Jump to content

Photo

Myarc Geneve 9640 cards for sale/repair

Geneve Geneve 9640 Repair

114 replies to this topic

#101 RickyDean OFFLINE  

RickyDean

    Dragonstomper

  • 982 posts

Posted Mon Sep 17, 2018 11:54 AM

After I get the aspect ratio to come up properly on my images(does so In Photoshop, when I tell it to) I will have the cleaned up scans for the 4 layers of the Geneve PCB and the two for the HFDC ready to be released here to the wild. FYI, maybe tomorrow, if all goes well, here is a sample

Attached Files



#102 mizapf OFFLINE  

mizapf

    River Patroller

  • 3,396 posts
  • Location:Germany

Posted Mon Sep 17, 2018 4:51 PM

Is anyone making available the boot eprom chip for the Geneve that removes the swan and allows booting from mutliple devices?

 

 

It is definitely on my todo list, just to remind you.

 

(However, I also plan that my boot ROM has some Swan on the title screen, but maybe much smaller. I don't like boot EPROMs without the Swan. :-) )



#103 RickyDean OFFLINE  

RickyDean

    Dragonstomper

  • 982 posts

Posted Tue Sep 18, 2018 6:00 AM

Well, I finally got it down to fit on a single page from most image programs, So here, with the caveat that they probably not perfect, and though I tried to make sure I only removed clutter or enhanced areas that were not clear, are the resulting pictures. They ave been scaled down from the ones that I was originally editing and may have lost some detail (though they look pretty good to me. If you see something missing like the end of a trace, first before reporting it find Paul's originals on ftp.whtech.com and compare them. I know of at least two traces that didn't have an end point. Enjoy!!

Attached Files



#104 RickyDean OFFLINE  

RickyDean

    Dragonstomper

  • 982 posts

Posted Mon Oct 15, 2018 6:22 AM

Well I got my standard Geneve up and running again, a couple of weeks ago I had an issue with the card when I turned the P-box on of the swan coming up with squiggly lines running vertically up and down the screen. This weekend I replaced the vram chips and it worked for a few turn ons then started another strange activity, the screen with the swan was full of artifacts. I thought that I had blown those dram chips too, but decided first to remove the 9938 and swap it. Now this 9938 is the one I bought from China, when I first blew the card up, some months back. I had started working on the Geneve that I got from Insane Multitasker and used the old chip on there after making sure it was working on mine. I believe the video chip is faulty, and of the first vram chips, one of those tested bad. Don't know if the 9938 blew the ram or vice versa, but the ram was purchase from either Jameco or Mouser, so I don't think they were bad. The second set is fine and I can go into mdos and do thing:)

 

I would say at the moment, beware where you get you chips.



#105 InsaneMultitasker OFFLINE  

InsaneMultitasker

    River Patroller

  • Topic Starter
  • 2,270 posts

Posted Sun Oct 28, 2018 9:28 PM

For the past year or so, Swim and I have been talking about using switching regulators in place of the linear 7805s.  The primary benefits are reduced heat output and increased efficiency.  The suggestion originally came from ckoba,a past AtariAge member. 

 

  1. Before starting any work I did some baseline heat scans.  After 15 minutes, the three primary 5 volt, 1.5A regulators had reached a temperature of 170F degrees (approx 78C).  The memory chips directly above the regulators were being warmed to 120-140F (50-60C). 
  2. I first replaced all of the old electrolytic capacitors with newer, higher rated components.  A resistance check confirmed no shorts were introduced by my efforts.   I then removed the three primary 5v regulators and the associated input/output capacitors.
  3. Next I installed ceramic capacitors per the application notes.  This consisted of a 10uF capacitor on the input side and a  22uF capacitor on the output side. For this exercise, Swim recommended adding a 0.1uF ceramic capacitor in parallel with the 22uF on the output side.
  4. I reviewed my solder work, tested continuity again for any mistakes, checked for input/output orientation.
  5. Next - the smoke test.  I removed all cards from the PEB and inserted the Geneve.  I turned on the PEB and was greeted with the standard bootup swan.  Next, I added a floppy controller and proceeded to boot the OS.  I left the system running for an hour.  There were no visible signs that the switching regulators were causing any problems. 
  6. A heat scan showed the temperature of the regulators holding below 90F (32C).  I then scanned the chips and found that most were close to the same temperature with exception of the V9938. It was running at about 120F (48C).  I expect this is normal as I did not check its temp before the regulator change.

There are a few more things I want to update, such as removal of the 12v regulator (no need for it in my opinion) and testing whether or not the case will still close properly with the slightly higher regulator form factor. 

 

For a longer burn-in I may replace the heatwave Geneve with this modified Geneve.  Doing so will help me to confirm whether there is a noticeable difference in heat and operation between a PEB power supply and a PC ATX power supply (with 12v tied to the 5v line).  I suppose I should pull out my KillaWatt to compare power draw, to see if there is any difference in power use with the more efficient regulators.

 

Swim and I still need to do some more testing before feeling comfortable with this modification. However, early results are positive.  Here is a copy of the regulator data sheet. We'd be happy for anyone to look things over to make sure there aren't any "gotchas" that we haven't considered.   I've included pictures of the updated Geneve for reference.

 

Attached File  v78xx-1500.pdf   664.78KB   4 downloads
Attached File  IMG_1113.JPG   1.65MB   0 downloads

Attached File  IMG_1114.JPG   2.29MB   0 downloads

Attached File  IMG_1115.JPG   2.82MB   0 downloads



#106 dhe OFFLINE  

dhe

    Space Invader

  • 21 posts

Posted Mon Oct 29, 2018 8:08 AM

Fascinating stuff!

