ZX Spectrum 16k Serial Number Discrepancy - Anyone Know Why?

[Stives]

Hi

First time poster here, hoping someone can help unlock a puzzle.

I recently sold, in all good faith, a 16k ZX Spectrum that I have had from new. The serial number on the case is 001-167624, in green lettering. Having received the unit, the buyer contacted me to state that I was trying to “con” them as the serial number on the main board is different, being for a second issue Spectrum, and that I had clearly lied in my listing when stating that I had the item from new. This despite having sent the unit in the original external packaging which clearly showed my name, the name of the Sinclair fulfilment centre and the dates and times of the attempted deliveries by the postal service. Rather than engage in a protracted row , I have simply refunded the money and expect the return of the unit.

My question then is how might this discrepancy have been arrived at? As this was nigh on 40 years ago and family, careers and house moves have intervened my memory is a little hazy but I am certain I had at least one failed unit that I returned to Sinclair. Is it possible they simply swapped out the failed first issue 16k main board leaving a second issue 16k board in a first issue case? By the way, my ex buyer says the Zx Spectrums rarely failed and that had Sinclair swapped the board, they would have put in a 48k board as default, neither of which are my recollections of practice at the time.I have searched this forum, and from at least one of the threads it looks as if that the repair and return practice at the time might make this possible.

Anyhow, I hope someone may be able to help here. It hurts to be called a liar.

[1024MAK]

There is no serial number on the main board / PCB. The PCB does however carry a Issue number. It will also carry one or more numbers/codes related to the PCB production batch. It may also have a date code. Two different issue two boards that I have, have date codes of 8303 and 8310 for example.

There is no known fixed relationship between the serial number on the bottom case and the issue number or date code on the PCB. Or any other numbers or codes on the PCB.

Only a relatively small number of issue one PCB ZX Spectrum computers were made (only about 16,000, that’s why they are desirable by collectors), so it’s unlikely that a ZX Spectrum with a serial number of 001-167624 would have an issue one board. Whereas the issue two boards were manufactured in very large numbers (500,000). Hence these are very common.

Sinclair contracted out the manufacture of the computers it sold. And we think it did the same with the servicing and repairs.

Sometimes when a machine was ‘repaired’, they just put a different working PCB in the same case.

Oh, and for the first year of production, the failure rate of ZX Spectrum computers was terrible. So to say that they rarely failed is absolute rubbish.

Also, the issue one board was limited to only 16k bytes of RAM on board. To get up to 48k, it was fitted with a daughter board. Whereas all later boards (starting with the issue two) had provision for 48k bytes of RAM, although 16k models were still made (the extra RAM not being fitted, instead normally empty IC sockets were fitted).

Did you take a photo of the board, or looking at the rear edge-connector/expansion port? What about of the case bottom?

I suggest you ensure that the buyer sends the computer back to you, as it is possible that they want the computer as well as the refund.

Mark

[Stives]

Thanks for the prompt and informative reply. Case bottom and edge were photographed and used in the sale information.

I have asked for the return of the unit.

Paul

[1024MAK]

See also this site which has more details on the different issue boards and this topic on this forum where a member asks “What makes a Sinclair ZX Spectrum Valuable”.

There is also the ZX Spectrum serial number database here

Mark

[Lardo Boffin]

Hope you get this sorted. Sounds like the buyer is the one doing the conning.

Best make sure all the chips etc. are still present when you get it back.

Bit late to say it but if it was eBay the buyer should have requested a return and then you only refund them when you get the computer back in one piece.