22 Oct
2001
22 Oct
'01
11:41 a.m.
Tony Duell skrev:
> So I find this nice little program called
"Toot", which "toots" Spectrum
> snapshots into the earphone socket of said machine.
I assume this involve a direct connection from a PC
soundcard to the
Speccy. Do you know if your PC is properly grounded? Do you know if
either side of the Speccy PSU is grounded? Could you have shorted
something out (or worse, applied half mains voltage across the Spectrum)
via the ground connections
Actually, it would involve an Amiga, no PC. =)
The Amiga is routed through a "sound enhancer" (some filters to make the sound
crisper) into an amplifier, and the tape output of the amplifier would go into
the Speccy earsocket.
Only I never got that far. The Speccy started smelling before I ever got as
far as tuning into its RF signal or plugging it into the stereo.
> What happens when I plug the machine in? A hideous
smell, that's what. Now
> I'm back at square one. No working Speccy. All I get is a black screen.
> When fine- tuning the receiver, the border is sometimes visible. Is there
> something irreplacable, like the ULA, which has broken, or is it the CPU
> (I've got plenty of those) or just some discrete component?
The most common problem (or so I am told) on early
Spectrums is the
transistor in the PSU converter circuit. It generates at least one of the
supply lines for the DRAM. I would start by checking the power supply
voltages at the DRAM pins.
Thank you, I'll do that as soon as I get to a multimeter.
It's rather nice that the system is so simple that there isn't a whole lot of
modules with various dependencies which may fail resulting in different
behaviours.
--
En ligne avec Thor 2.6a.
You can have SEX with a Dragon but not with an Apple.
-- Tony Duell