A3010 4 Mbyte RAM upgrade, the Russian way (aka Spider ram)

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Zarchos
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A3010 4 Mbyte RAM upgrade, the Russian way (aka Spider ram)

Post by Zarchos » Sun Jul 03, 2016 6:55 am

OK so I really wanted to try that ...

1st part completed :
Spider RAM.jpg
All pins visually checked to make sure none are 'married' together and all checked for dry joints.


Who will help me, telling me which pin must be soldered to which socket pin on the motherboard ? (I intend to remove the 2 sockets, in fact).
I've started making drawings using a continuity tester and checking each pin of the RAM chips on the IFEL boards (to find the thin long pin each one is connected to) but sthing tells me it's going to be an unreliable solution ... and I'm not the best at reading schematics ... :|

I've got 2 other questions about the IFEL upgrade :
- are the chips disjoined and the fact they are on the same PCB is only for convenience ? (I read that 'yes' but a redundant 'yes' would make me happy)
- are the capacitor (16V, 47 µF, is that right ?) and the 3 CMS resistors (value ? ) that important on the upgrade that I'll have to install them too in my mod ?

munchausen
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Re: A3010 4 Mbyte RAM upgrade, the Russian way (aka Spider ram)

Post by munchausen » Sun Jul 03, 2016 1:29 pm

The two ICs are independent on the IFEL board, it's just easier to lay them out together because it makes the routing easier.

All the extra components on the IFEL board are capacitors (no resistors). They aren't strictly needed but are there for noise filtering. Assuming you get good connections and don't have any shorts, my main concern with your upgrade is noise, so I would strongly advise you to include the caps! But you don't need to use SMD ones.

The RAM pinout is as below (I just did a screenshot from my schematic, the easiest way). I can't remember which end is pin 1 on the A3010 itself.

Sorry I haven't made progress on ordering the boards and parts yet. I'm in the last days of finishing my PhD thesis and spare time is a scarce commodity. However, I'm handing in this week, and then I get some time off (or, time to catch up on my real job) so I should be able to do it soon.
zip ram pinout.png

munchausen
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Re: A3010 4 Mbyte RAM upgrade, the Russian way (aka Spider ram)

Post by munchausen » Sun Jul 03, 2016 1:51 pm

Also I forgot to say: good luck! ;)

Zarchos
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Re: A3010 4 Mbyte RAM upgrade, the Russian way (aka Spider ram)

Post by Zarchos » Sun Jul 03, 2016 3:08 pm

munchausen wrote:Also I forgot to say: good luck! ;)
Hey thanks !
It's great I've got the correspondence table.

All this has got much more chance to fail than work, but at least I'll have tried.
I'm confident, though.

Thanks again !

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1024MAK
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Re: A3010 4 Mbyte RAM upgrade, the Russian way (aka Spider ram)

Post by 1024MAK » Sun Jul 03, 2016 3:14 pm

The capacitors will be there to decouple the power supply lines. One 100nF ceramic capacitor should be connected as close as possible, with the shortest leads possible to the +5V and 0V (GND) connections per chip. That is one capacitor per chip. You may want to use some sleeving to ensure that the leads don't short out to any other connections.

I would not worry about the third capacitor if you are not using a PCB.

Oh, and try to keep all the wires as short as possible.

Mark

Zarchos
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Re: A3010 4 Mbyte RAM upgrade, the Russian way (aka Spider ram)

Post by Zarchos » Sun Jul 03, 2016 4:06 pm

1024MAK wrote:The capacitors will be there to decouple the power supply lines. One 100nF ceramic capacitor should be connected as close as possible, with the shortest leads possible to the +5V and 0V (GND) connections per chip. That is one capacitor per chip. You may want to use some sleeving to ensure that the leads don't short out to any other connections.

I would not worry about the third capacitor if you are not using a PCB.

Oh, and try to keep all the wires as short as possible.

Mark
Thanks.
I've got the sleeving tubes and I'll use them.

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KarateEd
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Re: A3010 4 Mbyte RAM upgrade, the Russian way (aka Spider ram)

Post by KarateEd » Mon Jul 11, 2016 1:20 am

ok, so this post seems only partially complete. I've been wanting to upgrade to 4 M of RAM on my A3010 but no boards around.

Can you tell me what chips you're using and what is 'Spider RAM' or is that name due to the multi-wires?

Do you have a schematic you are following?

Thanks,

Ed......:-)
Ed...... :-)

3 working Beebs, 1 RetroClinic Master, 1 normal Master, 1 A3010, 1 Pi2 RISC OS, 2 broken Beeb Motherboards, 1 Omnibus A7000+ server, 1 A7000+ Desktop, 1 PET, 1 C64, 1 C128, 1 Amiga 500 and 1 Roamer.

