Arduino 4116 Dram tester with an extrenal help.

For experts to discuss very technical stuff and newbies to ask why the Spectrum they bought off ebay doesn't work.
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Muttley Black
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Arduino 4116 Dram tester with an extrenal help.

Post by Muttley Black »

Hello everybody!

I made an Arduino 4116 dram tester, to help me check the ZX Spectrum (lower Ram) IC's.

This Project based on 4164/41256 Arduino Tester that you can find it here. If you build your self's the exact project, you can easily test the (Upper Ram) IC's. But what about the lower ram ic's?

To be able to test 4116 dram ic's, just build one more Arduino tester (in case you want both of them), with some modifications on the original schematic.
Don't need to change the Arduino code, as the 4116 / 4164 are about the same, except of course the voltages. So you just need to put -5 volt at pin (1), +12 volt to pin (8) and +5 volt to pin (9) of ic.
You can do this simple, with the help of "positive negative output power supply".


4116 / 4164 Voltages:

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Some photos of my Arduino 4116 Dram tester:


ImageImageImage


A sort video with Arduino 4116 Dram tester in progress:

[media]https://www.youtube.com/watch?v=LPavFz61ifM&t=8s[/media]


Happy to be here, have fun!
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1024MAK
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Re: Arduino 4116 Dram tester with an extrenal help.

Post by 1024MAK »

Looks good, great work 👍 :D 👏

Note that some 32k X 1 bit DRAM chips (including all used in ZX Spectrum 48k / Plus computers) are actually 64k x 1 bit (4164 or equivalent) chips where at least half of the memory cell matrix worked correctly when tested by the manufacturer (the rest may not have passed all the tests). And as such, these are all 16 pin DIP / DIL packages that are 5V only parts.

The 18 pin 32k X 1 bit DRAM chips that require the three supply rails plus a 0V/ground are rather uncommon.

The second thing that may be worth considering, is for the 4116 (or equivalent) chips, one failure mode is where the silicon becomes degraded or becomes damaged, such that either the +12V or the -5V can leak via internal short circuits out to address, control or data pins.

So rather than directly connecting to the Arduino I/O pins, use 150 ohm or 220 ohm resistors between the Arduino and the DRAM address, control and data pins. This will give the Arduino some protection.

Mark
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Muttley Black
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Re: Arduino 4116 Dram tester with an extrenal help.

Post by Muttley Black »

Thank you!

Also thank you for your nice info you posted about protection.

I did the Arduino 4116 dram tester, to be able to check and repair my one and only ZX Spectrum issue two board back then. When I've had only one unit. Now that i have more than one and always i am interested to buy faulty ZX Spectrum's for practice my repair skills, i made the issue two my testing board. I put sockets in all IC's so i can swap and test IC's from other boards.


Image


For the story, to be able to check Nec and hitachi Rom's, i did the choice to be switchable.


ImageImageImage


And of course i moved the ztx313 “spider mod” of CPU in solder side, to be able to swap CPU's.


Image
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Muttley Black
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Re: Arduino 4116 Dram tester with an extrenal help.

Post by Muttley Black »

Mark, only address pins want resistors? Pins 5,6,7,10,11,12 and 13?
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1024MAK
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Re: Arduino 4116 Dram tester with an extrenal help.

Post by 1024MAK »

ALL pins on the 4116 except for pins 1, 8, 9 and 16.

Mark
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Re: Arduino 4116 Dram tester with an extrenal help.

Post by Hyuma »

Hey guys, I've tried the DRAM tester with 3 different faulty 4264 RAM. During the test, the green led is blinking and sometimes also the red blink, but at the end, the green one is on and on Serial monitor I've DRAM OK message. This is strange because RAM is faulty and it must be the Red led On. Any idea why happens this?
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Re: Arduino 4116 Dram tester with an extrenal help.

