Thread: Zx81
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Old 23rd Mar 2020, 12:44 am   #136
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
Posts: 8,621
Default Re: Zx81

I think maybe we are getting diode and transistor confused again, did you mean that it is the transistor which is getting hot? (Not the diode, which you don't seem to have fitted yet).

Edit: Just got your update. Well, the transistor is between +5V and 0V with quite a low resistance (100R) in series, and that 100R is in parallel with the likely 75R input resistance of the composite-in input on your display, so yes, it would not surprise me if it ran warm. But if so, there is another target for your freezer spray once the fault appears - spray the transistor as well.
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