The Startek DT-90 Project.

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Muttley Black
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The Startek DT-90 Project.

Post by Muttley Black »

There is few days now that I am trying to recreate the pcb from the Startek DT-90 dram tester. I always wanted to start that project and this time has come.

It is not so easy but I want very much to give a try.

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Here are the pcb prints that I take from the magazine:

Image

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And here is the pcb mask:

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Here is my work so far:


Image


Any suggestions are more than welcome.

Thanks.
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RMartins
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Re: The Startek DT-90 Project.

Post by RMartins »

Still some work to do on that lower half.

Do you have the parts list ?
Could be an interesting project to build.

NOTE: On DIP chips, usually only pin 1 as a square footprint, the others should be all round.

Are you mimicking the board by hand ?
I'm asking, because I don't see the usual lines, representing the connected signals that are not yet routed.

It would probably be simpler for you to create the schematic or netlist first, and go from there.
I hope you are using some form of CAD program like KiCad, Eagle or similar.

To created the original box, you will need a laser router, to burn those lines into an Alumminium box, pre-painted or anodized in black.

Is there any article about how it functions, i.e. tests the RAM, because it seems to be only electronic/digital, without any CPU.
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Muttley Black
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Re: The Startek DT-90 Project.

Post by Muttley Black »

Hello RMartins.

First i have to say that i am not well experience making pcb's. I do every project first for my own pleasure and practise.

The part list yes, It is available (look at the end of this post). About the square footprint that have to be at the pin 1 and only, i mess it around accidentally. It is an easy fix don't worry about that. I try the mimicking by hand method cause i wont the final result to be almost as the original. Trying that by create the schematic first on kicad and then rooting the pcb is hard for me.

Here is the magazine on pdf.

https://www.dropbox.com/s/m1yeyfrn30gsh ... 1.pdf?dl=0
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RMartins
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Re: The Startek DT-90 Project.

Post by RMartins »

Muttley Black wrote: Tue May 12, 2020 9:19 pm Hello RMartins.

First i have to say that i am not well experience making pcb's. I do every project first for my own pleasure and practise.
That's not a problem, since they are easy to do at home (photo-hatching process), for a single sided, board.
However, for a 2 sided board, you need to be a lot more careful and be 100% sure you have aligned the 2 masks correctly.

I suggest, you drill 2holes in specific opposite places, before applying the masking, since these will help you to align them properly.
WARN: Make sure to drill the holes perpendicularly to the board surface.
Muttley Black wrote: Tue May 12, 2020 9:19 pm The part list yes, It is available (look at the end of this post). About the square footprint that have to be at the pin 1 and only, i mess it around accidentally. It is an easy fix don't worry about that. I try the mimicking by hand method cause i wont the final result to be almost as the original. Trying that by create the schematic first on kicad and then rooting the pcb is hard for me.

Here is the magazine on pdf.

https://www.dropbox.com/s/m1yeyfrn30gsh ... 1.pdf?dl=0
Well, it shouldn't be hard, and there are several tutorials around for it.
But you can use your own method, if you feel more confortable with it.

But I can assure you that it is harder doing it by hand on some graphics package, than using the CAD software to help you.
The learning curve for doing a PCB is not that hard.

The first of a 7 part tutorial
https://www.youtube.com/watch?v=BVhWh3AsXQs
1 -Introduction
2 -Schematic Symbol Creation
3 -Making the Schematic
4 -Associating Symbol and Footprint
5 -Creating a Custom Footprint
6 -Finishing the Layout
7 -Output Files for Manufacturing

or a quick one video, to do everything in one go.
(But I recommend you follow the tutorial above)
https://www.youtube.com/watch?v=PlDOnSHkX2c

Regarding the required materials, are you sure you can still get those specific PAL chips or equivalents ?

WARNING: The article, provides the logic expressions, to be able to program the 2 PAL chips, but you still need a device programmer to be able to program them.

Thank you for the PDF Article.
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Muttley Black
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Re: The Startek DT-90 Project.

Post by Muttley Black »

Thank you for your great tutorial’s. I use Kicad. To be honest I start using Kicad in my 4116 tester, I don’t know if you saw it in hardware section.

About Pal’s the code is available too and this ic’s can be found. I don’t have Pal programmer but when this time come and all I need is that, I ask for help for someone that have one.
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Re: The Startek DT-90 Project.

Post by Muttley Black »

I would be very happy if somehow find a clear photo from both pcb sides, even with the components. That old and not so well pcb prints from the magazine makes my project a bit tricky. What i mean by that? If you look at the pcb mask, the one that have the components layout, LED4 (green/red) with the 3 legs sawing the negative leg soldered in the ground (top side), but in bottom side of the board soldered again in a ground track ( bottom side) but that time through R1 resistor (91ohm) for current limitation. How that led have current limitation in neg leg if already its soldered in clear ground on top side? Or the pcb prints have errors, or i didn't understand that part well.

Image


This problems is the cost if you want to make the pcb same with the original.

From my research, the only person i know who has one Startek DT-90, is one guy from the USA who repairs arcade machines. Is the same guy if i am not mistaken who buy's the last stock from the Startek company. Before some years sold the last one but kept one from himself.

