Building a Vintage DRAM Tester & Testing AliExpress FAKE(?) 4116 and 4264 DRAMs?

[@MarkFixesStuff]

What do you think of the 4116/4164 DRAM tester? Is it something you might use yourself? I was confused with the outcome of the AliExpress chip testing. They are clearly overprinted! What can it all mean?

[@GORF_EMPIRE]

I would if I did not already have a TL866 burner which I believe tests all sorts of RAM's and even 74 and 40 series logic chips. Great little project for someone in need of those specific chips for sure.

[@kattan2006]

Yes for sure. I fix Spectrums as hobby mostly and this device is indeed very useful.

[@GORF_EMPIRE]

@@kattan2006 I can see how it would be useful for specific machines like those you repair.

[@jeroensmaal]

@@GORF_EMPIRE The TL866 does not test DRAMs.

[@GORF_EMPIRE]

@@jeroensmaal Ah... looks like you are correct..... SRAMS only it seems. Well then. Looks like I need this kit then! xD

[@RMCRetro]

Definitely a tool for The Cave Mark, it might go missing when you next visit

[@MarkFixesStuff]

Stop nicking my stuff and stay up your end of the cave!

[@tailzer42]

I’ve made a version that just runs off the usb 5v, more than welcome to a pcb to make up (either of you but Mark already has one 😂)

[@Codersys]

Maybe I`ll send you one for your birthday ;-) (shame I don`t know when that is!!) - o well, you`ll have to rob Marks one then ;-)

[@chriscrossan8034]

I have no DRAM chips and I have no need of any. Doesn't stop me wanting to build that tester though! Cool project.

[@Codersys]

Love it Chris 🤣🤣

[@JimLeonard]

Very clear and thorough demonstration. I look forward to your future work.

[@MarkFixesStuff]

Thank you very much Jim!

[@temporarilyoffline]

For Hand Soldering SMDs stuff, I found a nice pair of hold-close tweezers that will hold the part and then I pre-tin tin the pads, hold in place and tack down one side. The only wrong way is one that doesn't work though. This looks like a fun kit to build.

[@MarkFixesStuff]

I used to pre tin the pads myself, but found with flux and the iron “blobbed” I could get the components flatter to the PCB. It really is a question of taste as you say. I can’t use the hold close tweezers. I think I need to grip them to keep my hand steady!

[@Codersys]

That is how I do them, a small blob on one pad. Reheat and slide in SMD, flatten SMD to board and solder other side of SMD in-place. I use a LCD magnifier screen setup too. But like you say, lots of different ways to do same job. :-)

[@Colin_Ames]

It looks like a great tool for those who need it. It’s not something I have a use for but it’s good to know it exists.

[@Dev_olution]

Great video Mark, appreciate the soldering tips. Thanks

[@MarkFixesStuff]

Cheers Dev and thank you also for your important support!!

[@peddersoldchap]

Hi Mark! Could you do a video like this one but with an open source tester? Maybe one that tests the 4416 (for the amazing Timex TC2048). Plox?

[@MarkFixesStuff]

Good suggestion but I’m financially b******** for the foreseeable future. I’ve got a lot of things in the go!

[@grantm902]

i don't like the convention of having the square pad be the cathode, as it's in contradiction to ICs where pin 1 is denoted by a square.

[@Edman_79]

Mark, thanks! I always learn something new here.

[@MarkFixesStuff]

Happy to help Edman!

[@kattan2006]

You always surprise me with things I didn't know they existed. Very interesting video, thank you

[@MarkFixesStuff]

So nice of you to say so! Thanks Ali!

[@diegocipriani]

I love the smell of flux in the morning... smells like soldering

[@Verightess]

I'd have to fix that, It would drive me crazy..

[@MarkFixesStuff]

It's all ashes now anyway.

[@Verightess]

@@MarkFixesStuff I know, Sorry that happened. Did you ever figure out what started the fire?

[@ToddsNerdCave]

I had no idea anyone produced one of these. Might need to pick one up.

[@MarkFixesStuff]

It’s such a time saver Todd.

