Another run of Disk RAM drive boards

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Another run of Disk RAM drive boards

Postby vbriel » Feb Tue 28, 2012 10:47 pm

After a lot of requests, I've decided to do another run of 88-DSK-RAM boards. The only real issue we've seen is the occasional byte change on the RAM drive during power on/off at random times. We're working on that but I feel safe to do another run. Keep your RAM drive backed up onto the SD card and you will be ok. Don't miss out, I'm only doing 20 more again. See the post above on the beta run for more info or order from here:

http://www.brielcomputers.com/88dskram.html

Vince
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Re: Another run of Disk RAM drive boards

Postby vbriel » Mar Mon 12, 2012 2:18 pm

There are 10 boards remaining.
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Re: Another run of Disk RAM drive boards

Postby vbriel » Mar Thu 29, 2012 12:37 pm

6 kits remaining
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Re: Another run of Disk RAM drive boards

Postby menkelis » Mar Fri 30, 2012 1:37 pm

Has the memory corruption issue been resolved?
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Re: Another run of Disk RAM drive boards

Postby vbriel » Apr Wed 04, 2012 2:36 pm

we know when it is happening, just don't have the solution yet. 4 kits remaining. Kits will start shipping later this week!

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Re: Another run of Disk RAM drive boards

Postby jgalinat » Apr Wed 04, 2012 8:39 pm

Hi Vince,
Did anyone with the ram drive board install the fix you mentioned below and get back to you with the results?

"My solution is not tested yet but maybe some of you soldering masters would like to give this a go. On pin 29 of the RAM chip below C6 capacitor, solder a resistor (3-10K range should work). Solder the other side to C6 positive pin (closer to the other RAM chip). This will pull the WRITE pin high and force it to be pulled low when a write is being attempted. "

Jeff
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Re: Another run of Disk RAM drive boards

Postby vbriel » Apr Wed 04, 2012 9:41 pm

I can't remember for sure, but I think so and it didn't fix. The common thinking is the ATMEGA is doing strange things on power off causing the RAM byte to change. An isolation circuit is probably required. Pulling the /WR high will help I think but if the ATMEGA AVR is doing strange signals on power off, it can overide the pullup resistor.

I believe I did a test where I kept the ATMEGA powered up all time with the RAM on the battery circuit and that made the problem go away but the power draw was HUGE! That hard part is that it doesn't happen all the time, just every once in a while so it is hard to track down.

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Re: Another run of Disk RAM drive boards

Postby jgalinat » Apr Sun 15, 2012 5:21 pm

Hi Vince,
Per your April 4th post, have the 2nd run of the RAM disk kits started shipping yet?
Thanks,
Jeff
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Re: Another run of Disk RAM drive boards

Postby vbriel » Apr Sun 15, 2012 9:19 pm

Well, parts are in and I will be shipping starting Monday the 16th! Yeah! You will get an email as they ship.

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Re: Another run of Disk RAM drive boards

Postby SteKos » Apr Mon 16, 2012 11:52 am

Hi Vince,

Are there any boards left in the 2nd run of 20?

Thx.
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Re: Another run of Disk RAM drive boards

Postby vbriel » Apr Mon 16, 2012 5:07 pm

I have about 3 left guys!
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Re: Another run of Disk RAM drive boards

Postby jgalinat » Apr Mon 16, 2012 5:14 pm

Vince,
Great! (on the shipping progress for the RAM drive kits). I'm getting excited already! Thanks for all your efforts (and the other folks who helped out debugging & troubleshooting) in putting out a quality product.
Jeff
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Re: Another run of Disk RAM drive boards

Postby SteKos » Apr Mon 16, 2012 5:19 pm

Make that 2 left. My order is in.

Sorry, I ordered the assembled model. My eye-sight sucks for close up work.
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Re: Another run of Disk RAM drive boards

Postby vbriel » Apr Tue 17, 2012 11:27 am

And what makes you think mine is any better :P
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Re: Another run of Disk RAM drive boards

Postby SteKos » Apr Tue 17, 2012 2:54 pm

If you can pre-build the KIM kits, the RAM disk board for the Altair Micro should be a piece of cake.
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