Amiga 500 Rev. 8a.1 mobo. Pro's/Con's?

[brostenen]

So... I recently got hold of an Amiga500, and have used a couple of weeks, just to game on that beauty. Also, I have bought a 512k upgrade from indevidual computers, and everything is fine.

Today I needed to clean the heads with some alcohol, and during the time when it was open, I took off the top shield in order to inspect everything closer. What I found was rather strange, or a surprise, depending how one is looking at it. I found the following....

 - The board are branded a500+.
 - The board revision is "8a.1".
 - It has 512kb Chip-Ram.
 - It has a kick 1.3.
 - It has solderpads for more Ram chips.
 - It has solderpads for battery backed clock.

Now these question lingers in my mind. What are the general perception of this board? What are the upgrade options? What are the pro's and con's regarding this board? (stability and so on). Finally... This is the last non-plus a500 machine released that this board comes from, right?

[Oldsmobile_Mike]

Although officially introduced in 1992, some Amiga 500 Plus units had already been sold (masquerading as Amiga 500 models, and with no prior announcement) during late 1991. It has been speculated that Commodore had already sold out the remaining stocks of Amiga 500s, before the run up to the profitable Christmas sales period. In order to make enough A500s before Christmas, Commodore used stocks of the new 8A revision motherboards destined for the A500+. Many users were unaware that they were purchasing anything other than a standard Amiga 500. Although the Amiga 500+ was an improvement to the Amiga 500, it was minor. It was discontinued and replaced by the Amiga 600 in summer 1992, making it the shortest lived Amiga model.

https://en.wikipedia.org/wiki/Amiga_500_Plus

My opinion:  Good find!  You're lucky it doesn't have a leaky battery.  If it were me, I'd bump it up to 2MB of chip ram, throw in 8MB of fast, a 68010, 3.1, stick some kind of CF or MicroSD card solution on there, maybe an Indivision, and use it as a WHDLoad machine.  Probably the most desirable of all A500-class models since it needs the least amount of work to add things like that 2MB chip ram upgrade.  But that's just my .02 cents, ymmv.

PS - if it's NTSC let me know if you'd like to sell it.  

[scuzzb494]

So... I recently got hold of an Amiga500, and have used a couple of weeks, just to game on that beauty. Also, I have bought a 512k upgrade from indevidual computers, and everything is fine.

Today I needed to clean the heads with some alcohol, and during the time when it was open, I took off the top shield in order to inspect everything closer. What I found was rather strange, or a surprise, depending how one is looking at it. I found the following....

 - The board are branded a500+.
 - The board revision is "8a.1".
 - It has 512kb Chip-Ram.
 - It has a kick 1.3.
 - It has solderpads for more Ram chips.
 - It has solderpads for battery backed clock.

Now these question lingers in my mind. What are the general perception of this board? What are the upgrade options? What are the pro's and con's regarding this board? (stability and so on). Finally... This is the last non-plus a500 machine released that this board comes from, right?

It has 1mb RAM standard. The Plus had the upgrade. Should have the 2.04 ROM for some reason someone has fitted the 1.3. If the battery is still on then remove. If already removed check for damage and possibly do some continuity checks. Also check the underside of the board. Check the pins around the Agnus for corrosion. And just test the machine running.

No great differences in truth as a Plus except the risk of the battery damage. Useful having the RAM but fitting an expansion isn't a problem. ROM could be upgraded.

http://www.scuzzscink.com/amiga/scuzzblog_october17/scuzzblogdoctober17_2303.htm

Probably looks like the above. Hopefully not the below

http://www.scuzzscink.com/amiga/scuzzblog_february18/scuzzblogdfebruary18_2002.htm

[giZmo350]

Hopefully not the below

http://www.scuzzscink.com/amiga/scuzzblog_february18/scuzzblogdfebruary18_2002.htm

That is a thing of beauty! How's does that much dust get inside an A500? It doesn't even have a fan! :eek:

[brostenen]

https://en.wikipedia.org/wiki/Amiga_500_Plus

My opinion:  Good find!  You're lucky it doesn't have a leaky battery.  If it were me, I'd bump it up to 2MB of chip ram, throw in 8MB of fast, a 68010, 3.1, stick some kind of CF or MicroSD card solution on there, maybe an Indivision, and use it as a WHDLoad machine.  Probably the most desirable of all A500-class models since it needs the least amount of work to add things like that 2MB chip ram upgrade.  But that's just my .02 cents, ymmv.

PS - if it's NTSC let me know if you'd like to sell it.  

It is an PAL model. And not for sale.

Thanks. Well... Have considered to upgrade with an 010, yet I want to keep it as stock or near original experience as possible, yet upgrade as much as possible in the long run. In other words, as much as the 010 is cheap in eBay, I really have doubts on if that is the right path to go. (also the reason for me not installing gotek, as I "need" them floppies)

Upgrading Ram! Well... Now we are talking. I have seen a an 8mb that can be mounted between the 68000 and the socket, yet I have no clue on if the top shield can be mounted after that upgrade.

Then comes the kickrom question. I have thought about installing a switcher, as I have an 37.300 floating around. It is the original that was installed in my a600, wich I upgraded to 37.350. Original too, and not going for the 3.x series. Again, to maintain an experience as close to stock experience, from when the machines were originally released.