[@Codersys]

Well - now you do know Todd ;-) Cheers

[@ToddsNerdCave]

@@Codersys Indeed I do!

[@tejp5101]

Hi Mark, I can't find any link for this device. Is it still being made? A google serach doesn't reveal anything.

[@MarkFixesStuff]

Hi. Stephen doesn't seem to make these any more, but if you search ebay you can find alternatives. I've used one of these www.ebay.co.uk/itm/115545495551

[@KJohansson]

Looks like a neat kit, gonna get me one of those. But I thought the rule when soldering was the same as with mixing drinks, always start with the cheapest components incase something goes sideways and one have to start over..

[@MarkFixesStuff]

For me I don’t have that rule. It depends on your level of confidence and experience I guess.

[@MarkFixesStuff]

And I never throw a drink away Hahah

[@pseydtonne]

Agreed. I was weirded out to see the pins for the Arduino board soldered to the main board first. I would have: 1) put the pins into the main board for alignment; 2) soldered the Arduino board to those pins; 3) taken the Arduino board back out to solder the programmer pins; 4) left the completed Arduino board out to test it; 5) dealt with the tiny parts; 6) soldered the Arduino to the main board. Then again, I'm not a flashy demonstrator. I get lost in tangents, such as this one...

[@winstonsmith478]

Tests for defective/dead, can't test for rated speed compliance. Perhaps an M0 or M4-based Arduino module with their higher clock speeds could manage that?

[@MarkFixesStuff]

Once I know the chip type is actually correct I can safely test them in a machine like the spectrum which will run a full diag.

[@davidretrogamesplayedbadly3533]

Great build mate, although I reckon the gummy bears are getting a bit too big for there boots, have they started making demands?

[@MarkFixesStuff]

Not yet but I keep finding trip hazards around my work area...

[@Synthpeter]

Moderately triggered by the brief red Fail LED blink at 19:36 during the test and 20:30

[@MarkFixesStuff]

It blinks between the four test patterns. The final LED is the decider!

[@ZaPpaul]

I've purchased lots of ram chips from Aliexpress 100+ with very few failures. I do tend to check the retailers feedback first though and always go with good reviews.

[@MarkFixesStuff]

Me too. The strange pattern of sanding made me wonder though!

[@ZaPpaul]

@@MarkFixesStuff I think they just try to make them look all the same. A bunch of different brands/years stamps makes them look second hand. Which of course they are :)

[@MarkFixesStuff]

@@ZaPpaul Yes! The mad thing is that are about 45 UK pence each including shipping, I'm quite happy with pulls, and would be happier seeing the real maker and speed.

[@pianoplayer9203]

Great video .Thank you so much

[@MarkFixesStuff]

You are welcome!

[@TzOk]

A Few days ago I've built this tester: github.com/andremiller/arduino-dram-tester but added a 128x32 OLED display instead of using PC serial terminal. I didn't bother making 4116 version, as 4164 can be easily adapted as 4116 replacement, and I have only 4164 on stock. Your DRAMs are rather working, but it is clearly visible on video, that they were "sanded" (or in this case machine honed) and re-engraved.

[@MarkFixesStuff]

Yeah. I think they want to pretend that old pulls are actually new stock.

[@RonHelton]

That's a great tester.

[@Codersys]

Thanks 🤗

[@MarkFixesStuff]

Glad you think so! Stephen did a great job!

[@chrisrobson8540]

As I was always taught the 6 p's....proper preparation prevents piss poor performance

[@SimonEllwood]

Nice video, you need some Lindstrom side cutters however. Great tools well worth the money ;)

[@MarkFixesStuff]

I’ve got about seven pairs of these cheapies. I’ll look to upgrade to the ones you suggest. Thank you!

[@SimonEllwood]

@@MarkFixesStuff I just checked the model number of my 20+ year old cutters SANDVIK 8150. Only £32 quid on one site (not tried).

