Part 4 – Broken Components including The Electrolytic Capacitors and Power Circuit
A common problem in old electronics is that electrolytic capacitors can fail. Age, storage conditions, usage patterns, heat and other factors can mean that they can dry out and deteriorate from their function of storing charge. This can impact on the performance of other components in the Spectrum, and even stop it from working completely.
Of particular concern inside the Sinclair-era models of Spectrum is the DC-DC conversion power circuit on the right-hand-side of the PCB in the photo above. This power circuit is notoriously unreliable and has caused many repairs to be done. It has also damaged other components, such as the lower RAM chips that are required for the system to start successfully to the Sinclair Research prompt.
The power circuit was revised and revised again in later issues of Spectrum PCB. When Amstrad took over the Sinclair brand, it was removed completely from the Spectrum PCB and put in an external PSU.
This wise decision by Amstrad did not solve all of the issues in the later models of Spectrum, but it solved some of the problems on the computer PCB. I have other articles on this website about the models of Spectrum and a whole series of article about the PSUs. I also sell all models of Spectrum and PSUs in the PopeyMon shop.
Why have I mentioned the power circuit in relation to the electrolytic capacitors? Because the power circuit is essential to the operation of the booting of the Spectrum. If the power circuit is not producing the correct voltages, then your Spectrum will not start up properly, if it starts up at all.
So if the capacitors in the power circuit are failing, then this can mean that the power circuit is not working correctly and your Spectrum fails. It can damage components that are particularly difficult to replace.
It is therefore wise to perform checks before starting up a Spectrum. I can perform these checks and more for you, when you send me your Spectrum.
I offer a service to replace all electrolytic capacitors with brand new and quality new ones – click here. While this may not fix all types of problems, it can prevent some problems from occurring now and in the future.