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Photos added but I cannot open the case, it seems to be glued together and I am scared of damaging the case by forcing it.

Hi All I have been sorting through my retro computer boxes and found a cartridge that doesn't have any markings or labels on, I suspected it was for a Dragon Computer so I plugged it in to one of my dragon 32's It powered up and displays MXT I/O CONTROLLER Does anyone have any knowledge of the cartr...

Hi All, I have checked my results and noticed an error 6_____1.80 (1.73)__________35___ 1.11 (0.80) This leads to another question pin 35 output of 0.8v goes to IC33 pin 8 via IC36 pins 2 & 3 and then R83 which drops the voltage to 0.72v.? I have just checked the voltages on all the RAM chips and se...

The voltage tests on IC39 with it still fitted are : ___WORKING (FAULTY)___WORKING (FAULTY) 1_____4.56 (2.02)__________40___ 5.08 (4.87) 2_____1.59 (2.02)__________39___ 4.39 (1.01) 3_____4.56 (2.02)__________38___ 1.15 (1.34) 4_____4.56 (2.02)__________37___ 3.68 (1.03) 5_____1.56 (1.61)__________3...

Results with BASIC ROM's removed _______________Reset switch _______Working Dragon ____________________Faulty Dragon S0 (pin 25) _____not pressed ___________0.90v______________________________ 0.18v S0 (pin 25) _____held in _______________4.62v ______________________________4.43v S1 (pin 26) _____no...

Original results re-done to read more easily _______________Reset switch _______Working Dragon ____________________Faulty Dragon S0 (pin 25) _____not pressed ___________0.18v______________________________ 0.18v S0 (pin 25) _____held in _______________4.62v ______________________________4.42v S1 (pin...

The next test I did is :

Removed IC39 from both Dragons and compaired voltages on all pins of IC40 and they are the same/similar.
I now suspect that it is something else prior to IC39 that is affecting S1 and S2.
But first I will remove the IC34 & IC37 RAM chips and compair results.

Hi Sixxie & Alistair I have got myself another Dragon 64 that is working. I have done as Sixxie suggested and checked the following voltages : Reset switch Working Dragon Faulty Dragon S0 (pin 25) not pressed 0.18v 0.18v S0 (pin 25) held in 4.62v 4.42v S1 (pin 26) not 4.59v 1.3 to 2.4v fluctuating S...

Again I am showing my ignorance, it seems that by getting lazy and using pc's/Microsoft I have forgotten most of my board level computer knowledge. It is making me determined to get this knowledge back, I might even take a college/university course, if they still do them on 8 bit machines. Could you...

I tried what sixxie suggested motor on :: motor off :: sound 1,1 but nothing happening. I removed IC34 & IC37 (ram ?) and the checked board was displayed first in black/white then after a lot of screen distortion a brown/yellow checked board was displayed. Excuse my lack of knowledge but are these t...