Powering up a Speccy after long-term storage.
Staying at my folks for Christmas. Feels good to be back in God's country again, even if it is -12C outside at the moment. :-o
Anyway, I was planning to dig my old Spectrum out of storage and let my daughter see it. Are there any tips or advice that I should follow when powering up an Issue 2 48k rubberkey for the first time in 15+ years?
Would it be a good idea connect the old power supply to the mains and let it sit for a while before connecting it to the Speccy? I've brought a multimeter with me to check voltages, incase it has gone bad.
Anyway, I was planning to dig my old Spectrum out of storage and let my daughter see it. Are there any tips or advice that I should follow when powering up an Issue 2 48k rubberkey for the first time in 15+ years?
Would it be a good idea connect the old power supply to the mains and let it sit for a while before connecting it to the Speccy? I've brought a multimeter with me to check voltages, incase it has gone bad.
Post edited by Dave_C on
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Good plan MrCheese - just unpacked it to let it acclimatise. It's actually been in the box so long that the cables have 'melted' themselves into the expanded polystyrene tray! Must be due to the plasticiser chemicals used in the cable insulation. Luckily the cables look OK after picking off the white bits. :smile:
Nx
Therefore, it's always a good idea to turn on your speccies, at least one time a year, to ensure caps don't degrade.
A solution would be to open the computer and replace all electrolytic caps before applying power source, but that defintely would break the keyboard membrane. If you can see thru the rear expansion hole that the keyboard membrane is cracked, then I would replace at least the larger filter capacitors that go on the supply rails: C50 - 22uF (9V rail), C34 - 22uF (5V rail), C44 and C45 - both 100uF (12V rail) (this is for issue 3B board)
Unless a better approach is exposed, and if you don't want to open the computer, this is what I would do:
- First, take another working Spectrum and tune the TV so you can see a picture. Your Spectrum will likely send the video signal using roughly the same frequency. What we want to achieve is to get a visual response of the computer as soon it is powered on. Having a Spectrum in unknown condition turned on for seconds or minutes while searching for TV tunning could be dangerous: your computer could be damaging RAM chips as time happens, if the power rails are not ok.
- Another approach is to take a composite video signal from the Spectrum. If you have any kind of Spectrum interface (a Kempston interface for instance), you can get composite video using one of the signals available at the rear bus. This is far better than RF picture, and you won't have to bother tunning your TV.
- If possible, use a regulated 9V, 1A supply. Watch out with polarity!!!!!!
- Connect the Spectrum to the already turned on and tuned TV.
- Make sure the power supply is dircharged: with the supply removed from the mains, take a piece of wire and short circuit the two terminals of the 9V jack.
- Connect the 9V jack to the Spectrum.
- Connect the supply to the mains.
- If no picture shows up, not even a change in the "static" picture, disconnect inmediately. If using the RF output, try to use the composite video output trick.
- Assuming from now on that some kind of picture is present, there will be a brief moment, after power on, in which the border is white, and random blocks will be on the "paper" area. Then, after less than a second, the paper should turn black.
- If the paper doesn't turn black within half a second, disconnect inmediately, wait for 3-4 seconds, and turn it on again. If the paper stays "garbled", then- you are out of luck: there's something wrong inside.
- If the picture seems dimmed and a rapid sucession of "noise" happens on the screen (this can be seen better with the composite video output), then disconnect inmediately: there's a power failure in the internal DC generator (likely TR4), and could cause damage (if not already) to the lower RAM chips.
- Try to be in a quiet room when you perform these tests: a working Spectrum emits a "buzzz" sound while working, which you can clearly hear if you put you ear close to the computer. If no "buzzz" is heared just after power on, disconnect inmediately: TR4 is gone.
- If the paper turns black and doesn't turn again to the copyright message, out of lucky again: one or some lower RAM chips are gone.
I'd certainly agree with this advice. Sinclair's original PSU is of the simplest and cheapest design possible. Given that they're almost 30 years old, I'd take Miguel's advice, and replace it when you can. If you're in the UK, Maplin should stock what you need. Just make sure you get the polarity correct :-o
Nx
Unfortunately I haven't got another Spectrum, this is my original machine from back in the day. I do, however, also have a SNES in the cupboard here which I could maybe use to pre-tune the TV - any idea if this uses the same RF channel as the Speccy?