I have send him the emails for some photos or info's but never get an answer. Some people don't wont to help...
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Muttley Black
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Re: The Startek DT-90 Project.

Post by Muttley Black »

Board now finished.

I need to do double checks before the printing process. It is not really matter if this try fail. We always have a second chance.
It was a pleasure for me to recreate that board.

We will see...


Image
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RMartins
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Re: The Startek DT-90 Project.

Post by RMartins »

Muttley Black wrote: Wed May 13, 2020 10:26 pm ... If you look at the pcb mask, the one that have the components layout, LED4 (green/red) with the 3 legs sawing the negative leg soldered in the ground (top side), but in bottom side of the board soldered again in a ground track ( bottom side) but that time through R1 resistor (91ohm) for current limitation. How that led have current limitation in neg leg if already its soldered in clear ground on top side? Or the pcb prints have errors, or i didn't understand that part well.

Image

...
If you look at the schematic in the magazine, page 37, you will see that in fact the double led kathode, is connected to ground through R1.

Which means, the board is either wrong on the bottom, or that image is a mix of both mask sides or similar.

Always follow the schematic, because that is usually how the circuit was designed.
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RMartins
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Re: The Startek DT-90 Project.

Post by RMartins »

Muttley Black wrote: Thu May 14, 2020 10:33 am ...
Image
Assuming the board does NOT have DIP components mounted on both sides, you still have some DIP square pins on the wrong position, that are not in pin 1 position, since they appear on one side of the chips but in some other locations they appear on the other side of the chips. If components are all on the same side (which is usually the case), the pin 1, must be always on the same side of the chip.

It's easy to get confused, when we switch from bottom to top view and vice-versa.

Assuming this is the TOP view of the board, only the 2 chips on the top center appear to have correctly marked pin 1.

EDIT: looking at the the original image again, the one with everything, some of the chips representations do have a ball inside marking the rectangle that represents the chip layout pin 1. And if that is correct, that view should be the bottom (assuming chips are on top), due to the position of those markings.
However, the two top center chips, have no pin 1 marking, but they do have a slot in them.
I would advise you to first, check every track using the schematic on page 37, to properly locate the pins, since the drawing doesn't look reliable.

EDIT 2: Forget everything I said, the chips are in fact on the bottom, so the pin1, looks upside down, and the top center chips, are not chips, but the ZIF sockets which are on TOP obviously, so everything seems to be correct.
Blue marking are on the bottom, black markings are on top.
Sorry for messing it up.
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Muttley Black
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Re: The Startek DT-90 Project.

Post by Muttley Black »

Good morning.

The purple pic it is the top view and only.

More later cause I am at work and from mobile.
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Re: The Startek DT-90 Project.

Post by Muttley Black »

I always check the schematic but keep in mind that do checks on a copy pcb from the "pcb design program" and the schematic it is a pain. I am about 99% sure that the board i make is a good copy and i order some to check them. When they come i put the pcb and schematic front of me and i check tracks with my multi-meter.

It is a prototype board and i don't care so much if it has some errors when they arrive. I tried for no mistakes but i always can cut tracks or bypass with cables if needed in a real pcb.

So, if i found errors i fix them, i do my tests and if all looking good and finally make this dram tester work, i fix the pcb layout and i do new order. Thats time for a checked 100% working PCB's.

That was my thought from the beginning.

The other way was to create the schematic first and then the pcb. That idea was for sure more secure for mistakes, but to root all that tracks, components and vias at the end, to make the pcb layout looks like the original.... That is madness! :D
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Muttley Black
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Re: The Startek DT-90 Project.

Post by Muttley Black »

Τhe actual photos are found but are from a later version.

Image Image
From my research, the only person i know who has one Startek DT-90, is one guy from the USA who repairs arcade machines. Is the same guy if i am not mistaken who buy's the last stock from the Startek company. Before some years sold the last one but kept one from himself.

I have send him the emails for some photos or info's but never get an answer. Some people don't wont to help...
Well... i receive an email today. ;)
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Muttley Black
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Re: The Startek DT-90 Project.

Post by Muttley Black »

The first PCB’s just arrived. A long trip just started till the end. Need to check the board compared to schematic and get the components. :)

Anyone have a PAL programmer?

Image
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Re: The Startek DT-90 Project.

Post by 1024MAK »

PAL chips have been out of production for a long, long time. GAL chips replaced them. But the main manufacturer of GAL chips, Lattice, discontinued GAL chips some time ago (2010/2011) :-(

You can get ‘pulls’ from eBay, and most appear to work okay. Some EPROM/EEPROM/flash programmers can programme (or ‘burn’) the Lattice GAL chips. But not all the Microchip/Atmel types (which are still in production) will be successfully programmed with these ‘unofficial’ programmers.

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Re: The Startek DT-90 Project.

Post by Muttley Black »

Here are the two Pal's i need to find or replace with Gal's: AMD 16L8B-2 PAL & AMD 16R4A-4 PAL.

If anyone have them in stock or can help with replacement ones, please post here.

Thank you
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