exxos's Atari, Amiga & retro forum

I am not sure where I got this from but whilst I was going through all my Sinclair kit (mostly QL / QIMSI Gold update) I found a ZX Spectrum+ which wasn't working.

This model is a Spectrum+ upgrade where the original issue two motherboard which looks like an original 48K board was taken out of a rubber keyed spectrum and placed in the plus case. I am sure I know the name of the person that did this as I have the original box / poly with the original shipping address on it :). If you happen to be reading this and you had a ZX Spectrum+ back in the day in Witham, Essex feel free to ping here :)

From the outside it looked pretty clean

However it was in a sorry state as the keyboard membrane ribbon was torn


And at power up I get black and white vertical lines and garbage on the screen so got hold of a diagnostics board to do checks and its says both lower and higher ram is failing although I have noticed the -5V is not lighting up on the diagnostics board which is used by the ram. Its had a few patches on the board already (diode / resistor fix instead of the spider transistor fix).


So in an effort to bring this back to life I have ordered a few parts to sort out the power area and also some RAM chips in case they are fried. I intend to get this working and then drop in the vLA82S+ Spectrum ULA Replacement with RGB interface and AY Emulator. All my other Spectrums are stock and thought as this is an upgrade re plus case I would upgrade it further.

Forgot to add already done the first upgrade of replacing the original voltage regulator and heatsink with a Traco TSR1-2450

So, TR4 dead then?

I’d replace all the lower RAM 4116s with hacked 4164 or 41256 chips and make the system more efficient

stephen_usher wrote: 25 Sep 2025 19:17 So, TR4 dead then?

I’d replace all the lower RAM 4116s with hacked 4164 or 41256 chips and make the system more efficient

Thanks @stephen_usher, I ended up going with a modern SRAM module which also doesnt use the -5V line.

Lower RAM chips removed this morning. Am thinking of socketing all the chips to make things easier in the future, although not looking forward to desoldering the Z80

Icky wrote: 26 Sep 2025 14:40 Lower RAM chips removed this morning. Am thinking of socketing all the chips to make things easier in the future, although not looking forward to desoldering the Z80

Bah, you know you want to: you've already done more pins with the combined RAM extraction!

BW

Badwolf wrote: 26 Sep 2025 15:12 Bah, you know you want to: you've already done more pins with the combined RAM extraction!

But the lower ram removal was a bit more brutal clipping out stubborn legs. :)

Icky wrote: 26 Sep 2025 15:28

Badwolf wrote: 26 Sep 2025 15:12 Bah, you know you want to: you've already done more pins with the combined RAM extraction!

But the lower ram removal was a bit more brutal clipping out stubborn legs. :)

Further cowardice, you say?!

:lol:

BW

Icky wrote: 26 Sep 2025 15:28

Badwolf wrote: 26 Sep 2025 15:12 Bah, you know you want to: you've already done more pins with the combined RAM extraction!

But the lower ram removal was a bit more brutal clipping out stubborn legs. :)

They wouldn't come out even with flux and hot air?

Why do you need the Z80 removed anyway?

stephen_usher wrote: 26 Sep 2025 16:13 They wouldn't come out even with flux and hot air?

I was being lazy and didn't have my hot air gun to hand.

stephen_usher wrote: 26 Sep 2025 16:13 Why do you need the Z80 removed anyway?

Just because :) - thought I would have this board with all ICs socketed incase I want to play around with things.