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   Copy of Rampak 256K
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   Author  Topic: Copy of Rampak 256K  (Read 797 times)
olivierg
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Copy of Rampak 256K
« on: Oct 16th, 2017, 1:28am »
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Hi All,
 
I received the RamPak 256K Saturday.
It's 4 Layer PCB, more time for create schematic but have finish:
http://www.gossuin.be/images/PsionRamPack/RamPak_256K_V1.0.pdf
 
Now i start the PCB design.
 
The estimate price is 25 euro + shipping.
 
Thanks
Olivier
MartinReid
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Re: Copy of Rampak 256K
« Reply #1 on: Oct 16th, 2017, 11:30am »
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Dear Olivier
 
Looks great (but I don't really understand it). Now show me a carpentry drawing and I'm all over it.
 
I'm following you all the way.
 
Sincerely and in good faith
Martin
olivierg
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Re: Copy of Rampak 256K
« Reply #2 on: Oct 17th, 2017, 1:27am »
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I have finish the 4 Layers PCB layout ans send to production.
http://www.gossuin.be/forum/rampak256k.jpg
I have ordered the components.
Now wait 2-3 weeks.
 
Now I thought about how to test the rampak, initialization by the PSION is enough?
 
 
Thanks
Olivier
« Last Edit: Oct 17th, 2017, 1:33am by olivierg »
MartinReid
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Re: Copy of Rampak 256K
« Reply #3 on: Oct 17th, 2017, 3:02pm »
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Olivier
 
That schematic looks highly impressive. Where does the battery sit? Will the battery be soldered on or in a holder?
 
As for testing / initialising - I'm out of my depth with that I'm afraid, perhaps someone more technical / knowledgeable - like Jaap perhaps
 
When complete - will we be contributing our own pack casing?
 
Still watching with interest.
 
Martin
jaap
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Re: Copy of Rampak 256K
« Reply #4 on: Oct 17th, 2017, 4:29pm »
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on Oct 17th, 2017, 1:27am, olivierg wrote:
Now I thought about how to test the rampak, initialization by the PSION is enough?

 
Initialisation is a good start but not quite enough. Unfortunately the INFO (or Utils/Info on the LZ) only gives precentages and not the actual amount of free space. So you cannot know if all 256K is available. For example, if the top address line was broken, the Psion would see it as a valid 128K pack.
 
To be more certain that the whole memory size is available, run the following small program. I assume that the Rampak is in slot B.
 
OPEN "B:MAIN",A,A$
PRINT SPACE
GET

The number it displays is the amount of free space on pack B. It should be about 262120 bytes on an empty 256K pack.
 
I don't know if the Psion's Rampack initialisation actually does a read/write test of all the pack's Ram. An even better test would therefore be to actually fill the whole pack. If you want, I can write a small program to do that, but I don't think that is really necessary.

Jaap Scherphuis
https://www.jaapsch.net/psion/
olivierg
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Re: Copy of Rampak 256K
« Reply #5 on: Oct 17th, 2017, 6:25pm »
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on Oct 17th, 2017, 3:02pm, MartinReid wrote:
Where does the battery sit? Will the battery be soldered on or in a holder?
When complete - will we be contributing our own pack casing?

 
The battery is soldered using wire, not space for holder.
For casing just use old datapak box.
 
Thanks
Olivier
olivierg
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Re: Copy of Rampak 256K
« Reply #6 on: Oct 17th, 2017, 6:29pm »
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on Oct 17th, 2017, 4:29pm, jaap wrote:

I don't know if the Psion's Rampack initialisation actually does a read/write test of all the pack's Ram. An even better test would therefore be to actually fill the whole pack. If you want, I can write a small program to do that, but I don't think that is really necessary.

 
OK, you can create the code for testing (not urgent), it is prudent to do a complete test.
 
Thanks
Olivier
Mikesan
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Re: Copy of Rampak 256K
« Reply #7 on: Oct 17th, 2017, 7:16pm »
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This project seems to be coming along quite nicely - can't wait to get one!
jaap
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Re: Copy of Rampak 256K
« Reply #8 on: Oct 25th, 2017, 5:12am »
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on Oct 17th, 2017, 6:29pm, olivierg wrote:

OK, you can create the code for testing (not urgent), it is prudent to do a complete test.

I wrote a pack testing program. It can be found in a post on the user subforum.

Jaap Scherphuis
https://www.jaapsch.net/psion/
olivierg
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Re: Copy of Rampak 256K
« Reply #9 on: Oct 25th, 2017, 9:08pm »
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Thanks Jaap.
 
Today i have received the PCB:
http://www.gossuin.be/images/psion/RAMPAK_256K_PCB.jpg
 
Now i wait components but, i have launch order from Farnell for assembling 1 rampak for testing.
 
Thanks
Olivier
MartinReid
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Re: Copy of Rampak 256K
« Reply #10 on: Oct 26th, 2017, 8:38am »
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Dear Olivier
 
Looking good.. Do you need some help with finacing these parts or will it keep until I buy one.
 
By the way as an aside ... The CPC warehouse / trade counter - the UK Brand of Premier Farnell is just down the road from here.
 
In anticipation
 
Martin
olivierg
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Re: Copy of Rampak 256K
« Reply #11 on: Oct 26th, 2017, 6:35pm »
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No thanks, I have order 1pcs of components for prototype from Farnell and use my works account (no VAT and no shipping). For the 'mass' production i order in china is 50% lower price.
 