Great job Tim and Richard for figuring out this mod, it's pretty easy to see the heat damage that has already occurred...

What's the 12V regulator for?

Other things I don't know, whats the voltage on RGB signals?

Does anyone on here remember which chips on the Geneve need to be changed for use with Ron Walters Memex card?

    I vaguely remember some chips needed to be swapped from LS to HCT?

   This page offers a pretty good explanation of logic families and incompatibilities....

     https://www.avrfreak...s-ls-hc-hct-etc

 

d.



#107 InsaneMultitasker OFFLINE  

InsaneMultitasker

    River Patroller

  • Topic Starter
  • 2,270 posts

Posted Mon Oct 29, 2018 1:26 PM


What's the 12V regulator for?

The 12v regulator provides power to the video connector.  It's dangerous having it out there, especially with some of the RCA to 5-pin DIN cables people use for composite video.  I think it also powers one of the chips used for composite video so before I do any further surgery I still need to trace the connections.  A jumper to enable/disable the 12v output on the connector would have been a nice "feature".   (I disabled the 12v output on my TI for safety reasons).



#108 InsaneMultitasker OFFLINE  

InsaneMultitasker

    River Patroller

  • Topic Starter
  • 2,270 posts

Posted Tue Oct 30, 2018 10:04 PM

Confirmed that the new regulators work well with the Myarc case. They will no work as-is with a TI or corcomp case, as the body of the regulator partially covers the threaded holes used to keep the case together.  It might be possible to bend the leads a bit to provide sufficient clearance.  Some different varieties of dc-to-dc switching regulator may provide the 'traditional' through-hole.



#109 InsaneMultitasker OFFLINE  

InsaneMultitasker

    River Patroller

  • Topic Starter
  • 2,270 posts

Posted Fri Nov 2, 2018 4:44 PM

I had a chance to take Heatwave offline this afternoon.  I have temporarily swapped the Heatwave BBS Geneve with this newly updated card.  I'll let it run for a few days to see how well it operates. I hope to find time to refresh the BBS card while it is out of service. :)

 

On a related note:  although the Myarc cases look like plastic they are conductive.  With the test leads in close proximity, I registered 1.5K; at a distance of 1 inch it was aproximately 3.4K.  I suspect case composition varies. A few of the dc-to-dc converter leads needed to be clipped to avoid contact.


Edited by InsaneMultitasker, Fri Nov 2, 2018 4:46 PM.


#110 InsaneMultitasker OFFLINE  

InsaneMultitasker

    River Patroller

  • Topic Starter
  • 2,270 posts

Posted Fri Nov 2, 2018 11:41 PM

The Geneve schematic incorrectly depicts u55 in two places.  I seem to recall this was brought up some time ago.  Looks like my repair notes propagated this error.  Such is life.

  • The 12v regulator (u55) supplies voltage to the MC1733CP video amplifier and the video port.
  • The 5v regulator (u56) supplies voltage to the V9938.  It may be appropriate to refresh this regulator or replace it with a more efficient dc-to-dc part as wileyc mentions in another thread. 
  • I somehow missed replacing the capacitors associated with these two regulators when I changed the caps.  :dunce:

The modified Geneve has been running for 8 hours with no issues.  I'll let it run for the weekend. 



#111 Opry99er ONLINE  

Opry99er

    Quadrunner

  • 9,921 posts
  • Location:Hustisford, WI

Posted Fri Nov 2, 2018 11:49 PM

AWESOME!!!



#112 InsaneMultitasker OFFLINE  

InsaneMultitasker

    River Patroller

  • Topic Starter
  • 2,270 posts

Posted Fri Nov 9, 2018 1:27 PM

I had a chance to take Heatwave offline this afternoon.  I have temporarily swapped the Heatwave BBS Geneve with this newly updated card.  I'll let it run for a few days to see how well it operates. I hope to find time to refresh the BBS card while it is out of service. :)

 

Been running a week without any problems.  I may take the system offline this weekend to swap cards and do some more work with the new regs. 



#113 InsaneMultitasker OFFLINE  

InsaneMultitasker

    River Patroller

  • Topic Starter
  • 2,270 posts

Posted Sun Nov 11, 2018 2:26 PM

too cold out in the garage to do any work on the Geneve. I did take the system down briefly to replace the boot EPROM with Gazoo's version 1.00.  I also completed quick heat scan.  The two dc-to-dc converters on the LED side of the board were running between 95-100F.  The converter on the V9938 side was running just under 110F.  The 9938 was running at 135F and most other chips were in the 100-120F range.  For reference, this is with +12v supplied to the 5v rail via a PC power supply.



#114 RickyDean OFFLINE  

RickyDean

    Dragonstomper

  • 982 posts

Posted Mon Nov 12, 2018 7:11 AM

Are you getting 5 volts, I purchased some 5 voilt Traco units and they only output about 4.80 volts, would not fire off my CF7+ so I had to go back to a 5 volt regulator.



#115 InsaneMultitasker OFFLINE  

InsaneMultitasker

    River Patroller

  • Topic Starter
  • 2,270 posts

Posted Mon Nov 12, 2018 11:13 AM

Hmmm, good question.  I didn't bother to check the outputs.  I'll find my extender card and measure them for you the next time I work on the Geneve.







Also tagged with one or more of these keywords: Geneve, Geneve 9640, Repair

0 user(s) are browsing this forum

0 members, 0 guests, 0 anonymous users