Live Stream With Amiga Bill

LIVE STREAM Sunday October 18th 2pm EDT/6pm UTC/8pm CET – Commodore Amiga Hardware Talk with Electronics Expert Acill Paul Rezendes ! LINK: https://www.twitch.tv/amigabill

For those that missed the live stream here is the reply! It was some great fun. https://www.twitch.tv/videos/774780199

Home and Catching up!

I am home again for awhile (I hope at least and didnt just jinx myself here). Over the last weekend I got several things finished and out. Hopefully this means I can start to get to the more difficult items here and get them taken care of! As I say often, thanks for the support and understanding!

I’ve been streaming on Twitch as well. Nothing exciting or narrated much. its me working and a live feed going is all. If you are interested in checking it out you are welcome. The link to my twitch channel is here: https://www.twitch.tv/acill and for a more personal way to watch me I have been doing things over at my Patreon geared more and teaching as support. You can find that here if you want to join. I have a very low entry point and dont expect much at all. That can be found here: https://www.patreon.com/acillclassics

And lastly, I even put things on my YouTube channel from time to time here: https://www.youtube.com/user/Acill

MNT ZZ9000 Batch 1-4 1V8/3V3 Short Fix

If you have a ZZ9000 card for your Amiga you need to have this done ASAP! I am happy to offer the fix free of charge for those of you here in the USA. All I ask is you please cover the return shipping back. I will of course accept any tips, but payment for such a simple repair isnt required. I would rather see it gone right and back to you quickly!

I have also reprinted the information from the MNT site with a direct link so those of you wanting to do it yourself have the information available. I will also be doing a video on this fix and post it here publicly as I am doing it on my personal ZZ9000. As always, thanks for the support and have a great day!

For information on this fix directly from the manufacturer please follow this link: https://notes.mnt.re/s/BkBGokgMw?fbclid=IwAR2GZqjfbyEpOkov_p2V4-KtQyvl-tFs_c4kmNJdZBDa3fbhJoyBOzYq8bw

Published by: MNT Research GmbH, Berlin.

What’s the problem?

MNT ZZ9000s revision R-1 and R-2 have a design error that shorts the 1V8 and 3V3 supply voltage rails of the ZYNQ module together by a wrongly connected pin on connector U12 (pin number 93). The pin is documented as XADC power supply in the MYIR documentation, but it is not specified that it is already internally connected to 1V8. This is how the mistake happened.

The problem is that the mistake leads to various supply and I/O voltages connected to the ZYNQ that are specified at maximum ~1.9V are now supplied with 3.3V. This makes the ZYNQ run almost 10 degrees celsius hotter than it should, and will potentially damage the ZYNQ over a longer time.

What about ZZ9000 R-3?

If you have ZZ9000 R-3 from Batch 5 or later (to be shipped in August/September 2020), you don’t need to worry. The problem is already fixed.

Overview of ZZ9000 PCB layers

Copper fills are switched off in this view.

Zooming into connector U12 (top connector):

Close-up of pin 93 connected to 3V3 by mistake:

Fixing Methods

There are at least two known alternatives for disconnecting the 3V3 trace from pin 93 of U12.

The first step is always to unplug the ZYNQ module.

Then, either:

  1. Cut and remove a part of the trace with a box cutter or razor directly in front of the pin 93 of U12. This is indicated by “CUT” in the following graphic. You will need some sort of magnification lens or (cheap) microscope for this.
  2. Drill a hole with a ~1mm bit through the PCB at the location indicated by the X. The easiest way to find the right place without a template is to count the pins of U17 and U9 on the back. This is indicated by “DRILL” in the following graphic.

If you drilled the hole, make sure to remove any coppper debris in it. ZZ9000 is a four-layer board with internal copper fills. You want to make sure that 3V3 is not shorted to GND inside of your brand new hole. (Check the end of this document for hints on this).

Photo of where to Cut Trace (Method 1)

Thanks to Chucky!

Photos of Applied Hole (Method 2)

Technical Drawing of Trace/Hole Location

Top view of card:

How do I know it worked?

To confirm the successful fix, you need a multimeter in continuity mode / beeper and measure if 1V8 and 3V3 are still connected.

First, plug the ZYNQ module back in, or you won’t be able to check for the fix!

If the fix is applied, 1V8 and 3V3 rails should not be connected with the ZYNQ module plugged in (no beep).

An easy location to check are the south pins of C55 (3V3) and C53 (1V8):

Also, you should check that neither 3V3 nor 1V8 are now shorted to GND (for example by copper debris in the hole). You can do that by checking continuity across the pins of capacitors C53 and C55 each.

Overwhelmed With Repairs

I’ve said yes to far to many people in regards to accepting repairs of boards that are just beyond what I can do right now over the last several months. As a result things are way out of hand here. Unfortunately my full time jobs schedule has changed for the worse and hasn’t let me get things done that I wanted too or a lot of them are just in a state that I cant figure out issues for and are just beyond what I feel comfortable attempting to go any further with.

This sadly means I am going to be going through things that I will have to return as is. As many may know (oe if you didnt you do now) I dont like to charge for work that didnt result in a repair if I didnt spend any of my money on things I didnt have sent to me from donations or have on hand to do repair attempts. None of the returned work will cost anything other than return shipping. I sincerely apologize to those that have things I cant get working. Its just the nature of the way this hobby works some times. I will be doing recaps still and am getting through them. The mail system has made it very difficult for me to get parts in, but I have most of them and am working through the weekends to get the recaps done. If I contact you for the address to return please be understanding. I am only here on the weekends through the end of the year it looks like now, and have the potential to be stuck leaving the US again mid October for the rest of the year. I do not want peoples stuff stuch here if I have to leave again for that long.

Again, I am sorry if your board is one I cant get working or have to return as is, but I will be happy to try again or recommend someone that can look it over I truest and is known in our circle of trusted techs.