Another disadvantage of sockets is that they add extra parasitic effects on the signals, which may become a problem when running the system at 4 GHz for higher fps...
Today I found out that the NES games "Solar Jetman"(which I loved as a kid) is actually the 3rd in the series, where Jetpac and Lunar Jetman where the number 1 and 2 and both ZX spectrum games.
Love these quick fix videos. Maybe I've been lucky but I've tried the earlier Speccy's with LCD and plasma TVs and the image was better than a portable CRT.
Thanks Captain! I think the one I'm using as a test screen is just not very good. My old one was great, smaller and better picture. But that one developed a fault where the earth shielding on it was at 100v 😱
no need to disconnect the 2 modulator leads to composite mod it, you can even leave the resistor connected to get 'simultaneous' rf and composite out .. also reducing the emitter resistor of the modulator drive transistor by half can improve negative going parts of the signal as for recapping, i dont generally hold with 'blanket' recapping, its mostly unnecessary, they last better and longer than many think, dried up reset cap can cause a 'no start' issue, dried up c46 can result in fried lower ram, so i'd replace those first , maybe fit a non electrolytic instead, so should last 'forever'..
My guess is C27 was the bugger here. This capacitor is part of the reset circuit which holds the RESET line low on power up as it charges. If it charges up too fast (due to decreased capacitance) or doesnt charge up at all, the system doesnt get reset properly.
I think you described exactly what was happening here. Other than that things seemed functional. The dcdc was working as expected, just wasn't starting up every time.
How I laughed ... "That is odd ... so is your face!" Another cracking video showing that even the best of the best are always learning and refining their techniques. Everyone's human and most of us have odd faces.
Nice video and interesting to see a fault like that caused by dodgy caps. Its actually making me wonder about a system I'm trying to repair at present with odd behaviour, its not a spectrum but its got plenty of old caps on there...
Great video. I have an old 48k wonder under the bed that last time I tested it (about 10 years ago!) It had very wobbly video out so I think it's due a recap, so got the ZXrenew kit that I need to install and do the comp mod, so your video is a nice reminder to do that! Nice tip on heating a blob to extract from the top.
Just so you know, shorting the output of a 7805 to ground shouldnt kill it. They have internal short circuit protection, so they should just shut down. The voltage converter circuit may not like it though as it uses the 5V line as a reference voltage
Can you do a video on reducing jail bars on a 48k Spectrum please ? I repaired one once and no matter what I did to it (all new caps, composite mod) it had terrible jail bars.
@@MoreFunMakingIt Thank you for the spectrum measuring video link I will bookmark that one, perhaps you should bring it up to date with less stiff upper lip ness ? also add waveforms from the scope