Regarding storage, then I am thinking about upgrading this 500 to something like a 32mb CF card. For that the 37.300 is perfect in a switcher alongside the 1.3 rom. And that will provide me with a good basic original experience in form of a 500/500+ clone/fusion-kindof machine.

Endivision-ECS's are all out of stock, so I will go the old LCD-flatscreen TV way, as I have access to TV's with Scart input. I live in Denmark, so SCART is kind of the norm here. It is difficult to find HD-Ready flatscreen TV's without SCART here. If anyone ask why not CRT, then the answer is my woman. She instantly get's migrane from tube flickering, so my old 14 inch CRT-TV, is for testing purpouses only.

Anyway...
I guess this machine has some potential's regarding upgrades. Nice.

[brostenen]

It has 1mb RAM standard. The Plus had the upgrade. Should have the 2.04 ROM for some reason someone has fitted the 1.3. If the battery is still on then remove. If already removed check for damage and possibly do some continuity checks. Also check the underside of the board. Check the pins around the Agnus for corrosion. And just test the machine running.

No great differences in truth as a Plus except the risk of the battery damage. Useful having the RAM but fitting an expansion isn't a problem. ROM could be upgraded.

http://www.scuzzscink.com/amiga/scuzzblog_october17/scuzzblogdoctober17_2303.htm

Probably looks like the above. Hopefully not the below

http://www.scuzzscink.com/amiga/scuzzblog_february18/scuzzblogdfebruary18_2002.htm

My machine has 512kb of Chip Ram. And it was never fitted with a battery. So my guess is that it was 500+ boards, refitted to meet the original 500 spec's as close as possible.

[Oldsmobile_Mike]

My machine has 512kb of Chip Ram. And it was never fitted with a battery. So my guess is that it was 500+ boards, refitted to meet the original 500 spec's as close as possible.

Adding something like this should give you 1.5MB of chip:

https://www.ebay.com/itm/Amiga-500-500-512KB-1MB-memory-RAM-expansion-trapdoor-board-like-A501-/252934142608?var=&hash=item3ae40cba90

You may want to verify fully that you have the latest 8375 Agnus (to address 2MB), but considering you have the 8A motherboard you should.  Fill the unoccupied spots on the motherboard to bump yourself up to the full 2MB.

[gertsy]

Adding something like this should give you 1.5MB of chip:

https://www.ebay.com/itm/Amiga-500-500-512KB-1MB-memory-RAM-expansion-trapdoor-board-like-A501-/252934142608?var=&hash=item3ae40cba90

You may want to verify fully that you have the latest 8375 Agnus (to address 2MB), but considering you have the 8A motherboard you should.  Fill the unoccupied spots on the motherboard to bump yourself up to the full 2MB.

Got one of these for my Rev 6. Works well but just using as 512k.

[Methuselas]

It's a terrible board. You'll hate it. You should just send it my way so it can be disposed of properly.

[brostenen]

Adding something like this should give you 1.5MB of chip:

https://www.ebay.com/itm/Amiga-500-500-512KB-1MB-memory-RAM-expansion-trapdoor-board-like-A501-/252934142608?var=&hash=item3ae40cba90

You may want to verify fully that you have the latest 8375 Agnus (to address 2MB), but considering you have the 8A motherboard you should.  Fill the unoccupied spots on the motherboard to bump yourself up to the full 2MB.

I think I have read somewere, that trapdoor ram, used as chipram is not the fastest solution. Will there be differences in speed between upgraded chipram on the board versus chipram in the trapdoor?

[brostenen]

It's a terrible board. You'll hate it. You should just send it my way so it can be disposed of properly.

Joke? (sorry... I am terrible at determin if it's a joke or not) :laughing:

Anyway...
I have had zero software issues with this board, so I will stick with it. As such, it is good enough for me. I am mostly interrested in upgrade options, while retaining the original 500-experience as much as possible.

[Methuselas]

I think I have read somewere, that trapdoor ram, used as chipram is not the fastest solution. Will there be differences in speed between upgraded chipram on the board versus chipram in the trapdoor?

Expansion slot ram will be "slow" fast ram. If you have a 2 mb Agnus, it's better to fill the mobo and leave the expansion alone.

[Methuselas]

Joke? (sorry... I am terrible at determin if it's a joke or not)

Anyway...
I have had zero software issues with this board, so I will stick with it. As such, it is good enough for me. I am mostly interrested in upgrade options, while retaining the original 500-experience as much as possible.

It's a joke. I've had 3 A500s: 1 was a Rev 3, which seemed the most stable and 2 Rev 5, both of which I've had problems with.

[brostenen]

Expansion slot ram will be "slow" fast ram. If  you have a 2 mb Agnus, it's better to fill the mobo and leave the  expansion alone.

Ahh.... Thanks for clearing up. I did "pay attention in class" after all. I remember reading something a bit like that, somewere on the net when searching for Ram upgrades on early Amiga models.

It's a joke. I've had 3 A500s: 1 was a Rev 3, which seemed the most stable and 2 Rev 5, both of which I've had problems with.

No problem... I just had to ask.

[brostenen]

Anyway.... Reading up on revision models late last night. I came to the conclusion, that the regulair a500 with the 8a.1 board, was only produced in a timeframe of less than 6 month's. Probably more like 4 to 5 month's or something. I wonder how many of these were produced all in all, compared to other revisions.