A3000T Rebuild

[Unicorn]

So I have an A3000T that was given to me some years back.

Some users here have convinced me it is worthwhile to get it up and running again.

The machine seems to have the latest buster agnus etc, it seems to have 2MB chip ram and either 2mb or 4mb fast ram.

It has a standard sized PC power supply hiding inside the case of the A3000T power supply. The power connector is not connected to MB also the Battery was removed years ago.

The mains cable runs to the power switch on the front.

Unfortunately the keyboard switch fell apart when touched.

Does anyone know of a replace barrel switch.

Does anyone have a photo of the power connector colours to confirm the voltage is going to the right pins.

Thanks

[mousehouse]

Hi!

Good project to bring an Amiga 3000T back to life, really nice machines IMHO.

Attached a photo of my 3000T where you can see the colours to the MB from the power supply. I also have the service manual somewhere that I could put in the Zone for you if you do not have it.

PSU pins should be : http://www.hardwarebook.info/Amiga_3000T_Power_Supply

As for battery, I soldered two wires to the bottom of the PCB on the battery pins and connected a 3.6V phone battery pack. Works like a charm. I'm sure I have pictures of that as well somewhere...

[Unicorn]

Originally Posted by mousehouse

Hi!

Good project to bring an Amiga 3000T back to life, really nice machines IMHO.

Attached a photo of my 3000T where you can see the colours to the MB from the power supply. I also have the service manual somewhere that I could put in the Zone for you if you do not have it.

PSU pins should be : http://www.hardwarebook.info/Amiga_3000T_Power_Supply

As for battery, I soldered two wires to the bottom of the PCB on the battery pins and connected a 3.6V phone battery pack. Works like a charm. I'm sure I have pictures of that as well somewhere...

Great thanks.

I found a comparison of atx and A3000t pins but I just don't know who has done what to this machine. I don't want to kill the machine first go.

I am not sure what the white fuz is on the board, but I have to remove the board to find the bits of the keyboard lock.

I think I also have a cyberstorm MK I and MKII around somewhere.

[mousehouse]

If you take the system apart anyway, probably a good idea to do the INT2 modification (run a wire on the back side of the motherboard between the CPU slot and another pin on the CIA's I believe). That way SCSI on the accelerators works ;-) Let me know if you need to know which pins, I have photo's from mine.

[DarrenHD]

Originally Posted by Unicorn

Great thanks.

I found a comparison of atx and A3000t pins but I just don't know who has done what to this machine. I don't want to kill the machine first go.

I am not sure what the white fuz is on the board, but I have to remove the board to find the bits of the keyboard lock.

I think I also have a cyberstorm MK I and MKII around somewhere.

I recently got a used A3000 and it also had alot of white fuzz, lots around the CPU fast slot, and in other places. The battery had leaked in this A3000 and it also had green residue in many places. I cleaned as much of it off as I could. The white fuzz came off pretty easy with isopropyl alcohol. For the green stuff I used vinegar, distilled water, and isopropyl alcohol. Most of it came off. It's clear though that it's "old" and you can really see the metal fatigue/age on the chip pins. Luckily most of it still works - I have an issue with Amber(flickerfixer) not displaying some resolutions properly but that is probably easily fixed by replacing a few chips, and of course the clock doesn't hold time, although the system does find the clock (check with SysInfo, it should say "Clock Found!". I'm sending it out to be repaired as I've done as much as I can with it myself.

The MKII should work fine in the A3000(T), check for jumper settings - google it and you will find it.

Bottom line, be very careful and patient working around the board. Due to the age they are pretty fragile and the metal pins on the chips can easily break (I've broken pins off one of the chips myself . Also use the proper tools if you are going to be pulling chips out of sockets...otherwise there is a huge risk you will break a pin.

Darren

[Hedeon]

Originally Posted by mousehouse

If you take the system apart anyway, probably a good idea to do the INT2 modification (run a wire on the back side of the motherboard between the CPU slot and another pin on the CIA's I believe). That way SCSI on the accelerators works ;-) Let me know if you need to know which pins, I have photo's from mine.

I only just now noticed that there is a lot of conflicting info on the presence of the INT2 signal at the A3000T CPU slot.

