Spectrum 48K Upper Ram Fault
Re: Spectrum 48K Upper Ram Fault
Ha, typo - good spot!!
- 1024MAK
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- Location: Looking forward to summer in Somerset, UK...
Re: Spectrum 48K Upper Ram Fault
I was wondering, but as you said it was working...
Mark
Mark
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
Re: Spectrum 48K Upper Ram Fault
Hi Mark
Yes, all working. Thanks so much for your help and advice.
I think I know what was causing the problem too. I have two power supplies; one is a variable voltage one and the other is a Sinclair UK1400 that was faulty. As the Sinclair PS was faulty I hadn’t been using it, but I repaired it and must have used it when the speccy came back to life. When I picked up the variable voltage power supply today I noticed it was set to 12V, so I suspect I had been over doing it. I was probably lucky I didn’t do any serious damage!
It is working well on both power supplies now. I still suspect the ULA is iffy as it has a tendency to go black-and-white every so often, can crash after a while if I don’t have a heat sink on it, and the diagnostic tests regularly tell me the ULA is faulty. I’ll probably get a new one but I didn’t want to spend the money unless I had sorted the RAM out, and that seems to be ok now.
Cheers!
Yes, all working. Thanks so much for your help and advice.
I think I know what was causing the problem too. I have two power supplies; one is a variable voltage one and the other is a Sinclair UK1400 that was faulty. As the Sinclair PS was faulty I hadn’t been using it, but I repaired it and must have used it when the speccy came back to life. When I picked up the variable voltage power supply today I noticed it was set to 12V, so I suspect I had been over doing it. I was probably lucky I didn’t do any serious damage!
It is working well on both power supplies now. I still suspect the ULA is iffy as it has a tendency to go black-and-white every so often, can crash after a while if I don’t have a heat sink on it, and the diagnostic tests regularly tell me the ULA is faulty. I’ll probably get a new one but I didn’t want to spend the money unless I had sorted the RAM out, and that seems to be ok now.
Cheers!