Re: Unknown 1541 add-on card

From: Gerrit Heitsch <*gerrit_at_laosinh.s.bawue.de*> Date: Tue, 25 Jun 2013 21:37:54 +0200 Message-ID: <51C9F192.2040907@laosinh.s.bawue.de> · gerrit_at_laosinh.s.bawue.de

On 06/25/2013 09:22 PM, silverdr@wfmh.org.pl wrote:
>
> On 2013-06-22, at 15:44, Gerrit Heitsch wrote:
>
>>>> I have found a 1541 add-on card with 512 KB DRAM on board. The
>>>> problem: I have no idea who is the manufacturer. So I made some
>>>> pictures:
>>>
>>> 512kB for a 1541? o_O
>>
>> 256KB make sense and were sold, this way you could cache a whole disk in RAM and get (back then) extreme speed over a parallel cable. No more waiting for head movements.
>
> I think it was Roßmöller product. It didn't get much momentum though. Mainly due to the price ("lots" of RAM included) and after inserting disk one had always to wait for the disk to be cached. After this process it was very fast but typical Dolphin/Pro/.. DOS was more practical, reliable and much cheaper AFAIR, while not being /that/ much slower. The PCBs were different though. I think the question remains valid: why are we sure it is a 1541 product? Was it found working in a 1541? If it is a 1541 thing, maybe it was some sort of a prototype expandable for more than one disk..

I did take a look at the TTL support logic. It's the same as on 
TurboTrans 3.0, the Rossmoeller Product you mentioned. The only 
difference is that it contains only the RAM, ROM socket and CPU socket, 
not one for the VIA.

I'd be very surprised if it wasn't for a 1541, maybe for the newer PCB 
revision with the single ROM? The one known as the 1541C.

  Gerrit

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