Loading from a "tape recorder". Final test, if there's no garbage on the loading screen or artifacts in the game, it's working as it should. Finished prototype, all problems solved. It's time to send version 1.1 to production. 😎

#Sinclair #ZXSpectrum #Issue6A #RubberClone

Loading from a "tape recorder". Final test, if there's no garbage on the loading screen or artifacts in the game, it's working as it should. Finished prototype, all problems solved. It's time to send version 1.1 to production. 😎

#Sinclair #ZXSpectrum #Issue6A #RubberClone https://t.co/J0ZGQnEwTx

1/3 #Sinclair #ZXSpectrum 48k Issue6A clone update: a new membrane for the keyboard of the Polish company QWERTY. Good quality and you don't have to pay for shipping from the UK and customs/VAT.

#Speccy #RubberClone

ULA is a hot chick, erm... chip. 62°C and still rising a bit. I glued RaspberryPi heatsinks on it and the temperature dropped to 42, but then it started acting weird, so I had to take them off, hmmm... cold joint to ground?

#Sinclair #ZXSpectrum #Speccy #RubberClone

Analyzing the circuit until 3 am only to find out that for R52 I used 10k instead of 2.2k 🙃 After replacement, beautiful high contrast image. Problem solved. 2/2

#Sinclair #ZXSpectrum #RubberClone

2/2 Because I used the ZX8401/PCF1306 replacement in the socket, the case from 48k will not close, no problem in the "+" version, ... or you have to solder directly to the board.

I still have to check the beeper and audio jacks.

#Sinclair #ZXSpectrum #RubberClone https://t.co/Mtiyq4dRvp

Half a night of measurements, a few by-passes, 3 hours of sleep ... it's finally working! 🤗

#RubberClone #Sinclair #ZXSpectrum https://t.co/P9c581AE8N

Update: all voltages are now normal. I check all connections before I populate the sockets with ICs. I am a bit worried about the regular peaks in the power path: ampl. ~500mV, f ~4.7kHz, is it from a switching regulator?
#RubberClone #Sinclair #ZXSpectrum https://t.co/KmKQNHHbqe

First connection to power! 😄 No smoke... good 😅 We have beautiful +5V and +12V, but unfortunately no -5V. There is around -100mV behind the zener diode and it slowly rises towards zero... Hmmm... Now comes the fun.

#RubberClone #Sinclair #ZXSpectrum https://t.co/JElEgFVISI

muRata OKI-78SR-5/1.5-W36-C - modern DC-DC switching regulator. Found them pretty cheap locally, so I bought some. All you need to do is change the pinheader.

#ZXSpectrum #RubberClone https://t.co/MfhDis9ZXx

As the Germans say: "Langsam, aber sicher!" :) Everything almost in place... waiting for the elements of the power section.

#Sinclair #ZXSpectrum #Speccy #RubberClone https://t.co/asga41Vxkr

The prototype of the #ZXSpectrum 48K Issue 6A clone has just arrived 😁 First try-ons...

#RubberClone #Sinclair #Speccy https://t.co/6FwD8einFz

A few sleepless nights later... All tracks on the top and bottom layers are ready. My goal is complete reverse engineering (with schematic) of the #Issue6A to #KiCad.
Also, I need a good codename, I'm not sure #RubberClone sounds right 😅

#Sinclair #ZXSpectrum #ZXSpectrum40 https://t.co/SCeJQGkx4M https://t.co/k5tLlkZDBj

I finally started building my #ZXSpectrum Issue 6A motherboard clone. Take a look on these beautiful brand new blue radial Vishay capacitors. 😎

#RubberClone #Sinclair #Speccy https://t.co/WSXn5TIk2B