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IIVX Logic Board Problems

IIVX recap

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#1 wavedealer

  • 6502
  • LocationNashville

Posted 09 November 2017 - 08:18 PM

Hello everyone!

So I'm having some issues with 3 IIVX logic boards. I have re-capped 2 of them and one is still untouched by me. I will try to be methodical with the post...


I am doing all my testing with known working PSU, RAM and VRAM!


1. Bought as new and working. Installed and no booting at all. Did a re-cap. Now I get the startup chime, grey screen and then the Chimes of Death. No Sad Mac icon or error code diaplayed


2. Got from a friend unknown condition. Installed without any repair work. It powers on and chimes but then it goes into an endless restarting loop. Grey screen with an intermittent flicker.


3. Removed from the main computer at the studio. We use these IIVX machines to run the Harrison Series 12 NuBus cards so, needless to say, we want working Macs!

    The board was removed because the computer wouldn't power on. I did the re-cap. The board powers on but no chime, black screen.


I'm at a loss. Also, I'm hesitant to do the re-cap work on board #2 (restarting loop) as it does take time and I would hate to spend it on a fruitless effort.


Please help!!!



#2 techknight

  • 68LC040

Posted 10 November 2017 - 12:20 AM

But... you cant even begin to troubleshoot any of these boards without the preliminary recap. 

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#3 wavedealer

  • 6502
  • LocationNashville

Posted 10 November 2017 - 12:24 AM

But... you cant even begin to troubleshoot any of these boards without the preliminary recap. 

I have re-capped 2 of the 3 boards



#4 beachycove

  • 68020
  • LocationOntario

Posted 10 November 2017 - 01:10 AM

They have all been washed?

#5 wavedealer

  • 6502
  • LocationNashville

Posted 10 November 2017 - 03:31 PM

They have all been washed?


99% Alcohol baths



#6 Compgeke

  • 6502
  • LocationFairfield, California

Posted 10 November 2017 - 06:57 PM

It's going to sound odd, but, try a wash in the sink with dish soap then rinse with distilled water after a slight scrub. Cap goo gets everywhere and you'd need a lot of alcohol to clean 100% properly, without desoldering every component. Let sit for a day or two in the warmest, driest environment you can find. Here in California cars work great for it.


Also check the power supplies and recap them. The power supplies in everything from the IIcx through Quadra 650 are known for bad caps. 


Another alternative is see if you can't track down some Quadra 650s or maybe even just 650 boards. They share the same chassis as the IIvx but use solid caps that don't leak at all. If these are mission critical systems, it might be faster right this moment than trying to get the IIvx boards fixed. Do still fix them though, can never have too many backups when it comes to legacy equipment in use.

#7 wavedealer

  • 6502
  • LocationNashville

Posted 10 November 2017 - 08:18 PM

I do have multiple supplies with a known working one. Basically I have multiple IIvx machines and I'm trying to make a backup unit. So for my testing I have a known working unit with PSU RAM VRAM etc

and I'm using those components to test the logic boards I'm re-capping.

I have re-capped the third board, the one that was in a restart loop and it is still not working.


I do a complete submerging of the board in the 99% alcohol and lightly scrub then rinse multiple times.

I can try your method. Honestly I'm about ready to take a hammer to them in my frustration. Something seems intrinsically wrong to have 3 boards do a re-cap and none of them work.


Unfortunately for us we can only use either the IIvx or the IIfx for our console. I do have a few broken IIfx machines here to and I may move on to those as it seems there is more information here about them.




#8 IIfx

  • 68000
  • LocationVA, USA

Posted 13 November 2017 - 01:50 PM

The IIfx is an all around better machine than the IIvx. Faster, better case, better build quality.

A IIfx will not boot without 2 good PRAM batteries. This is the first thing you should check. There is a jumpstart procedure where you short a certain pin of the power supply but I cannot recall the the specific one, search for “Macintosh II jumpstart”, there should be a video on YouTube.

Capacitors on the IIfx are less of an issue. Most of the logic boards will be mostly tantalum and axial electrolytic. Check the two can capacitors by the RAM slots and PRAM batteries.

Also tagged with one or more of these keywords: IIVX, recap

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