Search found 463 matches

by Cristian
Sun Feb 11, 2018 1:00 pm
Forum: Hardware
Topic: QL Mainboard Power Connector
Replies: 9
Views: 870

Re: QL Mainboard Power Connector

And what about the plugs? Are they available?
by Cristian
Tue Feb 06, 2018 10:22 am
Forum: Hardware
Topic: All RAM chips destroyed??
Replies: 62
Views: 4693

Re: All RAM chips destroyed??

Dave wrote: repeat the loop until you get to the end (it boots properly, or you run out of chips to replace)....

I'm just waiting for 15 new Dram chips... let's hope they are enough :mrgreen:
by Cristian
Mon Feb 05, 2018 7:37 pm
Forum: Hardware
Topic: Naive question about SCART connection on TV
Replies: 56
Views: 3881

Re: Naive question about SCART connection on TV

Eureka!
by Cristian
Sun Feb 04, 2018 9:32 pm
Forum: Hardware
Topic: All RAM chips destroyed??
Replies: 62
Views: 4693

Re: All RAM chips destroyed??

it does seem likely that one further RAM chip replacement is worth the effort. I'm afraid the title of this topic is very close to the truth :mrgreen: It was your efforts and the conversation in this thread that prompted me to explore a bit more deeply - thanks for that! I could say the same! I thi...
by Cristian
Sat Feb 03, 2018 5:55 pm
Forum: Hardware
Topic: All RAM chips destroyed??
Replies: 62
Views: 4693

Re: All RAM chips destroyed??

I've just replaced a RAM (IC7) and things seem to go a little better... this is the sequence: 1) the stipple pattern seems to cover the whole screen (finally!); 2) a Minerva error code appears for a very short instant; 3) the Minerva logo appears; 4) a pattern of thin vertical green lines appears an...
by Cristian
Fri Feb 02, 2018 8:31 am
Forum: Hardware
Topic: All RAM chips destroyed??
Replies: 62
Views: 4693

Re: All RAM chips destroyed??

tofro wrote:Minerva RAM test prints:
  • Value written
  • Value read back
  • Address


Thank you. So I entered correctly the values, and the faulty Ram to be replaced is IC7
by Cristian
Thu Feb 01, 2018 7:33 pm
Forum: Hardware
Topic: All RAM chips destroyed??
Replies: 62
Views: 4693

Re: All RAM chips destroyed??

The piggy back method may not work in this case either. The more I investigate this case, the more I feel it's "simply" a RAM issue. I've just done a new test with Minerva Rom installed. I ran Ramtest_bas and entered the values. Which is the address value? The last one in the triplets? In...
by Cristian
Thu Feb 01, 2018 1:14 pm
Forum: Hardware
Topic: All RAM chips destroyed??
Replies: 62
Views: 4693

Re: All RAM chips destroyed??

1) R70, between 8301 and oscillator. Are you suggesting me to measure someone else? 3) OK, here my ignorance is greater, so to be sure I'll replace the MGI roms 5) yes, it still works :-) 7) in any case, I tried to swap also the PAL encoders 8) Yes sure, it would be the last desperate option To be p...
by Cristian
Thu Feb 01, 2018 12:30 pm
Forum: Hardware
Topic: All RAM chips destroyed??
Replies: 62
Views: 4693

Re: All RAM chips destroyed??

Thanks for your informatiion Rich, but fortunately my 8301 seems OK. I swapped it with other good QL and it works. The minor problem of the grayscale UHF output should be related to the oscillator or IC28 (this might explain why IC28 gets got). The main problem (white screen) remains. So, as next st...
by Cristian
Wed Jan 31, 2018 6:37 pm
Forum: Hardware
Topic: All RAM chips destroyed??
Replies: 62
Views: 4693

Re: All RAM chips destroyed??

Not sure which ULA you're now speaking about, but presume you mean the ZX8301 :-) Yes you’re right I used a shorter (but unprofessional) term to indicate zx8301. So: 1) the resistor looks better in the reality than in photo. I measured it and the resistance matches. 2) I removed zx8302. Result: bla...

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