I replaced the Spectrum keyboard and membrane around 1986. It only had 1 or so years heavy use before I went 16-bit, so I'm hoping it'll still be in one piece. It certainly looks in OK condition from what I can see through the expansion slot.
If that is the case there should be no effect on internal components in a device in storage,the life span of most components are only gradually effected when current is running through them.What i was taught was that Electrolytic capacitors (the `can` shaped ones) are the easiest effected as the material in between the opposing plates (the dialectric) is effected by the constant change in temperature during use so over time the dialectric gradually looses its ability to store charge and they become inefficient.
To my knowledge the only components that could be effected over time even when not in use are erasable programmable read only memory (EPROM),collecting arcade game boards i have found corrupted data in Roms and Eproms to be a common fault on game boards that have been stored in garages and warehouses for years lol
Isn't it the same channel as a VHS recorder? Have you still got one of those?
IT'S ALIVE!!!
Tried it on the VCR channel of my Dad's Panasonic portable TV with no joy - just got a very out of tune image with what worryingly appeared to be blocks on the screen. :-o
Quickly unplugged the Speccy power, and then tried to find the fine-tuning controls on the TV - but it didn't appear to have any. WTF?!?
So, dusted off my trusty old Philips portable (which had been relocated to my sisters old room :evil:), hooked the SNES up to it and tuned a channel in. After a very quick blast of Starfox I connected up the Spectrum, nervously applied power, and voila (c) 1982 Sinclair Research Ltd.!!!! :grin::grin::grin::grin:
Let it run for a few minutes. Did the old 10 PRINT "zx spectrum rules OK" / 20 GOTO 10 trick. Changed the Border, Paper, and Ink colours, then made a few Beep commands. So far everything seems to be working OK!
Once again, thanks for all the help folks! Now, my next objective is to load up a program. But which one? (At the moment I'm thinking Manic Miner...). ;)
How do i do this?
you need to find the pinout of expansion connector, and connect composite cable to it.
You can find the pinout info here:
http://groups.google.com/group/comp.sys.sinclair/browse_thread/thread/fa21b61c484d4ac7
Or you could do Womble's Composite Video Mod, which basically bypasses the RF modulator, and takes Composite straight from the TV socket.
Good.
So it was nearly right. When my Speccies had blocks on the screen it was a sign they were very dead, glad it wasn't that.
Glad it all works OK, hope you have some fun with it. I wonder when it will go back into storage? ;)
well that is certainly easier than finding the f*cking pinout.
(I'm not being sarcastic)
Exactly, that's why I thought I'd mention it. It took about 5 minutes to do.
Better reason for alternative PSU is to feed minimum (regulated) DC voltage to the Spectrum, so that insides are heated as little as possible. Or because alternative PSU is smaller (like mobile phone adapter with DC plug that fits the Spectrum). And as others said: correct polarity!!
If you decide to open up the Spectrum, I suggest you take the opportunity to stick a cooling plate (like IC sized strip of aluminum) on top of the ULA (tiny dot of cooling paste in the middle, glue on the ends). Keeping the ULA cool is important because it's the only part of a Spectrum you can't easily replace - read: can't easily find a replacement for. So you want it to live as long as possible... :smile:
last time I checked its not in HwB !
and, IIRC, the one in schematics is not easily readable.
I just looked at the schematics here in the wos archive.
is there any reason to believe that this is actually needed?
as far as I can see the ULA is designed to run hot, and after 30 years of doing so suffer no ill effects...
- Spectrum ULA's are old, and may not have much life 'left in them'.
- Higher temperature = accelerated aging. That's a very general rule which applies to electronics & other things too, with very few exceptions (if any).
So ULA may work fine & keep doing so, but for me personally the combination of above is a no-brainer: If I want to run a Spectrum often and/or for long periods of time, I make sure to stick some sort of cooling plate on the ULA. It's enough to do that for a single ULA - one you're using. No need to mess with gear that sits in a box all the time... :-)The grey +2s I have here have this. Presumably they all left the factory like this?