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The Memotech MTX Series

     Memotech Hardware Survey Results       

New - see where some MTX computers are hiding in the UK!

This page will be used to record the responses to my Memotech hardware survey - thanks for taking part. If you have not completed the survey - I'd really appreciate it if you could visit it and enter the details of your Memotech equipment, I'm sure we'd all be interested in seeing what is still out there.

If you wish, you can sort the tables by clicking on the column headings

Any unique features of the item will be displayed if you "Mouse Over" the Model Type cell. (This feature will not work if you are using a Smartphone (e.g., an iPhone) or tablet (e.g., an iPad) as they can't support "Mouse Over".) You can see any specific machine details by clicking the Serial Number hyperlink, this will open another page which contains all of the data found so far, including items found elsewhere on the internet.

To see some spurious statistics that we can generate using this data - see the results at the bottom of the page

Memotech Computers

 

Model Type

RAM

kB

Board

Revision

Model

ID

Serial

Number

Location

Origin Owner

Date

MTX512 64 4000-04 512/ 20071 Aberdeen, UK Bought new Dave 20/12/12
MTX512 32 4000-04 512/ 18997 Aberdeen, UK Auction Dave 20/12/12
MTX512 64 4000-05 512/ 15189 Aberdeen, UK Auction Dave 20/12/12
MTX512 512 unknown 512/ 27082 Germany Auction Peter 20/12/12
MTX512S2 256 4000-04 512/ 29073 Germany Auction Peter 20/12/12
Special 32 4000-04 None None (ak1) Southampton, UK Memotech Andy 21/12/12
MTX512 32 4000-04 None None (ak2) Southampton, UK Auction Andy 21/12/12
Videowall 256 4000-04 512/ 33325 Southampton, UK Auction Andy 21/12/12
MTX512 64 4000-06 512/ 26593 Germany Auction Peter 21/12/12
MTX500 32 4000-05 500/ 19759 Germany Auction Peter 21/12/12
MTX512 64 4000-04 512/ 27567 Not disclosed Bought new anon 23/12/12
MTX512 32 4000-04 500/ None (anon1) Not disclosed Other anon 23/12/12
MTX512 64 4000-05 unknown 16193 Not disclosed Other Damien 02/01/13
MTX512 64 4000-05 512/ 16777 Sweden Gift Claus 02/01/13
MTX512 64 4000-05 512/ None (cb1) Sweden Gift Claus 02/01/13
MTX512 64 4000-05 512/ None (cb2) Sweden Gift Claus 02/01/13
MTX512 64 4000-04 512/ 35560 Sweden Gift Claus 02/01/13
MTX500 32 4000-04 500/ None (anon2) Spain Other anon 02/01/13
MTX512 64 4000-05 512/ 17926 Cheshire, UK Bought new Paul 08/01/13
MTX512 512 4000-04 512/ 26091 (anon3) Sussex, UK Auction anon 09/01/13
RS128 128 unknown RS/ 15003 Lancashire, UK Other John 15/01/13
MTX512 32 unknown None None (j1) Lancashire, UK Other John 15/01/13
MTX512 64 4000-05 512/ 18088 UK Bought new Bill 10/02/13
RS128 128 4000-04 RS/ 15118 Finland Other Jani 16/02/13
MTX512 64 unknown None None (mk1) Weston-super-Mare, UK Auction Mark 21/02/13
MTX500 32 4000-05 500/ 15707 Weston-super-Mare, UK Auction Mark 21/02/13
MTX512 64 4000-05 512/ 18109 Weston-super-Mare, UK Auction Mark 21/02/13
MTX500 32 4000-04 500/ 17802 Weston-super-Mare, UK Auction Mark 21/02/13
MTX512S2 256 4000-04 512/ 33096 Weston-super-Mare, UK Auction Mark 21/02/13
MTX512 64 unknown 512/ 22201 Weston-super-Mare, UK Auction Mark 21/02/13
MTX512 64 4000-04 512/ 18976 Sweden Bought new Per 09/03/13
MTX512 64 unknown 512/ 20194 Oxfordshire, UK Other Jim 23/04/13
MTX512 64 unknown 512/ 15166 Oxfordshire, UK Other Jim 23/04/13
MTX512 64 unknown 512/ 32023 UK Other Tony 22/05/13
MTX512S2 256 4000-04 512/ 33261 Aberdeen, UK Auction Dave 09/06/13
MTX512S2 256 4000-04 512/ 33003 Aberdeen, UK Other Dave 31/06/13
MTX512   64 4000-05 512/ 20290 Aberdeen, UK Other Dave 06/08/13
MTX500 64 4000-04 500/ 18233 Not disclosed Bought new anon 04/10/13
MTX500 (ext) 4000-05 500/ 15441 Not disclosed Gift anon 04/10/13
MTX512 64 4000-05 512/ 16849 Germany Auction Stefan 10/01/14
MTX512 64 4000-06 512/ 26722 UK Auction Trevor 15/07/14
MTX512 64 unknown 512/ 15489 Isle of White, UK Bought new Keith 26/07/14
MTX512 64 4000-05 512/ 16471 Aberdeen, UK Other Dave 11/09/14
MTX512 64 4000-06 512/ 35336 Sweden Other Claus 05/11/14
MTX500 ?? 4000-?? 500/ 19210 Germany Bought new Falko 05/01/15
MTX500 ?? 4000-05 500/ 16161 County Down, UK Bought new Steve 08/01/15
MTX512 64 4000-05 512/ 15124 Aberdeen, UK Auction Dave 16/11/15