[@MarkFixesStuff]

@@SimonEllwood the "Lindstrom 8150 112.5mm 80 Series Cutters (Oval Head) with Micro-Bevel Cut"? They look lovely. I'm afraid I'm really up against it financially right now due to the pandemic and losing my work, but should things turn around these will be on my list for sure. Thanks so much for finding me the info and posting it. I really do appreciate it :)

[@strule]

could you please provide me with the part number of d1 and d2? I'm working in a project and think they will fit nicely on it

[@MarkFixesStuff]

They're just standard 1n4001 diodes :)

[@strule]

@@MarkFixesStuff thank you

[@PebblesChan]

The tester is overly simplistic. I would be good if it had a small LCD screen so it could indicate the maximum refresh times and cycles required, whether the DRAM supports CAS before RAS, page mode and presence of internal refresh counter. From this additional info you can work out the probable manufacturer.

[@MarkFixesStuff]

Nice idea! Will you make a version? I can review it for you!

[@PebblesChan]

I use my Australian Microbee computer to test my DRAM ICs. Although it does not use hidden refresh cycles or page mode, it is designed to work with both 2ms (128 cycle) and 4ms (256 cycle) 4164, 41256 and 1mbit DRAMs. Even when populated with bad DRAMs the unit powers up from ROM to run a self test. The beauty of its Z80 CPU means that it can run programs without any RAM by just using its inbuilt registers. The microbee also has 4K static RAM for its video subsystem which can be used as stack, scratch storage and display independent of its system RAM.

[@basvanharen2904]

I need one!!!😁 I realy dont like using all that flux for through hole components (well actualy it doesnt seem too much watching your video😅). I'm using solder with a leaded core which make the solder flow enough imho. But I gues thats a preference.

[@Mark1024MAK]

You mean you are using solder with a core (or five) of flux?

[@MarkFixesStuff]

I like to overdo it fo the visuals to be honest. It doesn’t really hurt and I hope it informs people as to the science of soldering.

[@basvanharen2904]

@@MarkFixesStuff Agree👍🏻 thx for the reply!

[@shadowtheimpure]

Personally, I would socket the arduino but that's just my preference.

[@MarkFixesStuff]

Me too if it was my own project, but I don’t have the sketch anyway (and a clone Nano is under three pounds these days.)

[@shadowtheimpure]

@@MarkFixesStuff The socketing would be to replace the Arduino should it decide that it no longer wants to participate.

[@MarkFixesStuff]

@@shadowtheimpure good thinking.

[@markb4071]

quite like the look of the board holder, Mark. Where did you get it from please

[@MarkFixesStuff]

CPC Farnell own brand mate

[@GORF_EMPIRE]

Another fine job well done!

[@MarkFixesStuff]

Thanks Gorf!

[@GORF_EMPIRE]

@@MarkFixesStuff Not at all! thank you for entertaining videos!

[@neilgillmore]

Great job and an awesome tool.....

[@MarkFixesStuff]

Thanks mate!

[@stanburton6224]

I cannot find this project on ebay at all.

[@MarkFixesStuff]

Here you go Stan: www.ebay.co.uk/itm/D-I-Y-KIT-4116-4164-DRAM-TESTER-ZX-Spectrum-48k-128k-C64-more/154385445503?hash=item23f216f27f:g:8y4AAOSwOQpfovle

[@Codersys]

@@MarkFixesStuff thanks Mark. Stan, if it drops off its because I sold out.. just keep checking back every now and again, they soon go back on ;-)

[@Rorschach1024]

@@Codersys the problem is I'm in the US, not the UK, and when I go to the UK site it says it cannot be posted to the US. The item is not listed on the US site, and my US credentials don't work on the UK site< and it demands a UK address to set up an account.... well see, that's a problem....

[@chrisg6597]

I'm not sure I like the power being on the test sockets when inserting the ram chips. It could be possible (especially on the multi rail 4116's) to start back biasing pins or applying over/under voltage to the pins on either the ram chips or the Nano when the chips are inserted, especially if GND is the last pin to connect.

[@chriscrossan8034]

Forgot to ask, what make are the tweezers and where can I buy them?

[@MarkFixesStuff]

Ah sorry Chris! Missed this. I just got this set from Amazon - amzn.to/3baF6d9 - Really good and fine points!

[@chriscrossan8034]

@@MarkFixesStuff Thanks!