Thanks
Olivier
olivierg
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Re: Copy of Rampak 256K
« Reply #12 on: Oct 31st, 2017, 10:17pm »
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Hi All,
 
The prototype works  . When I turned on the psion I got the message of 'creating ...', the rampak is well recognized in the utils menu, the Jaap software writes 1023 (block) and display 261888 and after some time 'test passed.  
 
http://www.gossuin.be/images/PsionRamPack/RAMPAK-256K-PROTOTYPE.jpg
 
Just small problem with height of batteries, i can not place the cover but fit without in psion. The RAM chip used is little upper of original, but i have ordered other chip, maybe is lower. Is not the ordered batteries, maybe is lower to.
 
On the 'original RAMPAK' batteries is soldered directly on PCB and i not found at lower price (2,5 euro, is many for me), i have ordered BIOS batterie with wire.  
 
Now wait all parts.
 
Thanks
Olivier  
 
thesourcerer
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Re: Copy of Rampak 256K
« Reply #13 on: Nov 1st, 2017, 9:07pm »
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Have you noticed that the cover on Rampacks has cut-outs in order to accommodate the battery? Obviously Psion had a problem fitting the battery in. I’ve noticed that when I replace the battery in a 32k Rampack, it is 50/50 whether the cover fits OK (even with the cut-outs)!
A tight fit!
thesourcerer
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Re: Copy of Rampak 256K
« Reply #14 on: Nov 1st, 2017, 9:15pm »
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Another small point. I always struggled to solder the 2032 batteries, even after filing/scoring/sanding them. Eventually I got fed up.
Now I use epoxy resin mixed with silver powder (a little bit expensive, but a great time and frustration saver, and it works perfectly)! And when you think about the actual quantity of silver involved, it actually costs peanuts.
Surely someone has done this before?
Haven’t they?
starhawk
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Re: Copy of Rampak 256K
« Reply #15 on: Nov 1st, 2017, 10:21pm »
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...from the resident electronics hobbyist's corner...
 
NEVER EVER SOLDER DIRECTLY TO A BATTERY. You will, at best, dramatically shorten its lifetime -- and you are far more likely to have an exploded battery in your circuit than the better of the two outcomes... doubly (if not more) so with anything lithium-based.
 
The proper tool for this is a special device called a "capacitive spot welder". If all you've got is an iron -- especially a cheap 'rug-burner' (fixed temperature cheapo) -- DO NOT GET THAT THING ANYWHERE NEAR A BATTERY.
 
This is major serious safety stuff here.
 
I will note that, when the battery already has solder tabs on it, if you are careful you can probably solder the tabs without ill effects. Don't sink too much heat into the battery! Even these I wouldn't use a cheapo iron on -- you really need an adjustable-temperature soldering station for that. Set it lower than you normally would use... if you absolutely must solder directly to a battery, set the temp real low, so that it's just barely able to melt the solder. The less heat goes in that battery, the better off everyone is.
 
As for why soldering to them is hard, the casing is steel. Solder doesn't 'stick' to steel (or aluminum) the way it does copper... even aluminum-plated copper is better than steel. Use copper tape, it's cheap on eBay, and it's conductive through the sticky onto whatever's underneath -- or, at least, the roll I got there is. If you won't use tape, you might try a conductive pen, although the resistance of the traces it makes will be incredibly high...
thesourcerer
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Re: Copy of Rampak 256K
« Reply #16 on: Nov 1st, 2017, 11:49pm »
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Thank you for the safety information. Having soldered several hundred batteries with a cheapo soldering iron I can confirm that I have never had a problem with explosions. And no, I am not just lucky, I have an appreciation of thermodynamics, material science, metallurgy and a lot of other things.  
I suspect that you are probably 40 years behind me regarding experience, but yes, quite correctly listen to what the safety instructors teach you in high school!!!
I have never slipped on a wet floor, you can feel when you lose traction long before that happens.
starhawk
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Re: Copy of Rampak 256K
« Reply #17 on: Nov 2nd, 2017, 1:48am »
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I'm 31.
Mikesan
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Re: Copy of Rampak 256K
« Reply #18 on: Nov 3rd, 2017, 11:15pm »
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Starhawk makes a good point.
 
The problem is that people who don't know what they are doing will try to solder to lithium coin cells and as Thesourcerer notes, it is impossible to do because this is a type of stainless steel that is incompatible with the soldering process.  Because it 'won't stick', the uninformed will use more heat, for longer and eventually BANG as the pressure builds!
 
That said, a capacitive welder is even more outside the area of expertise for the average Joe and so perhaps the conductive paint and epoxy trick will work for them.
 
However, the level of technical knowledge on this forum is universally high and so the capacitive welding method does make more sense - it's what the manufacturers do.  
 
So, would anyone like to post circuits and instructions for a 'How-To' on this topic?
starhawk
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Re: Copy of Rampak 256K
« Reply #19 on: Nov 5th, 2017, 4:35am »
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All steels are incompatible with standard electrical solder, as are all other non-cupric metals...
 
Brass is a PITA but it can be done.
 
I must confess I've never used a capacitive welder. I can afford neither to buy one nor to build one... you need "coffee mug" size capacitors for that stuff, and that costs real money.
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