 

Memotech Add-ons - Memory, Disk Systems, etc.

Model Type

RAM

kB

Board

Revision

Model

ID

Serial

Number

Location

Origin Owner

Date

RS232 board n/a n/a 232/ 15282 Aberdeen, UK Bought new Dave 21/12/12
RS232 board n/a n/a 232/ 15131 Aberdeen, UK Auction Dave 21/12/12
SDX n/a n/a SDX/ 13162 Germany Auction Peter 21/12/12
FDX n/a n/a FDX/ 17155 Germany Auction Peter 28/12/12
RS232 board n/a n/a 232/ 15439 Germany Auction Peter 28/12/12
FDX n/a n/a FDX/ 15545 Sweden Gift Claus 02/01/13
RS232 board n/a n/a 232/ 18296 Sweden Gift Claus 02/01/13
FDX n/a n/a FDX/ 16352 Germany Not known Jan 20/01/13
FDX n/a n/a FDX/ 17061 Germany Not known Jan 20/01/13
FDX n/a n/a FDX/ 16816 Germany Not known Jan 21/01/13
FDX n/a n/a FDX/ 15144 Aberdeen, UK Bought new Dave 22/01/13
FDX n/a n/a FDX/   Aberdeen, UK Auction Dave 22/01/13
SDX 512 n/a SDX/ 32042 UK Bought new Bill 10/02/13
SDX n/a n/a SDX/ 24985 Aberdeen, UK Private sale Dave 05/04/13
RS232 n/a n/a 232/ 17825 Oxfordshire, UK Other Jim 23/04/13
FDX n/a n/a FDX/ 16143 Oxfordshire, UK Other Jim 23/04/13
SDX 512 n/a SDX/ 32074 Aberdeen, UK Other Dave 31/06/13
RS232 n/a n/a 232/ 15716 Aberdeen, UK Other Dave 12/08/14
FDX n/a n/a FDX/ 16855 Aberdeen, UK Other Dave 11/09/14
RS232 n/a n/a 232/ 17011 Sweden Other Claus 05/11/14

 

Memotech Peripherals

Model Type

RAM

kB

Board

Revision

Model

ID

Serial

Number

Location

Origin Owner

Date

DMX80 n/a n/a DMX80 11080 Germany Auction Peter 20/12/12
DMX80 n/a n/a DMX80 11887 UK Other Tony 22/05/13
DMX80 n/a n/a DMX80 None (b1) UK Bought new Bill 10/02/13

 

Conclusions:

Prepare for some spurious statistics! - based on the German Tank Problem

N = total number in the series

k = number of samples obtained

m = highest serial number from the samples obtained

This statistical technique can be used to estimate the maximum of a discrete uniform distribution based on a number of samples and gets its name from its use in estimating the number of German tanks produced in WWII, where it proved to be remarkably accurate.

