SIMMS - Parity or not - Opinions please

[rubber_jonnie]

It sounds like the "usual ignorance " of people..

I tested 100s of Simms a few years ago. Some I had for years , others brought more recently. I did post the info before can't find either..

Anyway, I don't remember exactly, but the first 40 sets all worked fine, but the 40 sets I found later did not. So I removed all the parity chips and they was fine then.

It really depends on brands of dram. Some don't care about floating lines, others do and cause the faults shown in my video. It is long known you shouldn't have floating signals, its like electronics 101. But people being people, don't care and as it works , won't listen. Who's to say the odd crash they could get now and then isnt down to parity Simms... They just wouldn't know..

Then they will get smart and run ram test to prove the point that the ONE set they have works fine..so falsely concluded every simm in the world I is fine... But its pot luck..

Even more complicated is even if RAM passes all day, it doesn't mean it is stable when ROM is being accessed.. Look at my video, doing ram test fails and corrupts the screen, then on desktop its fine..

Try and explain to people all this people.. 99% can't get past that ram can still cause problems and still pass RAM test fine all day.. Then they start to flame you so you go setup your own forum to get away from such people.. :lol: :roll:

As I said in the moderators forum, its not our job to teach people basic electronics , help people if they are willing to learn and listen,yes. otherwise hit the block button and just let um get on with it all..

EDIT:
The ram test software itself may or may not be reliable .. I will never forget when I tried memtest87 on my PC years ago.. Said RAM was fine.. I wasn't convinced.. I went back to memtest86 and it found faults right away..

We need a 'like' function for posts like these :)

[exxos]

FB is... 'stupid'. The same question over and over. Hard to search and know how much info already exist there.

Totally agree. Problem as well is so much bad info out there that people accept it as facts :roll: again a reason I started this forum to post real proper info and facts.

[beel1]

I have seen non parity 3 chips SIMMS, there were 2 3 bit and one 2 bit chips on there, which surprised me a little, not that I'm saying this is the rule, more like the exception.

Yours is a case in point too, it works just fine for you, yet both my STEs fail in a similar manner to the video exxos posted with parity SIMMS. Trouble is there is so much 30 pin SIMM stock out there, it is going to be pot luck if you happen to find a set with parity, as you have that works. And your experience proves you can :)

Mine are "Topless" 1MB*9 just like this (60 or 70ns, I can't remember):

57-2.jpg

[rubber_jonnie]

Mine are "Topless" 1MB*9 just like this (60 or 70ns, I can't remember):

57-2.jpg

I seem to recall that brand actually, though I don't have any in my Big Bag 'O RAM. I think I see a 60ns printed just above the1/22 section of the date.

I recently fitted a Marpet adapter to a Mega ST and dropped 4MB in, the first lot I found being parity. Didn't work, as soon as I put non parity in it was fine and dandy.

[exxos]

As a side note.. 60ns is very hit and miss to work.. You have to change the mad resistors etc to more like 33R to get 60ns to be stable. I used even 50ns with 33R.

[beel1]

I think I see a 60ns printed just above the1/22 section of the date.

This is a picture I found on the internet, it's not the one inside my Atari :D

[rubber_jonnie]

I think I see a 60ns printed just above the1/22 section of the date.

This is a picture I found on the internet, it's not the one inside my Atari :D

Ahh, I see :)