ZX SPECTRUM REFURB

Jaye · November 2014

Hi, I have an old ZX Spectrum here that I want to fix up cosmetically, the machine seems to be fully operational so I wouldn't want to mess around inside, especially as the keyboard membrane will be a little brittle after all these years I imagine.

The faceplate is a little rattly and I could do with cleaning the rubber keyboard itself. Can anyone suggest a way to safely clean these items without damaging them? Also what type of double sided tape would I use to re-apply the metal faceplate? Lastly the ZX SPECTRUM type, the white has some fading on the ZX writing, is there a special paint that can be re-applied?

Many thanks
Jaye

Zorn · November 2014

New keyboard membranes and reproduction metal faceplates are available at http://www.sellmyretro.com and so you might want to consider those options.

If your Spectrum still has its original/old electrolytic capacitors then I recommend you or someone replace them. They will eventually cause the computer to fail and probably sooner rather than later. In 16/48K Spectrums the lower RAM ICs could well be destroyed when this happens. I've made a video presentation about the procedure: http://www.youtube.com/watch?v=TeCVt2T-YSo. I recommend you don't make it your first unaided project if you have no experience of working with electronic circuits.

I've found most types of general purpose double-sided tape work well for re-attaching the metal faceplate. The key is to make sure every trace of the old adhesive is removed from the faceplate and the case; this is often not an easy thing to do. Also, the faceplate needs to have no non-original deformities or it probably won't stick down properly.

I've never found the rubber keyboard mats to be harmed by soapy water, though it is reported that the printing on some of the early types is not as fast.

Some years ago, I spent several days trying different methods of applying white enamel or acrylic paint to the raised text on the case and was not able to find any that was particularly satisfactory. The best result was obtained by painstakingly applying it a tiny drop at a time using a fine wire.

Jaye · November 2014

Many thanks for the advice. I had a quick snoop at dinner, a quick lift of the lid and the membrane does show signs of age, looks brittle and cracked in places, I really didn't want to remove it, it does seem to work without issue. I wanted to keep this unit as is if I can. It's an issue one with the daughter board that contains the extra ram and the general condition is very good, needs a little TLC, the metal plate is in very good shape apart from where the adhesive has perished on the underside, the rubber keys are a bit dirty so I certainly would like to use the soapy water method on that.

Jaye

Zorn · November 2014

You'll want to be extra careful with it if it's an issue one. Plunging the keyboard mat into soapy water might not be the best thing to do if it's the original, though I can't think of much else to try if there is dirt that won't brush off. Perhaps a cotton bud dipped in distilled water would be the thing to use. Hopefully others will be able to advise.

If the faceplate is loose, it probably would be a good idea to replace the keyboard membrane before sticking it back down. It's hardly a major modification and the original type will eventually just fall to bits.

It's more difficult to know whether the electrolytic capacitors should be replaced. I'd say that if you want to use it, they should be. Failure of one could destroy the lower RAM and that would require much more extensive work to repair. Some tests can be done to gauge the health of the existing capacitors, but they aren't foolproof. I'd probably spend a bit more and use high quality modern axial replacement capacitors and so the original look would be retained.

Jaye · November 2014

Zorn wrote: »

You'll want to be extra careful with it if it's an issue one. Plunging the keyboard mat into soapy water might not be the best thing to do if it's the original, though I can't think of much else to try if there is dirt that won't brush off. Perhaps a cotton bud dipped in distilled water would be the thing to use. Hopefully others will be able to advise.

If the faceplate is loose, it probably would be a good idea to replace the keyboard membrane before sticking it back down. It's hardly a major modification and the original type will eventually just fall to bits.

It's more difficult to know whether the electrolytic capacitors should be replaced. I'd say that if you want to use it, they should be. Failure of one could destroy the lower RAM and that would require much more extensive work to repair. Some tests can be done to gauge the health of the existing capacitors, but they aren't foolproof. I'd probably spend a bit more and use high quality modern axial replacement capacitors and so the original look would be retained.

Really appreciate the info, yes, ideally I'd like to keep it as original as possible, I don't think it will get heavy use, so I might not replace any of the innards, I agree about the membrane, whilst the faceplate is lifted may as well replace that part for a brand new one (thanks for the links)

Again many thanks for the info.

Jaye

balford · November 2014

1) Replace the membrane - it will fail sooner rather than later. Use some double sided carpet tape to restick the faceplate in place.
2) Ditto for the electrolytic caps. Failure here could (and does) take out lower RAM, as others have mentioned. The issue 1, unlike later issues, actually uses a fair amount of radial caps so sourcing these shouldn't be an issue.
3) Don't scrub or wash the Issue 1 keyboard mat, wipe it clean instead. Spirantho on here alluded to this being a very bad idea not so long ago :) Later issues seem to be more resilient.
4) Enjoy it, don't just make it an ornament, use the thing :D

B

Jaye · November 2014

After a quick clean up this unit really is in excellent condition, definitely a keeper for my personal collection. Does anyone know whether or not any issue one ZX Spectrum machines where available at retail? Did the 16k Spectrum get released before the 48k version? I was under the understanding that most issue one machines started out as 16k ZX Spectrums. I've never seen an issue one machine in an original box.

J

balford · November 2014

It's my understanding that issue 1 machines were mail order only, as only 16,000 were produced its a fair bet that most if not all were preorders.

I've read through the Sinclair User archives and it seems that even though the Spectrum was announced in April 1982, machines didn't actually ship until July. The earliest issue 2 machines have datecodes from August '82 which leaves a very narrow window for the sale of issue 1's.

Not concrete evidence, I'll admit :)

The 48k was available at launch from what I read also.

B

1024MAK · November 2014

No, sorry, all Sinclair machines were available within 28 days :lol:

Mark

Spirantho · November 2014

First: Yes, DO NOT wash an issue 1 keyboard in water! Be very careful, the legend will fall off very easily - trust me on this, I know! If it's a darker keyboard you should be OK, though; they're much more resilient.

The Issue 1 Spectrums were available for the first few weeks(?) by mail order only - or maybe just preorder, I don't know. However, they were also used later in the run, up to about 70,000 - but these are refurbs by Sinclair, I reckon, and come with Issue 2 keyboard mats, not issue 1 (Sinclair had a LOT of returns at first, I believe - it only makes sense to fix them and send them back out again with a few modifications). I've not seen a 48K one of these. I think this is where the erroneous "60,000 or so Issue 1 machines were made" came from that Wikipedia is/was guilty of (haven't checked lately) - there were actually about 13,000 made I reckon. I've seen this quite often, just as I've seen Issue 2 Spectrums with the 5C102 ULA.

If you look at eBay item 120638136860, you can see what we use here.
If you look at number 191394697372 you can see one of our Spectrums that we sold after using these pens. You can zoom in on the picture from the front to see it quite clearly.

Changing the caps is a good idea if you want to use it, as is heatsinking the ULA. Luckily the early Issue 1 motherboards have a soldered-down ULA anyway so you just need to fix the heatsink, no soldering required. If you want to keep it original without heatsink, though, I wouldn't recommend using it for long. Issue 1s do not make good workhorses!

Oh, if you do repaint the logo - practice on a cheap Spectrum first! It's not easy to get off if you make a mistake!

ZX SPECTRUM REFURB

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