the 840AV.

Mainboard looks good so far. But someone have tried to change the elcos.

I have powered up the mainboard without a card or RAM. Only power supply and speaker. Still no startup chime :-(

I will make pics of all and then put all the cards in the dishwasher.

 

[beachycove]

The word "elcos" means capacitor, right? In this case, the problem may be that a poor job was done. However, the logic board was probably washed by the previous owner as part of the attempt to fix the machine....

I am not able to advise you further about how to test/ repair these components but there are others among us who could.

I will say that in my case, capacitor leakage was particularly noticeable in the area where the main power connector plugs into the board. It had bridged the large traces visible in that area. Take a look and see if yours is the same. It is possible that the previous owner did not wash the board as a whole, but just cleaned around local areas and missed this one.

 

[MacNostalgic]

Yes, alot of capacitors seemed to be changed, but badly soldered.

I don't know the right word. The soldering points have noses.

If the mainboard was washed, I don't know.

The RAM modules are definitely not.

The battery has full power, also.

The only working 68k Mac is a Powerbook 180c.

Sadly no ethernet connection, so I don't know how to connect to my router :-(

I don't want to give up that quick.

 

[MacNostalgic]

Same result after washing :-(

No start chime, no floppy spinning.

But now I have seen on the backside, there are three red SMD glue points without resistiors on R218 - R220. Nearly the CPU socket pins.

The solder points are looking normal. Nearly no solder. So the resistor are not torn off.

Is there anywhere a BOM (bill of materials) or a repair guide of the Quadra?

Thanks for all the input

 

[MacNostalgic]

Maybe someone has made schematics of the board that I'm able to retrace the signals.

The next step is to resolder the capacitors.

To my understanding:

AM I correct that to see the disk with "?" is a good sign or it has no meaning?

And the missing startup chime may have to do with badly soldered capacitors.

I have ordered "Apple Macintosh Level 1 schematics", but my fear is there is no Quadra schematics inside :-(

 

[beachycove]

The disk with the ? is a good sign.

Your speaker is definitely plugged in, right?

 

[beachycove]

Further random thoughts:

1. Are you sure that the board is dry? Most of us would wait for some days after washing to attempt startup!

2. Clear the PRAM. To do this, turn on the machine and immediately and simultaneously press CMD Option P and R keys, keeping them down. If the machine is working properly, it should restart. This may or may not be needed, but it can do no harm and it is a common practice.

3. To start from the CD drive, the 840av does not, in my experience, respond to the usual holding down of the C key. You need instead to press the power on key, and then immediately and simultaneously press CMD Shift Option Delete, keeping the keys down until (hopefully) the machine boots from CD.

CMD is the key with the Apple on it.

 

[Trash80toHP_Mini]

1. Are you sure that the board is dry? Most of us would wait for some days after washing to attempt startup!

Sorry about that slip up, I was going to chime in about running a full wash cycle to make sure all the soap is flushed out before board "rinsing" for a full "wash" cycle . . .

. . . I'm overly cautious and impulsive at irregular intervals about troubleshooting processes . . .

I meant to add that I usually blow a board "fairly dry" with compressed air and then wait a couple of days before testing.