Suitable for RiscPC, A7000, A7000+


Important Information

We supply a range of new, reconditioned and pre-owned computer hardware suitable for use with computers that run RISC OS. We don't normally supply complete computers only computer components. In order to use these products they will need to be fitted to a computer by someone with suitable expertise. All items are sold mail order, we do not accept callers so it won't be possible for a customer to pick up an order.

Product Information   Grading   Installation   Support   Guarantee   Substitution

128MB SIMM for RiscPC/A7000

A standard 128MB SIMM (Single Inline Memory Module) suitable for RiscPC or A7000/A7000+ computers. When used in the RiscPC it can be fitted on its own to provide 128MB or a pair can be fitted to provide 256MB. if you order two of these SIMMs they will be supplied as a matched pair (same manufacturer/make/model).

Now in stock - £50.00 (Plus P&P)

Out of stock


Detailed information

  • Standard size memory SIMM for use with RiscPC or A7000/A7000+ computers.
  • Soak tested by 3QD Developments Ltd with test date on packaging.

  • Manufacturer : Various
  • Condition : Reconditioned
  • Designed for : RiscPC, A7000, A7000+
  • RISC OS version : n/a.

Product grading

Acorn Computers Ltd closed its doors in 1998 so, as you would expect, the Acorn branded hardware we supply is pre-owned rather than new. Items that are were not made by Acorn Computers Ltd but that are 'Acorn compatible' may be new, pre-owned or reconditioned, the grading will be shown with the key information for the item. The full grading listing for the hardware products we sell is:

  • New - a product that has never been made available for retail sale, is boxed with all packaging and contents.
  • New Old Stock (NOS) - a product previously held by a dealer but not sold to a retail customer. Packaging may have scuffs, contents will be unused.
  • Reconditioned - a pre-owned product that has been cleaned, inspected and tested by APDL. May have signs of light use. Supplied in non-original packaging, may lack instructions.
  • Secondhand - a pre-owned product that has been tested but has clear signs of use. Supplied in non-original packaging, may lack instructions.
  • Spares/Repairs - a product from the above categories that is either incomplete or does not operate correctly. May not have any instructions or original packaging. Sold as seen with no guarantee as to fitness for purpose.

The section New Old Stock (NOS) deserves a little explanation. In many cases components may be, in all normal sense of the word, 'new' but because they have been previously held by a dealer and then sold to another dealer they are classed as 'secondhand' in the EU. For example we have stocks of three button Acorn compatible mice that were manufactured in the 1990's. These were supplied to a dealer but were never sold. The dealer then sold them as 'job lot' to another dealer. This dealer then sold them to APDL and when APDL closed we obtained the stock. These mice have been sold several times over, but the boxes have never been opened and the mice have never been used.


We are a small mail order company and we are not able to offer an installation service for products we sell. It will be the responsibility of the purchaser to install and configure any products purchased from us. If you do not feel confident about performing the installation yourself you can contact one of our registered installers who should be able to assist.

Some hardware devices will require driver or support software. This will be supplied either on RISC OS format floppy discs or via a download link at the time of purchase.

Technical Support

All products (except those marked as spares/repairs) are sold with phone/e-mail support for a minimum of six months from the date of purchase. We will only offer support for products that have been purchased from us (3QD Developments Ltd). This support will only cover the normal use of the items purchased. If you are buying a hardware upgrade it will need to be fitted by someone with the necessary skills. We won't be able to talk you through disassembling a computer to fit an upgrade, but we will assist if you have correctly fitted an upgrade and it's not working.

Support Documents

Important fitting notes

The RiscPC can accept two memory modules, the A7000 can only accept one. The maximum amount of RAM supported per SIMM is 128MB. If you want to fit 2 x 128MB SIMMs to a RiscPC you will need to be running RISC OS 4.39 or later. RISC OS 4.02 and earlier only support a maximum of 128MB (as either 1 x 128MB SIMM or 2 x 64MB). Some early RiscPC motherboards have what's known as 'High Clearance' sockets. See the section under the fitting diagrams below for more details.

You will have to disassemble the case to fit the memory SIMMs. If your RiscPC has expansion podules these will need to be temporarily removed to gain access to the sockets.

One of the more common problems with the design of RiscPC is timing. Some motherboards will happily work with any compatible SIMMs and work with different size SIMMs from different manufacturers. Other apparently identical motherboards will only work with matched pairs (two SIMMs of identical size/make/model). The faster the processor fitted the more likely the problem is. Our advice is to only use matched pairs of SIMMs in computers with a StrongARM processor. If you order a pair of SIMMS of the same capacity we will supply a matched pair


Fitting location RiscPC motherboard

Fitting location A7000/A7000+ motherboard


IMPORTANT - Risc PC 600 High Clearance sockets

The early RiscPC 600 machines were fitted with SIMM sockets which were higher than on more recent machines so many modern double sided SIMMs won't fit. On these machines you need to fit High Clearance (HC) SIMMs. If in doubt check the model number in the centre rear of the motherboard. If this is 0197.000 you need HC, if it's 0197.100, 1208.000 or any other number) you don't. You can't tell from the RiscPC's serial number as so many machines have had replacement motherboards or have had other parts swapped around. The only way you can tell is by looking at the model number printed on the motherboard.

If you do need HC SIMMS for a RiscPC please contact us prior to ordering as stocks are very limited and we normally ship standard height SIMMs.

A7000+ High Clearance sockets

A very small number of early A7000+ computers have a slightly higher socket because the plastic molding is fractionally too tall for standard SIMMs. In this case we recommend carefully trimming with a stanley knife to enable the SIMM to fit.

RiscPC 0197 motherboard modifications for SIMMs over 32MB

All RiscPC 600 motherboards with an 0197 number were fitted with capacitor C32. This was intended to improve stability with large amounts of RAM. However when larger capacity SIMMs appeared (they didn't exist when the RiscPC was designed) it was found to have exactly the opposite effect. If you intend to fit SIMMs larger than 32MB you should remove this capacitor. It's a small surface mount device, and is located as shown below.

It's easily removed using a normal soldering iron but if you have any doubts about your ability to do this then don't touch it. If you mess it up you could damage the motherboard. If you don't have a friend you can trust then most TV repair shops would do it for a few pounds


The Consumer Rights Act 2015 (effective 1st October 2015) states that all products must be as described, fit for purpose and of satisfactory quality. All of our products comply with these regulations. As many of our hardware products will be pre-owned they may not have as long a life span as a brand new device and this will be reflected in the price we charge. We offer a 6 month warranty on hardware. If a product fails after the 6 month period it may still be covered by our warranty if the failure is down to an inherent fault.

If you do need to return a product please contact us first to arrange a returns number. We will test the product once it's been returned to us. If it's faulty and inside the warranty period we will either replace it or offer a refund depending on how long the product has been in your possession. If the product doesn't work because it's been damaged or misused we will not replace it or offer a refund.

For full details on our guarantee and warranty click here to read our full terms of business.


In very rare cases we reserve the right to supply a substitute Reconditioned or Secondhand product rather than the product shown. We will only ship a substitute product if it offers the same (or better) functionality as the item originally ordered. For example: we may send a RiscPC network interface that's made by a different manufacturer. You may request that we don't ship any substitute products by contacting us before placing an order.



© Copyright 3QD Developments - 24/06/2024