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Re: A3010 4 Mbyte RAM upgrade, the Russian way (aka Spider ram)

Post by Zarchos » Mon Jul 11, 2016 6:34 am

KarateEd wrote:ok, so this post seems only partially complete. I've been wanting to upgrade to 4 M of RAM on my A3010 but no boards around.

Can you tell me what chips you're using and what is 'Spider RAM' or is that name due to the multi-wires?

Do you have a schematic you are following?

Thanks,

Ed......:-)
Yes, that's the MT4C1M16C3DJ-5 as described in the thread 'Today I overclocked my A3010' and they are available from AliExpress.
http://fr.aliexpress.com/item/MT4C1M16C ... ba76495316
Yes Spider ram comes from the fair amount of wires ...(blame it on Steve3000 who found this very inventive name ah ah :roll: )
I've got some schematics, yes, provided by Munchausen. (Thanks again !)
I'm not home until tomorrow when I will try to wire all this, to see if it works or smokes ;-)
Give me a few days to report here the results.
The idea is to have a cheap way to upgrade the A3010s, because, as you noted, the memory expansions are unavailable ; but it's also to be able to overclock these machines, with these 50ns DRAMs.

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KarateEd
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Re: A3010 4 Mbyte RAM upgrade, the Russian way (aka Spider ram)

Post by KarateEd » Mon Jul 11, 2016 1:30 pm

Excellent, I very much am looking forward to this project......and your results. I'm hoping no smoke, good speed..... :D

Ed......:-)
Ed...... :-)

3 working Beebs, 1 RetroClinic Master, 1 normal Master, 1 A3010, 1 Pi2 RISC OS, 2 broken Beeb Motherboards, 1 Omnibus A7000+ server, 1 A7000+ Desktop, 1 PET, 1 C64, 1 C128, 1 Amiga 500 and 1 Roamer.

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Re: A3010 4 Mbyte RAM upgrade, the Russian way (aka Spider ram)

Post by vectorlight » Wed Jul 13, 2016 9:56 pm

Zarchos wrote:I'm not home until tomorrow when I will try to wire all this, to see if it works or smokes ;-)
Give me a few days to report here the results.
Did you manage this Zarchos or did it smoke? :twisted:
3D Printing and Acorn A3010 Owner!

Zarchos
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Re: A3010 4 Mbyte RAM upgrade, the Russian way (aka Spider ram)

Post by Zarchos » Thu Jul 14, 2016 6:15 am

vectorlight wrote:
Zarchos wrote:I'm not home until tomorrow when I will try to wire all this, to see if it works or smokes ;-)
Give me a few days to report here the results.
Did you manage this Zarchos or did it smoke? :twisted:
Well I've been busy so not tried yet but it's scheduled for tonight.

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Re: A3010 4 Mbyte RAM upgrade, the Russian way (aka Spider ram)

Post by Zarchos » Fri Jul 22, 2016 8:29 pm

The experiment failed.
Good news now I'm going to focus on the Bad Apple demo :wink:
I'll try again tomorrow to check the wires but honestly once everything is soldered it's just impossible to trace which goes where.

OK so I checked because I was very surprised it didn't work, the soldering is quite good, really.
So the answer : I read the onboard connector pins numbering with pin 1 at the top (North) when in reality it's at the front (South). =D> :mrgreen:

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Re: A3010 4 Mbyte RAM upgrade, the Russian way (aka Spider ram)

Post by munchausen » Sun Jul 24, 2016 2:09 pm

Zarchos wrote:The experiment failed.
Good news now I'm going to focus on the Bad Apple demo :wink:
I'll try again tomorrow to check the wires but honestly once everything is soldered it's just impossible to trace which goes where.

OK so I checked because I was very surprised it didn't work, the soldering is quite good, really.
So the answer : I read the onboard connector pins numbering with pin 1 at the top (North) when in reality it's at the front (South). =D> :mrgreen:
Oh no! Are you going to resolder and try again?

Zarchos
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Re: A3010 4 Mbyte RAM upgrade, the Russian way (aka Spider ram)

Post by Zarchos » Sun Jul 24, 2016 5:39 pm

munchausen wrote:
Zarchos wrote:The experiment failed.
Good news now I'm going to focus on the Bad Apple demo :wink:
I'll try again tomorrow to check the wires but honestly once everything is soldered it's just impossible to trace which goes where.

OK so I checked because I was very surprised it didn't work, the soldering is quite good, really.
So the answer : I read the onboard connector pins numbering with pin 1 at the top (North) when in reality it's at the front (South). =D> :mrgreen:
Oh no! Are you going to resolder and try again?
Yes but not in the near future.
I'm more interested by the SIMM solution, now I bought a lot of 50 ns 4 Mbyte modules at an interesting price (ie cheaper than 2 x 50 ns 2 Mbyte chips).

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