[Jope]

INT2 was not present in my A3000T at least.

[mousehouse]

Originally Posted by Jope

INT2 was not present in my A3000T at least.

Same here... Did the fix when I got the machine ~8 years ago (?)

[Hedeon]

See for example https://www.bigbookofamigahardware.c...uct.aspx?id=22

Which says:

INT2 Modifications

Certain accelerators, primarily those with onboard SCSI may require the INT2 modification to function fully. The A3000's CPU Fast Slot does not contain the INT2 signal as found on the A3000T, A4000 and A4000T. An INT2 modification guide can be found here.

Well, I guess one has to check.

[Unicorn]

Originally Posted by Hedeon

See for example https://www.bigbookofamigahardware.c...uct.aspx?id=22

Which says:

INT2 Modifications

Certain accelerators, primarily those with onboard SCSI may require the INT2 modification to function fully. The A3000's CPU Fast Slot does not contain the INT2 signal as found on the A3000T, A4000 and A4000T. An INT2 modification guide can be found here.

Well, I guess one has to check.

Now I have to wonder does the 3000T have the INT2 mod. My guess is this machine was well looked after until the power supply failed. So I guess it would have been done if needed.

It has the latest IC's on it. The funny fail seems to be that someone did all of the work to build a new power supply. Looking at the wire colours referenced earlier it looks good. BUT, the power supply does not reach to the connector. I think it was a FML moment that stopped the repair of the machine.

So I can possibly just get an ATX extender to bridge the gap.

[Wrangler]

I've tried using an ATX power supply (with significant amps on the 5v line) with an A3000T via an adaptor I made, but the machine struggled to get enough power even to display the insert floppy screen without video corruption! I have a feeling the power socket on the motherboard had corroded a bit so that is something to watch. Curious whether it's OK or not for you.

[Unicorn]

My A4000 converted to a tower has been running many years trouble free on an ATX power supply well 2 one died and was replaced.

That machine has 16MB ram plus Power PPC +128MB of ram, BVision, AriadneII, Vlab Motion, Tocatta, Emplant and 5 9GB SCSI drives.

I pulled the power supply out of A3000T to see if I can get it to reach the connector. I can also research its model and ratings.

I could hack the hole the standard A3000T power cables come out of to get the length right.

My guess is that this is a an AT power supply with the A3000T 24 pin connector on it.

Pin 1 seems to be wrapped into the cables but not connected, this I assume is the tick.

I wil get the board out and clean it over the weekend.

[AmigaHope]

Treat that machine well. A3000Ts are rare and are probably C='s finest hour in Amiga design.

[Unicorn]

I actually found the A3000T power supply from this machine. The person who owned it had desoldered the A3000T connector from the powersupply.

I noticed it due to commodores orange leads on the molex plugs.

The question then is should I rebuild the original power supply or try and adapt a PC power supply.

I also found 10 Milk crates of big box Amiga Programs. Who says hoarding can't be fun.

[dalek]

I'd recommend Ian's ATX adapter and a new PC ATX PSU transplanting the internals in to your old 3000T PSU housing. I've used Ian's adapters in a few projects now and they are by far an away the best solution.

http://www.ianstedman.co.uk/Amiga/de...x_adaptor.html

[Unicorn]

Originally Posted by dalek

I'd recommend Ian's ATX adapter and a new PC ATX PSU transplanting the internals in to your old 3000T PSU housing. I've used Ian's adapters in a few projects now and they are by far an away the best solution.

http://www.ianstedman.co.uk/Amiga/de...x_adaptor.html

Unfortunately it seems ordering is not available for the moment.

I might be able to use an extender for the moment.

Darren

[Unicorn]

Originally Posted by mousehouse

If you take the system apart anyway, probably a good idea to do the INT2 modification (run a wire on the back side of the motherboard between the CPU slot and another pin on the CIA's I believe). That way SCSI on the accelerators works ;-) Let me know if you need to know which pins, I have photo's from mine.

OK I saw on another thread that the A3000T does not need an Int2 mod.

Can anyone confirm this as I have finally received my lithium batteries for all of my Amiga's.

I am about to start rebuilding these machines.