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[slayer]

Ok, I poached this from another A3000T thread going on at Amibay, this looks like the default jumpers but I can't guarantee the source -:



The jumpers back to factory for the CPU, for the onboard 030:

J100 1-2
J102 2-3
J103 3-4
J104 1-2

J105 ALL OPEN
J106 ALL OPEN
J107 ALL OPEN

[nscaleworld]

Originally Posted by slayer

Ok, I poached this from another A3000T thread going on at Amibay, this looks like the default jumpers but I can't guarantee the source -:



The jumpers back to factory for the CPU, for the onboard 030:

J100 1-2
J102 2-3
J103 3-4
J104 1-2

J105 ALL OPEN
J106 ALL OPEN
J107 ALL OPEN

Thank you so much, I will try these.

I am wondering if it would be wise to install a PPC board in my Amiga 3000T? I have a GVP video card.

[AmiDude]

Originally Posted by nscaleworld

I tried 3 different SCSI ribbon cables, does not fix problem with hard drive not showing up in Workbench 3.1. The ribbon cables are about 6 FEET long. I wonder if they are too long.

6 feet long?! That's way too long. That causes errors, and data loss may occur.
Try shorter cables of 10" - 15" inch max.

[don27dog]

Originally Posted by nscaleworld

So, again, here are the problems:

Amiga 3000T will not boot an 880k disk unless I first disable cpu cach.

Amiga 3000T will not recognize a hard drive after reboot.

Do any of you know what the default jumper settings are for an Amiga 3000T with onboard 68030, I need the default for all of the jumpers on the motherboard.

Thank you.

Oh, and as far as the battery is concerned, I know that Amiga computers work just fine without a battery, but, I do plan on installing a CR2032 battery holder and diode, because I plan to install Workbench 3.9 and I want the correct date and time displayed. Do any of you know what diode I should use? Will a 1N4001 diode work?

Here are the 3000T jumper settings

060
100 3-4
102 1-2
104 1-2
103 2-3

040
100 3-4
102 2-3
104 2-3
103 1-2

030
100 1-2
102 2-3
104 1-2
103 2-3

[shaf]

The Diode for the CR2032 Battery is preferred as a 1N914 although the 1N4001 should work the both have the same VF Characteristics, although the IN914 is the recommended item according to some of the Amiga battery hack files.

[Damion]

Check the chips inside your Amiga 3000 computer. Most of them did NOT have the military-rated versions as supplied by Commodore only to the government. If this is the case, you are wasting your time. Throw that POS in the dumpster where it belongs, and get yourself an Amiga 2000 computer. Connect it to your stereo, load up a sh!tty Amiga game of your choice, and enjoy. Just don't forget to TURN UP THE VOLUME!

[Zac67]

To get something a little more constructive in this thread:

The 'does not boot unless cache turned off' problem may be due to mismatched ZIP RAMs. When the first bank consists entirely of static column (SC) chips Ramsey's burst mode is turned on - but it will only be used for filling the cache.

A problem arises when the rest of the RAMs are not 100% SC (xx4402) but fast page (FP xx4400) - the burst will not work and the machine will crash.

Check if ALL chips are SC and if they're mixed move one of the FP chips to the left frontmost socket.


As to SCSI cable length: we're talking SCSI-1 here, so the cable may be up to 6m (nearly 20'). I'd stay below 3m (for Fast SCSI) to make sure.

Double and triple check termination, some A3ks have misprinted socket labels, so terminator (resistor) packs installed 'correctly' may not work. The 220 Ohm side must go to termpower (5V), the 330 Ohm side to GND. Check whether termpower reads 5V (or close to), the fuse may be blown. If you have the chance try cable terminators, preferably active ones. Most have a LED to show whether termpower is on.

[nscaleworld]

Originally Posted by Damion

Check the chips inside your Amiga 3000 computer. Most of them did NOT have the military-rated versions as supplied by Commodore only to the government. If this is the case, you are wasting your time. Throw that POS in the dumpster where it belongs, and get yourself an Amiga 2000 computer. Connect it to your stereo, load up a sh!tty Amiga game of your choice, and enjoy. Just don't forget to TURN UP THE VOLUME!

What the heck are you talking about dude?

[nscaleworld]

Originally Posted by Zac67

To get something a little more constructive in this thread:

The 'does not boot unless cache turned off' problem may be due to mismatched ZIP RAMs. When the first bank consists entirely of static column (SC) chips Ramsey's burst mode is turned on - but it will only be used for filling the cache.

A problem arises when the rest of the RAMs are not 100% SC (xx4402) but fast page (FP xx4400) - the burst will not work and the machine will crash.

Check if ALL chips are SC and if they're mixed move one of the FP chips to the left frontmost socket.


As to SCSI cable length: we're talking SCSI-1 here, so the cable may be up to 6m (nearly 20'). I'd stay below 3m (for Fast SCSI) to make sure.

Double and triple check termination, some A3ks have misprinted socket labels, so terminator (resistor) packs installed 'correctly' may not work. The 220 Ohm side must go to termpower (5V), the 330 Ohm side to GND. Check whether termpower reads 5V (or close to), the fuse may be blown. If you have the chance try cable terminators, preferably active ones. Most have a LED to show whether termpower is on.

Will the zips actually have SC or FP printed on the chips? What kind of zip memory should I have installed, SC or FP? Where do I check for the 5v termpower? The termination resistor packs on the motherboard were removed so that I have the option of using the 25-pin SCSI port. Right now there is a Commodore terminator plugged in.

