Quadra 840AV

[jrh_james]

Hi newbie here. I have a few vintage computers, Amigas mostly, but I never owned a Mac before and don't know much about them and I found a Quadra 840AV and I could use some advice. I don't have an Apple monitor or any other accessories just the tower.

There seems to be some life in it. When I power it on, it immediately makes a "chime" sound from the internal speaker - is this a good sign? The PSU fan runs and I can hear the hard disk spinning (but not seeking I don't think). At one point it seemed to go through a boot sequence and then made two beeps - what does that mean? It is not doing that any more.

What do I need to connect it to a TV or VGA monitor? I see there are adapters that convert the DB15 video out to HD15 VGA e.g.

http://www.ebay.co.uk/itm/390558193126

I connected the yellow phono socket marked "out" to a TV composite input but I didn't get a picture - should I?

 

[havokalien]

Need a DB15 to vga adapter or a mac monitor with DB15.

Problem is this is a mac that needs new capacitors installed. I am glad it does something for you as nothing usually takes more work.

I just recapped an 840av for myself and I will tell you its not too hard, with little effort the motherboard can be removed so you have access to the capacitors.

There is a service on Ebay that I know does it for a fee, I know the guy (not close to me) he does great work if you dont think you can order the caps and solder them yourself.

 

[MacTech68]

The adapter you linked to on eBay should do the trick with a monitor with a VGA port. Just note that you probably won't get the 840AV to run at an LCD's native resolution.

Finding one that still powers on and appears to boot is stroke of luck.

The yellow RCA socket is a video input. The "AV" in the Mac's model name denotes an "Audio Visual" Mac. These had a Philips chip which could encode composite video (NTSC and PAL), but considering it's age the digitization doesn't compare today.

havokalien is correct that for the machine to continue running into the future, you'll need to have the surface mount electrolytic capacitors replace (preferably with surface mounted tantalums which don't leak). The problem is, the electrolyte they leak is corrosive and eats away tracks and component legs.

I'm not certain you have an Apple mouse & keyboard, since you mention having no accessories. If you decide to get the Mac to SVGA adapter and proceed further, you'll at least need an ADB Mouse & Keyboard.

Remember, you'll be resurrecting a 1993 computer. Tracking down parts, upgrades, repairs etc will require some patience, time & money.

If you decide to go further, I wish you all the best luck in your venture!

PS - do a google search for "quadra_840av.pdf"

 

[bunnspecial]

A lot of folks consider this the "king" of 68K Macs, and with good reason. Although it was less expandable than some of the massive towers(900 and 950) it did have the fastest 68K processor Apple shipped-and if I'm not mistaken the fastest practical 68040 Motorola was able to make.

Once you get it running, if you want to spend stupid amounts of money on it buy some 16mb 30 pin SIMMs from OWC so you can really load it up with RAM.

 

[jrh_james]

Thanks for the replies. I don't have a keyboard or mouse for it yet, literally just the tower. I'll order a new PRAM battery for it as well. Old Mac spares seem hard to come by in the UK.

It has a composite video in and out. I thought I might get a picture from the composite out from boot.

 

[MacTech68]

...It has a composite video in and out. I thought I might get a picture from the composite out from boot.

IIRC, both are associated with the Philips DSP. So, essentially, no.

I wish Apple would sort out their Legacy Hardware Technotes. The "All Hardware" link is there but the link produces a 404

 

[jrh_james]

After tracking down a VGA cable, keyboard, mouse and replacement floppy drive I managed to get it to boot from floppy. After discovering that the hard disk spins up and then down on power-up I found out the head was "stuck" and by moving it across the platter with my finger I was able to get it to boot from the hard disk as per this video:

I though the problem might be caused by "sticky" rubber bumpers but after replacing them it did not help and the head seems to be crashing into the centre spindle so I think maybe the position of the head is not being sensed correctly.

Where can I get a replacement hard disk? What type do I need? I assume its 50-pin SCSI but can I use any brand? Given that 68-pin or 80-pin drives seem to be easier to find can an adapter be used to install a more modern drive?

 

[bunnspecial]

The easiest "plug and play" solution is to find another 50 pin drive. They are getting hard to track down, especially if you want very large sizes. The last bunch I bought were-I think-about 300mb and ran me $30 each(they were destined for earlyish 68Ks, so didn't care. Although not advertised as such, all the drives I received were I think Seagate branted Apple OEM.

68 and 80 pin drives will work with varying success with adapters. Good adapters are expensive, and cheap adapters are hit or miss. I'd love to get some 80 pins working, as I've rescued bunches of them in the past few years.

 

[jrh_james]

Thanks for the reply. I thought that even if I tracked down a 50 pin drive at a reasonable price it might be on its last legs due to its age.