Macintosh IIcx to quadra 650: 33mhz.

[Macbuk]

About 3 months ago I bought a macintosh IICx from germany.

During early tests i noticed ADB malfunctions: a lot of mouse and keyboard's intermittent freezes that i was unable to resolve with F3 fuse bridging.

So i replaced motherboard and decided to upgrade CX to Quadra motherboard with a little case surgery. At the time I had to decide between Quadra 700 and Quadra 650 motherboard (i had both): because their form factor is basically the same, i have chosen more powerful Quadra 650 @ 33 mhz mb: the procedure was successful.

Here's some pics.

http://img145.imageshack.us/img145/4695/pezzilq3.jpg

http://img120.imageshack.us/img120/5293/centrisinogc1.jpg

http://img262.imageshack.us/img262/1013/centrisino2qe5.jpg

Now i'have some doubts about CX power supply reliability with this motherboard because Q650 upgrade is not suggested for IIci/cx on micromac web site: http://www.micromac.com/FAQ/faq_q650_upgrade.html

Could anyone tell me quadra 650 and quadra 700 power supply specifications if known? I know that CX/CI powersupply are not so reliable and i would not destroy it.

Do you think that Quadra 700 motherboard could drain less power than a 650 mb?

Thanks...

 

[Quadraman]

Having just done a 700 board swap into a IIvx case after trying to put the 700 board into a IIci case and deciding I liked the sturdier and bigger IIvx case better, I can say that the power supplies from all three are the same or near enough that they work without issues. Not sure if they used a different one in the IIcx, though. The IIvx,vi, Performa 600 and Centris-Quadra 650 all use the same power supply, I am sure. My 700 project is happily running with maxed RAM, a 601 upgrade, internal hard drive, and a pair of cooling fans salvaged from a clock chipping kit on the IIci power supply.

I would use a 650 board over the 700. You can get a lot more RAM into a 650, and the 700 board does not have a CD audio plug so you won't be able to listen to music CDs, if that's important to you (maybe if your CD ROM drive has a headphone jack, but not through the system). If I had known when I bought the 700 board that the 650 was the same form factor, I would have bought a 650 board instead of a 700.

Oh, and I wouldn't bother buying a conversion kit to do this. All the parts you need are readily found on ebay or from members of any Macintosh forum like this one probably for a lot less money than you would pay a retailer. There hasn't been a response from Micromac in a long time, anyway. There was a thread about it recently. The website hasn't been updated since 2000, so don't place any orders with them.

 

[Macbuk]

My 700 project is happily running with maxed RAM, a 601 upgrade, internal hard drive, and a pair of cooling fans salvaged from an clock chipping kit on the IIci power supply.

Thanks Quadraman for your answer.

My own IICX and IICI have same PS specs so my "frankenmac" [] ]'> powersupply should be enough powerful.

I would use a 650 board over the 700. You can get a lot more RAM into a 650, and the 700 board does not have a CD audio plug so you won't be able to listen to music CDs, if that's important to you.

I fully agree, howewer i've a pair of external cd300 scsi for this.

I've to say that I'm not a big fan of 040, i like mainly "pre '90" macs but 040 performance with 3d retrogames like Wolfenstein or Pathways into darkness is astonishing when compared to IIFX or IICI. [}] ]'>

Oh, and I wouldn't bother buying a conversion kit to do this. All the parts you need are readily found on ebay or from members of any Macintosh forum like this one probably for a lot less money than you would pay a retailer.

it's true, but here in italy the businness of vintage computing is a little overinflated. For example in USA you can find a "nude" IIGS for 13-20 $. Here you have to pay at least 50-60 €. Unfortunately USA models are 110V and shipping prices are prohibitive.

My aim is purely emotional, but here we have some "collectors/ebay sellers" promoting commodore/sinclair/apple (mainly II and compact macs) "businness".

 

[Quadraman]

Many computers have dual voltage power supplies that are switch selectable. All you need is the proper power cord to fit your outlet. Shipping charges are usually a deal breaker for most people, especially international shipping, and I know prices are much higher in Europe. Computers sell for a lot more money new there than here so they depreciate more slowly. Some machines are also harder to get because not as many were sold there. My experience comes from watching the UK market, but similar conditions exist all over Europe. Prices are just as high on ebay France and ebay Germany.

 

[MacG4]

yeah i did a similar project myself. installed a quadra 700 motherboard in a Mac iicx case

 

[equill]

... Could anyone tell me quadra 650 and quadra 700 power supply specifications if known? I know that CX/CI powersupply are not so reliable and i would not destroy it.
Do you think that Quadra 700 motherboard could drain less power than a 650 mb?...

IIcx, IIci and Quadra 700 all use the same Delta or Astec PSU:

+5V @ 1mA continuous (TRKL: lost when the diode below fails)

+5V @ 12A

-12V @ 1A

+12V @ 1.5A

The Astec AA15831 is commoner, but has a potential fault in that the bias diode for the sawtooth oscillator may go low (in forward voltage drop) with age, and so disable the oscillator. It can be remedied with a second diode in series, but ... It is fiddly, and requires that you make certain that the filter/storage capacitors have been/are discharged before you burrow inside.

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