Post by herbert_s »

Hi,

found a really nice memory tester project here:
https://8bit-museum.de/sonstiges/hardwa ... hertester/
There is a manual available and some videos. Looks promising...

Marcus
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Muttley Black
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Re: Arduino 4116 Dram tester with an extrenal help.

Post by Muttley Black »

My first attempt building an Arduino 4116 tester in one board. I put protection too. Still in testing mode.


Image
Firefox

Re: Arduino 4116 Dram tester with an extrenal help.

Post by Firefox »

Small question: how do the electrons get into the board? :?
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Re: Arduino 4116 Dram tester with an extrenal help.

Post by Muttley Black »

Hello sure, but I am not sure if I understand the question. If you mean how this board get power to work the answer is, through the Arduino.

Have in mind that the board you looking it is not in final design. This is the very early design to do my test’s. After that I do some modifications.

When all seems to work properly I will release the Kicad schematic and the Gerber files for those want to build it.
Firefox

Re: Arduino 4116 Dram tester with an extrenal help.

Post by Firefox »

Muttley Black wrote: Sun Apr 26, 2020 3:24 am Hello sure, but I am not sure if I understand the question. If you mean how this board get power to work the answer is, through the Arduino.
That is what I meant! Thankyou! :)
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Muttley Black
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Re: Arduino 4116 Dram tester with an extrenal help.

Post by Muttley Black »

Hello all.

This is the final design for my Arduino 4116 Dynamic Ram tester. At least for this version. I can’t wait for my first prototype boards to came and start the testing. After that and if all go smoothly i start the printing for this version. 7~12 dc volt barrel jack fitted in this version to power up the board from external power supply and not only through the Arduino usb, plus i add some protection for the Arduino

Image
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1024MAK
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Re: Arduino 4116 Dram tester with an extrenal help.

Post by 1024MAK »

Looking good 8-)

Mark
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Looking forward to summer later in the year.
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Muttley Black
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Re: Arduino 4116 Dram tester with an extrenal help.

Post by Muttley Black »

Thank you Mark.
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Re: Arduino 4116 Dram tester with an extrenal help.

Post by Muttley Black »

The prototype pcb's has not yet arrived, but i decided to do some changes for the final version. I reduced the board size. From 12cm x 11cm it was, it came to be a little less than 10cm x 10cm. This is because the cost of its construction is significantly reduced, but also for reasons of space saving.

Image
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Muttley Black
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Re: Arduino 4116 Dram tester with an extrenal help.

Post by Muttley Black »

Almost done! :D

I am waiting some more components to arrive.

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Re: Arduino 4116 Dram tester with an extrenal help.

Post by herbert_s »

herbert_s wrote: Sat Mar 07, 2020 5:56 pm found a really nice memory tester project here:
https://8bit-museum.de/sonstiges/hardwa ... hertester/
There is a manual available and some videos. Looks promising...
The guy has updated the hardware
https://8bit-museum.de/sonstiges/hardwa ... hiptester/
Seems to be a really great tester
https://forum.classic-computing.de/foru ... museum-de/
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Re: Arduino 4116 Dram tester with an extrenal help.

Post by Muttley Black »

Waiting the damn inductors to arrive.... :roll:

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Re: Arduino 4116 Dram tester with an extrenal help.

Post by Muttley Black »

There was some errors in the prototype PCB. I did some emergency cable jumpers to solve the problem. Now it is ready and 100% in working order. Sadly I need to order some new pcb’s for the final test. This tester work also with 5 volts, through the Arduino usb plug. This future make it a bit portable with a power bank.


[media]https://vimeo.com/454361906[/media]
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Re: Arduino 4116 Dram tester with an extrenal help.

Post by 1024MAK »

Ahh, bodge/mod wires are normal for a first version. So don’t worry about it :D

It’s working, that’s the cool bit 8-)

Mark
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“There are four lights!”
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb :dance
Looking forward to summer later in the year.
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Re: Arduino 4116 Dram tester with an extrenal help.

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