Well, I’ve finally managed to get my hands on a ZX Spectrum 48k with a view to repairing it as it was listed as not outputting any type of display.
It came with the RF lead and the original PSU, as well as a couple of cassettes.
The speccy itself is actually in rather decent condition with only a couple of minor dents on the front of it.
It is dirty, again not unexpected given its age.
Inside, we can see that it is an Issue 3 board and, again, it is in pretty decent condition with no evidence of any prior work being done to it.
Unfortunately, the keyboard membrane didn’t survive me taking it apart so this will need to be replaced in the event we get it up and running.
Now the fun starts as we try and troubleshoot what the issue is. First order of business will be to do a cursory check of all the capacitors and chips to ensure that there is nothing obviously leaking, damaged or missing.
My rough list of objectives will be to:
- Test the 7805 to ensure it is supplying the correct voltage, as I understand this is a common issue
- Check the ULA – as I don’t have a diagnostic cart, initially this will probably be with a multimeter and oscilloscope
- Do a composite mod. That way I don’t need to worry about having a TV that takes the old AV input.
Leave a Reply