Using this technique, and the number of MTX devices recorded above :-

As of 21/12/12, k = 10, m = 33325, therefore, the total number of MTX devices produced 36656

As of 02/01/13, using all data obtained to date, k = 39, m = 35560, gives a total   36471

As of 12/02/13, using all data obtained to date, k = 66, m = 35560, gives a total   36097   

As of 10/03/13, using all data obtained to date, k = 74, m = 35560, gives a total ≈ 36039

            [ignoring responses with missing serials, k = 61, m = 35560, gives a total ≈ 36141]

 

As of 16/11/13, using all data obtained to date, k = 82, m = 35560, gives a total ≈ 35992

            [ignoring responses with missing serials, k = 69, m = 35560, gives a total ≈ 36074]

 

As of 26/05/14, using all data obtained to date, k = 97, m = 35560, gives a total ≈ 35925

            [ignoring responses with missing serials, k = 84, m = 35560, gives a total ≈ 35982]

 

As of 05/01/15, using all data obtained to date, k = 102, m = 35560, gives a total ≈ 35907

            [ignoring responses with missing serials, k = 89, m = 35560, gives a total ≈ 35958]

 

 

 - Yes, I know the sample size is small - but I did say the statistics here were spurious!

It is interesting to note that beyond about 20 samples, with no additional high serial numbers, the highest predicted serial number is pretty constant, at around 36,000. In fact, even after only 10 samples, the number is not significantly different at 36636.

If you were to increase the number of samples without changing the maximum serial number observed, the projected total would get smaller and confidence in the resultant number would be higher, but would still be a measure of the number of Memotech devices, rather than just MTX computers. It would seem reasonable to further estimate that the proportion of computers was, say, 90-95% of the calculated total, as individual items such as the RS232 interface, disk controller and 80 column boards used in the FDX were given unique serial numbers too.

You can see the effect of changing the values of k and m using the calculator.

Somewhat more spuriously, you can also enter an estimate for the percentage of units that are assumed to be computers.

User Defined Calculation

Number of Samples, k Highest Serial Number, m

Computer %

 Total Series, N

Assumptions

Assumption Confidence / Justification
  • Serial Numbers began at 00001
I think that this is unlikely, after all, how much confidence would you have had in a computer with a serial number of 1? I think it more likely that Memotech would have come up with an arbitrary starting value of say, 10000. This seems to be borne out by the fact that we have not seen any low serial numbers below 10000. Therefore, the number of computers manufactured is probably significantly less than that predicted from the serial numbers alone.
  • Serial numbers are contiguous
I think that this is fairly likely. As the serial numbers were on printed labels, Memotech were unlikely to miss out any blocks of numbers unless they deliberately wanted to confuse.
  • Serial numbers are unique across the range of Memotech devices
Based on the data retrieved to date, I think that it is safe to say that the numeric part of the serial number used by Memotech was unique, i.e., the number series applied to all Memotech products such that there were not two devices with the same number, so you would not get, say a 512/12345 and a 232/12345. This would mean that the actual number of Memotech computers would be significantly less that the total calculated by entering the serial numbers into the formula above, and we should apply an estimate of the proportion of devices that were actually MTX computers.

Observations

  • The serial number does not give a true indication of the manufacturing sequence of the finished computer. For example, my original "MTX512" has a relatively mature serial number (20071) but is on an early board revision (4000-04). Given that it has had an expansion memory board soldered to the internal edge connector, my theory is that it was an "old" MTX500 motherboard remanufactured as an MTX512.

  • Two of the highest serial numbers (currently 29073 and 33325) were both supplied as part of Video Wall systems, this is consistent with them being produced after Memotech Computers had folded and Memotech Computers Limited had started to concentrate on the Video Wall market.

  • An MTX was sold on eBay.de in December 2016 which had a very unusual Serial Number, it was labeled as "SN 0009". This is the only serial number of this type that I have ever seen, so it is assumed to be a very early example - maybe even a pre-production unit - of the MTX. The calculations and assumptions on this page take no account of, what was probably a very small number, of such cases.

  • I now think that the 10,000 starting number postulated above is almost certainly too low, we have not seen a printed serial number in the 10-11,000 range, although we have seen a number of retrofit serial numbers in this range - all with red, hand written, labels. I think that Memotech renumbered repaired/remarketed machines with "spare" serial numbers below the original assigned range.

  • Serial numbers in the range 11,000 to 14,999 range are all assigned to peripherals, either SDX or DMX80 printers.

  • All MTX computer original serial numbers begin above 15,000

Conclusions

Using the statistical calculation method described and the stated assumptions, I think that it is a reasonable conclusion that there were only around 26,000 Memotech serial numbers issued, which includes all models of MTX computer as well as peripherals and option boards. If we assume that around 5% of that number were options or peripherals, then the total number of Memotech computers sold was probably around 25,000.

This is consistent with, albeit at the lower end of, Geoff Boyd's very wide estimate (see my About page) of 25,000 to 62,500 MTX500/512 computers being produced.