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Author Topic: EPROM/Flash ROM/SRAM expansions (Read 27737 times)

Offline gflorez

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Re: EPROM/Flash ROM/SRAM expansions
« Reply #105 on: 2014.March.03. 10:27:20 »
Observing the problems of Saint or Jitursan with EPROMS, can be those chips too fast for my stock EP?

Online Zozosoft

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Re: EPROM/Flash ROM/SRAM expansions
« Reply #106 on: 2014.March.03. 10:29:47 »
Quote from: gflorez
 I'm thinking seriously to send you it to fix...
Ok, no problem.

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Re: EPROM/Flash ROM/SRAM expansions
« Reply #107 on: 2014.March.03. 10:34:16 »
Quote from: gflorez
Observing the problems of Saint or Jitursan with EPROMS, can be those chips too fast for my stock EP?
No, to fast can not be a problem. And we also use same chips with many Enterprises.

I think some wrong or loose soldering somewhere. Another idea: when you killed the original EPROM probably it is damaged other logic circuits?

Offline gflorez

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Re: EPROM/Flash ROM/SRAM expansions
« Reply #108 on: 2014.March.03. 11:12:49 »
It can be, but is a mystery. If I had killed something the card wouldn't work at all.

Online Zozosoft

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Re: EPROM/Flash ROM/SRAM expansions
« Reply #109 on: 2014.March.20. 22:37:57 »
Now I am testing your card: it absolutely seems to work!
Second strange thing: the "killed" EPROM also works! It contains what I programmed into it in 2009!
« Last Edit: 2014.March.20. 22:55:12 by szipucsu »

Offline gflorez

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Re: EPROM/Flash ROM/SRAM expansions
« Reply #110 on: 2014.March.21. 00:44:41 »
I was expecting that. But, why my EP acts erratically only with it inserted? Can be a broken expansion port?

Yust doing the modifications, was when it begun to fail. I estressed it a lot with hundreds of extractings and insertions.

And the clock, does it react?
« Last Edit: 2014.March.21. 00:51:47 by gflorez »

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Re: EPROM/Flash ROM/SRAM expansions
« Reply #111 on: 2014.March.21. 00:47:45 »
The next step is send you the Ep....

Online Zozosoft

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Re: EPROM/Flash ROM/SRAM expansions
« Reply #112 on: 2014.March.21. 10:50:52 »
Quote from: gflorez
I was expecting that. But, why my EP acts erratically only with it inserted? Can be a broken expansion port?

Yust doing the modifications, was when it begun to fail. I estressed it a lot with hundreds of extractings and insertions.
Do you see any damage on the expansion port?

Anyway offten found contact errors at edge connections (not just Enterprise, also at few years PC's memory or VGA contacts).
The contacts pins looks good, shine, but don't work correctly.
I use Cillit Bang for cleaning contacts. Sprinkle some for soft wipes, thoroughly clean the pins then with dry wipes clean to dry. If the wipes are white originaly you can see how many dirt cleaned!

Offline gflorez

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Re: EPROM/Flash ROM/SRAM expansions
« Reply #113 on: 2014.March.21. 10:59:08 »
No, I don't see damage and the contacts seem clean. I will do a deep cleaning as you suggest...

But..., the weakest part is on the card side, isn't it?  I mean, if something can break, is not it easier that Bakelite connector?

On the other side, I made test with different positions of engagement of the connectors, and sometimes the hangs disappeared and the EP almost worked. But ignore this, I did millions of tests and now I am confused about all the stuff...
« Last Edit: 2014.March.21. 11:17:39 by gflorez »

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Re: EPROM/Flash ROM/SRAM expansions
« Reply #114 on: 2014.March.21. 11:14:25 »
Quote from: gflorez
the contacts seem clean.
As I wrote: "The contacts pins looks good, shine, but don't work correctly."

Quote from: gflorez
The weakest part is on the card side, isn't it?
The experiance: not the card. Especially with the good quality edge connector what your card have (it is have a two connection points for each pins).
I think it because at the card connector always same point contacting, always rubbed. But because the connection have some backlash the connection point on the PCB pin are variable.
And the connector on your card about 5 years old, on the machine about 30 years... more years more dirt :-)

Offline gflorez

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Re: EPROM/Flash ROM/SRAM expansions
« Reply #115 on: 2014.March.21. 11:45:27 »
Sorry I edited my last post.

That's good news if it is just dirt, but rather I prefer to have the card in your competent observation. Use the card as you want. I'm not in a hurry.


Sometimes the card seemed to work, but then I used to play for test that Paszians Rom and it hung or did strange things.

Offline gflorez

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Re: EPROM/Flash ROM/SRAM expansions
« Reply #116 on: 2014.March.21. 11:47:44 »
The error with bad Ram persisted on all my tests.

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Re: EPROM/Flash ROM/SRAM expansions
« Reply #117 on: 2014.March.21. 11:55:49 »
Quote from: gflorez
That's good news if it is just dirt, but rather I prefer to have the card in your competent observation. Use the card as you want. I'm not in a hurry.
I will test it with many different Enterprises. Currently running with Ep128's machine at 7.12Mhz. (I sent photos about this machine to the Internal expansion topic)
Tested the RAM with Normal and Advanced Test modes, and no any problem.
Small demo running for a hours at yesterday.
Will also try the Passians :-)

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Re: EPROM/Flash ROM/SRAM expansions
« Reply #118 on: 2014.June.11. 23:38:32 »
128k Flash ROM socket (for a "dual BIOS" EXOS :-D ) modification on gflorez's spare EP128:
10646-0
10648-1
10650-2
10652-3
10654-4
10656-5
10658-6

Offline gflorez

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Re: EPROM/Flash ROM/SRAM expansions
« Reply #119 on: 2014.June.12. 07:52:19 »
Good move. You have avoided using directly the edge connector pins.