[Castellen]

Some good suggestions from Zac67 regarding the memory, certainly worth checking all of the ZIPs are the same. More information here.

Originally Posted by shaf

The Diode for the CR2032 Battery is preferred as a 1N914 although the 1N4001 should work the both have the same VF Characteristics, although the IN914 is the recommended item according to some of the Amiga battery hack files.

As for the RTC backup power supply; you're far better off using a small signal Schottky diode as opposed to a standard silicon diode (e.g. 1N914, 1N4148, 1N400x, etc).

To look at the maths behind it...
From the RP5C01 datasheet we can see the minimum input voltage is 2.2V at a current of 15µA. The RTC has a 1.2k Ohm resistor in series with the battery (see schematic). So it'll develop (1.2k x 15µA) = 18mV, or round to 20mV across it. So the actual minimum voltage at the RTC becomes (2.2V + 20mV) = 2.22V

If a 1N914 diode was used, we can see it has a forward voltage drop of around 0.55V at 15µA. So it'll only provide a clock backup until the cell reaches a voltage of (2.22V + 0.55) = 2.77V. The CR2032 cell is 3V nominal, meaning it only has to discharge by 0.23V to a terminal voltage of 2.77V before it'll need to be replaced, so that's using well under half of the cell's capacity.

If a Schottky diode was used instead, say a common BAT85 for example, we can see the forward voltage drop will be less than 0.24V at 15µA. So the cell can discharge further to (2.22V + 0.24) = 2.46V before it needs to be replaced. You still won't get to use the full rated capacity of the cell (230mAHr), but at a guess you'd still get about 60% of that (140mAHr). At a current draw of 15µA, I'd expect a clock backup time of 389 days or 13 months. Of course that depends on the exact cell being used, age/condition of the cell, exact current draw of the RTC on standby and the temperature.

So in summary, while the silicon diode will work, you'll get far longer out of the coin cell if you use a small signal Schottky diode.

[Matt_H]

Originally Posted by nscaleworld

What the heck are you talking about dude?

It's a joke/reference to a rather insane person we had here (under numerous user IDs) several years back. He had an irrational obsession with A2000s, ceramic-housed ("mil-spec") chips, and throwing away perfectly good hardware that was suffering from minor configuration problems. Core lesson: never, ever, ever enter into any sales or repair agreements with anyone from Beaverton, Oregon.

Back on subject, I think Zac67 and Castellen are putting you on the right track, but I thought of one more thing you might try. Even though the battery has been removed, the SCSI settings can sometimes get garbled - I had a desktop 3000 suffering from this some time ago. If you can get the machine booted, get SetBatt on there and run it with the amnesia flag (SetBatt -a, if I recall) which should clear things up.

I think you should hold off on the PPC until you can get the stock configuration working

[mdivancic]

Originally Posted by nscaleworld

This information, as far as the jumpers, is basicly useless, because it does not tell you what the working default set by Commodore is. What I really need is for someone that has an Amiga 3000T, that they have never messed with the jumpers, to pull the cover off and write down what the jumper settings are for all of the jumpers. Or take a few pictures of the jumpers, showing how they were setup by Commodore. This would help a lot.

Also, why would 880k disks refuse to boot unless you first hold down both mouse buttons and turn off cpu cashe? I have never seen this problem on any Amiga computer. It's got me scratching my head trying to figure it out.

I'm fairly sure the chart tells you, by revision what the jumper settings should be, but hey why bother helping?

[nscaleworld]

Originally Posted by mdivancic

I'm fairly sure the chart tells you, by revision what the jumper settings should be, but hey why bother helping?

So, which set of jumpers do I use, the ones under 313181 -01,-03,-05 or the ones under 313181 -02,-04,-06 ? What the heck does that even mean?

[Zac67]

Will the zips actually have SC or FP printed on the chips?

No, the SCs end in 4402, the FPs in 4400.

What kind of zip memory should I have installed, SC or FP?

SC is slightly faster with an '030 but is harder to get.

Where do I check for the 5v termpower?

One of of end pins of the resistor pack sockets carries termpower (the other's GND). Also in the internal SCSI pin 26 or external pin 25.

The termination resistor packs on the motherboard were removed so that I have the option of using the 25-pin SCSI port. Right now there is a Commodore terminator plugged in.

That's a good config if termpower's working.

[Damion]

Hi Anthony,

To look at the maths behind it...
From the RP5C01 datasheet we can see the minimum input voltage is 2.2V at a current of 15µA. The RTC has a 1.2k Ohm resistor in series with the battery (see schematic). So it'll develop (1.2k x 15µA) = 18mV, or round to 20mV across it. So the actual minimum voltage at the RTC becomes (2.2V + 20mV) = 2.22V

Question - is there any harm in removing and bridging that resistor (R179), when replacing the original battery with a diode and 2032 coin? I've done this on my 2000's, by simply installing the diode (1N60 in my case) in place of the resistor (R803). Based on what you've written, it would seem the RTC battery should last quite a bit longer. Any potential issues with this?

Edit: Just pulled my 2000 from the closet, it's been sitting off for well over a year, and the battery is nearing 3 years old. I was surprised to find that it had only lost 20 minutes. Looks like the RTC on the A2000 is good all the way down to 2.0V, which helps.