[@gordonlawrence1448]

I could tell they were fake by looking at them. TI have used a date code on everything since the 1940's It has always been the same format too. IE week then year in 4 digits. The only thing that has changed is the addition of a letter for the factory and the change from paint to laser etch. 1115 is not a valid date code for the 4116. They were obsolete in the early 80's or mid 80's at the latest. Those markings looked laser etched (more like engraved) then paint filled. TI has never done this (I cant think of a manufacturer that has).

[@MarkFixesStuff]

Yeah... Plus they are all identical AND the text is in different places, skewed etc. It's a whole lot of bother for a very cheap item. Thanks for the in depth info too Gordon, I really appreciate it!

[@TheEPROM9]

Ineed one of these.

[@MarkFixesStuff]

Get one Si!

[@dant5464]

I visited the URL on the label of the isopropanol bottle... looks like someone else took ownership of the domain since you purchased it? 😄

[@MarkFixesStuff]

Can’t say I was curious enough to do that!! Is it porn?

[@dant5464]

@@MarkFixesStuff "Skin safe body adhesive" and body tape for carefully covering bits up, so maybe porn-adjacent? :p Odd to see on a bottle of stuff you should keep off your skin. I'm guessing you ordered it from eBay or similar and that turned up.

[@MarkFixesStuff]

@@dant5464 yes. A pack of two bottles, and it was about a month into the pandemic so they cost a bomb if you could even find them.

[@legin3753]

Hi I'm new to soldering is there any kits for beginners i could buy to get better thanks

[@MarkFixesStuff]

Really the best thing to do is get a temperature controlled iron, some good solder, some flux and a smallbottlle of IPA then solder some various hobby kits. People might tell you to practice on old motherboards, but that's not good experience in my book. They are factory soldered and can be a nightmare. Try some Velleman kits.

[@legin3753]

@@MarkFixesStuff thanks for reply man i actually have ksger soldering iron and duratool desolder same as rmc watched his review on it have everything apart from a decent kit to practice ha i will look up the velleman kits thanks so much

[@Omegaman1969]

I wish someone would make a 2107 tester

[@johnharmer394]

Looks great. Pity the eBay seller doesnt ship to Australia :-(

[@MarkFixesStuff]

Yeah, we've got a few customs and border issues right now...

[@onkelnb]

Who makes a board full of holes and then uses SMD resistors?

[@MarkFixesStuff]

I think it was so the board sits flat, and I don't think it was meant to be a kit until the maker got a lot of requests. Apparently the next version will be THT?

[@Codersys]

@@MarkFixesStuff possibly multichoice version, with both Resistor types to choose from.

[@electronash]

Allo. Enjoyed the vid, mate. ;)

[@MarkFixesStuff]

Thank you Lord oZone!

[@tonelander9534]

Have you been speaking to my wife ? How did you know I use tweezers to place my parts ?

[@MarkFixesStuff]

I’m on your Onlyfans

[@kokodin5895]

yey polish flux

[@MarkFixesStuff]

The BEST I have ever used!

[@billmilligan1705]

Don't you think that's a waste of good Indian pale ale (IPA) ?

[@MarkFixesStuff]

I would never do that! I'm calling my lawyer!

[@IvanIgnath]

This was built in wrong order! Always start with smallest parts... smds, lying tht, standing tht, connectors, subassemblies (arduino)

[@mariushmedias]

I see absolutely no reason why those surface mounted resistors had to be used. There's plenty of space on the circuit board to route the traces a bit to the side outside the chip footprint and place regular resistors there. Looks like designer got lazy. Also a bit weird the power stuff ... the barrel jack silksreen says +9v ... the 7660 inverts to around -8..-7v and then the 7905 makes -5v so I guess that's fine, but where's the +12v coming from? Or are they using the 7660 in some non standard configuration, like maybe voltage doubler and then regulate down to +12v?

[@Codersys]

Hi - You guessed it right, the 7660 can be used as a voltage negator (-8v) or a voltage doubler (about +16-18v), OR as both at same time in this case ;-)

[@MarkFixesStuff]

Nice sleuthing MaruishMedias!