Spectrum Computing

Latest update: So i replaced TR4 and now yes there is color in the image and first time it booted into normal sinclair screen but after some seconds started beeping and went to black center with some red stripes in the top of the square. I had the lower ram board plugged in. Now i removed the ram bo...

So yeah, TR4 is dead as it seems.
Ordered and waiting for new to arrive and then the saga continues, just hope i did not fry the new ram module board....

Updated info for the next steps: So, the +12V and -5V are not working. Without a +12V supply, the video will only be monochrome. It's likely that TR4 and maybe TR5 are damaged. But do not remove them yet. Before hunting for other non-power supply problems, the power rails need sorting out. ---------...

Update: Following kind Marc instructions i have: Measurements (without ram board plugged in): Across C50 -> 11.83v Across C34 -> 5.01v Across C44 -> 1.92v Across C45 -> 1.89v Across C79 -> 0v Went further if would be useful: Across C80 -> 9.90v Across C46 -> 11.56v Across C74 -> -0.17v Across C27 ->...

It's no good hiding here as well as posting elsewhere! I'll still find you! Okay, best not to do anything else until I've had a chance to think about this... You say you have a digital multimeter, do you know how to measure resistance, continuity and voltages? Mark Hello Mark I have replied to you ...

Just to be clear, you put a 4116 in with the wrong orientation, then powered up? That would have connected +12V through that IC and to goodness knows where. You might have fried part of the ULA. Is the ULA socketed? Do you have a working Spectrum you can raid for test parts? You should probably sta...

Hello everyone! So here is my call for help and kindly ask if people can help me find and solve whatever problem i created. For starters i have a very basic understanding of electronics but still trying to figure things out; then i bought the basic tools to try to help finding the problem: digital m...

Hello all

Here i am as a proud owner of a zx spectrum issue 4B that i have since 1984.
Taken from storage some months ago and was working fine until i one day forgot the "if aint broken dont fix it".....
Happy 2024 to all!