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k2x4b524[
July 18th, 2010, 08:33 PM
I was reading some stuff on Tandy's, non related to this post, but i got thinking... Is it possible to give a 1000-RLX more than 1mb ram? I'm talkin extended memory, since it's a 286 internal but 8-bit to the slot, this should be possible? Or am i just a dog barkin up a metal traffic light pole greased with a really fine coating of SAE-5w10

Chuck(G)
July 18th, 2010, 09:38 PM
How many address lines does the 1000RLX supply on the slot? If it's a standard ISA slot, you have 20 address lines = 1MB available. EMS (or some other bankswitching system) is the only route available through the ISA slot in that case.

leeb
July 18th, 2010, 10:09 PM
...Or am i just a dog barkin up a metal traffic light pole greased with a really fine coating of SAE-5w10

... and I thought I had a challenge with the 2810! :shock:

Cant offer any useful info but will certainly keep watching to hear how things go!
If it works for you I might get one myself... as I like the look of the RLX...
-- it is the 'slim' one, isnt it? :confused:

k2x4b524[
July 19th, 2010, 03:19 PM
The RLX is one of the slim line tandy machines

Chuck, for the 1000rlx, is the ENTIRE system 8-bit except the 16-bit 286? Or just out to the slot, i was thinking piggy-backing the ZIPS might yield some results. if it's 8-bit all the way around, i'm not going to get very far with that

Lord Moz
July 19th, 2010, 03:54 PM
The 1000 RLX is an XT class machine. There is no Gate A20 handler, no cascaded interupt controller, no 16 bit DMA. This is the same situation with the 1000 TL/2. The 1000 RSX (and 2500 series) are full AT class systems.

If you were to attempt you add more than 1MB ram in a PC compatible manner, you would probably have to latch onto the relevant pins at the processor, because I don't think they are routed anywhere on the MB.
You would also have to provide an A20 handler, which is generally provided in AT machines' keyboard BIOS, but I supposed could be patched in latter during the boot process.

This is all my speculation, as I really don't have any circuit level experience at that level.

Anyone else have any other info?
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Trevor

Chuck(G)
July 19th, 2010, 06:33 PM
I found the catalog description of the 1000 RLX here, last page (http://www.thecocolounge.com/files/rscat92.pdf). there's a 512K zip-chip memory expansion kit for it. Looking at the Tandy faxback document (http://support.radioshack.com/support_computer/doc1/1323.htm), the HD came with the 512K expansion installed (Zip chips), the FD has only 512K. Looking at the board layout, it would take a lot of work to do what you want. Stick with EMS if you want more memory on this thing--anything else isn't going to be worth the effort.

k2x4b524[
July 19th, 2010, 07:21 PM
that catalog brings back memories..............
the DMP-240 to me, when i was 10, was the best damned thing that spat out ink
and i didn't know they sold a tandy 5.25 1.2mb external drive for that thing...

Lord Moz
July 19th, 2010, 08:15 PM
I found the catalog description of the 1000 RLX here, last page (http://www.thecocolounge.com/files/rscat92.pdf). there's a 512K zip-chip memory expansion kit for it. Looking at the Tandy faxback document (http://support.radioshack.com/support_computer/doc1/1323.htm), the HD came with the 512K expansion installed (Zip chips), the FD has only 512K. Looking at the board layout, it would take a lot of work to do what you want. Stick with EMS if you want more memory on this thing--anything else isn't going to be worth the effort.

My RLX HD only had the base 512KB, and it took me quite a while to get those zip chips. Either Tandy sold some RLXs with only 512KB, or someone "un-upgraded" mine.
As it happens, the Amiga 3000 uses zip chips in the right format, but it will accept static column or page mode drams, but the RLX wants page mode, if I remember correctly. At any rate, I saw an eBay listing for "Amiga ram chips" and stuffed 'em in the RLX and it happily reported 1MB :)

Later, when I acquired my Amiga 3000, it was fully stocked with its 18MB of ram, but as I had already filled the Tandy, the A3000 didn't need worry :p
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Trevor

Chuck(G)
July 19th, 2010, 08:28 PM
Do you have a part number for those Zip chips? I've got a couple of old laser printer memory expansion cards that are stuffed full of them. Just wondering if they're the same--the printers no longer exist.

k2x4b524[
July 19th, 2010, 08:43 PM
if the part number matches up, i would like one of those printer cards. I have numerous cards that require ZIP chips, aswell as the rlx

Lord Moz
July 19th, 2010, 09:03 PM
I'll open 'er up tomorrow after work and report my findings.

I just bought 2 32MB VME memory boards for the 9U Sun 3/4 VME machines that are LOADED with ZIPs. Crazy. Even better when compared to a 2GB PC2-6400 sodimm :p
The VME boards are for a rebuild project though... no junking them. Trying to recreate my Sun 3/180 I had back in '99-'02 timeframe. Acquiring parts now. Sadly, SMD HDs seem terribly expensive :(
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Trevor

Lord Moz
July 20th, 2010, 05:52 PM
The ZIPs in my 1000 RLX are Toshiba TC514256AZ-80
4x 256Kx4

I hope that helps.
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Trevor

Chuck(G)
July 20th, 2010, 08:37 PM
What I've got are Motorola MCM514256AZ80, so maybe there's a match. Check the datasheets for yourself.