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[bash64]

Hello,

Just bought a DKB 2632 and populated it with 112mb ram.
Jumper J3 is for adding a wait state for 100ns ram.
80ns ram is supposed to be used with the board.
However, the manual does not tell you what the default state of the jumper is (on/off) and does not tell you how to jumper for 100ns ram (on/off). Who ever wrote this documentation needs to LEAVE the computer industry for the sake of us all.
:-D

Check out the .pdf docs at amiga hardware database.

So, I need to know how to jumper for 80ns ram (my ram is 60ns).
Anyone?

[Jeff]

I'm pretty sure ON adds a wait state and OFF removes the wait state. Here is an old picture of mine (it has since been updated with 32 meg SIMMs). The SIMMs shown look like 70ns.

DKB 2632

-Jeff

[Tenacious]

Hi Jeff,

I bought a 2632 a few months back as well as a rom upgrade for the 2630. There is a grab bag of 72 pin simms (I must find a way to evaluate or get specs on these) in the basement and I have yet to install it all.

In your pic post, you mentioned information from Dave Haynie for installing a 1K resistor on the motherboard. Could you post or link to Dave's thoughts on the subject?

[Zac67]

Possibly here?

[Tenacious]

Thanks Zac.

I read through all of those texts. They seem to discuss DMA problems with the A2630 (no mention of the 2632) and MBs after rev 6.x with A2091s. I could find no specific mention of a simple 1K resistor alone to fix the problem.

There must be another fix Dave sent out, perhaps mentioning the 2632 also.

[rkauer]

Better way to know the speed of a SIMM is looking the suffix of the RAM chips in it.

80ns are marked -8, 70ns is -7 and so on.

[Jeff]

Here is the information about DMA issues and the A2630/A2000/A2091. I never could get this combination to be reliable until I added the resistor mentioned in the text. It is a 10 minute 25 cent fix that really makes a HUGE difference. This worked on a Rev 6.2 2000 as well.

-Jeff

Subject: Re: A2630 fix question

> I had lots of problems with my 2000/Rev4.3, A2091, A2630Rev9.2
> setup until someone told me, that there were some resistor packages
> soldered in the wrong orientation on the A2630 (RP104-RP107). I
> looked at the board and I saw, that they had their common pin
> on the other side than the drawing on the board (now I know what
> it is good for)

That's odd...

> My question: Was there any good reason for turning the RPs or was it
> just an error that happened during the production of the board?

I suppose it might have been intentional. I didn't do it that way, but
I didn't really touch the A2630 after Rev 6. Pretty much everything
done after that was to FCC certification. It's possible that these
resistors, which I believe I had in there for data bus pullups, were
switched around to act as pulldowns. If you lay out the resistor pack
footprint right, you have +5V at pin 1, Ground on the last pin, and so
you can get "proper" behavior with either orientation. I've been been
a big fan of pulldowns on bipolar logic (typically, bipolar output
stages can drive a great deal of current low, but not so much high),
but they do tend to limit the peak voltage, and occasionally over-peak
spikes, when a signal swings high. This is good for FFC certification,
and not bad for typical system operation in most cases. Apparently you
have found one of the cases in which pulldowns can be a problem.

Or perhaps you're trying a complex fix for a simple problem already
solved in most systems. I don't know what you had failing, but if it's
DMA between the A2091 and A2630, there's a known problem on some A2000
motherboards. Certain vendors versions of the 74ALS245 chip used at
U605 on the A2000 motherboard cause a problem, a potential glitch on
the BAS* (buffered address strobe) line of the Zorro II bus, during
DMA turnaround (when the A2091 drops the bus and the A2000 logic picks
it back up). This glitch is nicely shaped into a pulse by the ALS245's
schmitt input, but that pulse on AS* is ignored on the motherboard,
it's not long enough to usually affect the 7MHz logic on the A2000. It
is long enough to mess with the 25MHz logic on the A2630, however. To
fix this, you add a 1K pullup between pins 11 and 20 on U605 (which
you'll find between the CPU and first Zorro slots).

Maybe changing the A2630 resistor packs to pullups helps, too, I never
really looked at the problem. But this resistor fix makes a very big
difference, you might want do it even if your system is working find
now, just to be safe.

-Dave Haynie

[Tenacious]

You guys have inspired me.

I tested all of the simms in a Quadra 605. They are 1 32Meg, 3 16Megs, 3 8Megs, and 2 4Megs. The 32Meg will go in the Quadra since it has only 1 slot. Two 16 Megs and two 8 Megs will go in the 2632, yeilding 48 Megs. Not bad at all!

They are all 60ns. Thanks rkauer.

When I recieved this machine, I could not update the Kickstart from 1.3, I'm told because of the roms (Rev 4) on the A2630 (Rev 9.1). The Rev 6 roms will be tried after the ram configuration is confirmed. Got the newer roms from someone here.

Motherboard is Rev 6.2, the A2091 has Rev 7.0 roms but no ram installed. Should I have some 16-bit ram on the A2091 to improve performance? It came from Commodore as an A2500 configured without 16-bit ram.

Thanks Jeff for the notes from Dave. I'm going to try it without the resistor first, worked without it before.

Wish me luck.

[Tenacious]

Yeah! It works!

I don't seem to have all the memory recognized yet and there seems to be a discrepency between Workbench total and SysInfo.

I did install Kickstart 2.04 as well and it works with the new roms on the A2630.

This machine needs a bigger harddrive and a CDrom drive now. It still has the original 40 Meg HD.

Maybe tomorrow, I need some sleeeep.

[bash64]

Thanks.
The default appears to be the ON position.
The board would lock up using the 2632 command with it OFF.

I am using 96MB of 60ns ram.

I have a GVP HC+8 scsi card so I don't have the dma issue.
I have the DENEB card and am working on booting off of a thumbdrive anyway.
Almost there......

Did you know that the OS 3.1 disks have a mathematical error that messes the install up if your partition is bigger than 2GB? Even though 4GB drives work fine and can be used to boot? Took me four hours to learn this the hard way.
:-(

Looking to buy a CSA Rocket Launcher

A2630 Rev 9.2
DKB 2632 w/96MB ram.

P.S. I do not have the long power connector on mine. Just a 5 1/4" female molex connector on the dkb 2632.

[TjLaZer]

Originally Posted by Jeff

Here is the information about DMA issues and the A2630/A2000/A2091. I never could get this combination to be reliable until I added the resistor mentioned in the text. It is a 10 minute 25 cent fix that really makes a HUGE difference. This worked on a Rev 6.2 2000 as well.

-Jeff

Jeff, got a pic of the mod? Which way do you install the resistor? I think I need to do this mod on my A2000. I get lockups on my A2630 w/2632 RAM card. I did pinpoint that it does not seem to crash when the RAM is OFF.

[Matt_H]

I have major lockup problems with my 2630/2632 as well. I've got it partially stable with just a single SIMM installed, but I'm interested in seeing details of this mod, too. Would love to get this machine rock solid!

TjLaZer, what revision is your motherboard?