Search found 1257 matches

by mrtinb
Fri Sep 04, 2020 9:10 pm
Forum: Hardware
Topic: ZX81 generates high pitched sound on CRT
Replies: 28
Views: 3987

Re: ZX81 generates high pitched sound on CRT

Eagle CSS40 System CSS-14 Series, CCTV System. Monitor Model P701 (HVM29XXAS4C).

Can't find anything about it.

Sound is off, when LISTing i FAST-mode, but the resumes, when picture is drawn again.
by mrtinb
Fri Sep 04, 2020 2:59 pm
Forum: WANTED
Topic: ZX81 ULA or ULA Replacement
Replies: 12
Views: 2880

Re: ZX81 ULA or ULA Replacement

Hello again, Sorry but I couldn't get all information about it. Please to check : http://blog.retroleum.co.uk/electronics-articles/nebula-spectrum-ula-chip-replacement-module/ May it helps you? write to Phill, he will answer you properly. The price is pretty low compared with other solutions. Cheer...
by mrtinb
Fri Sep 04, 2020 1:01 pm
Forum: Hardware
Topic: ZX81 generates high pitched sound on CRT
Replies: 28
Views: 3987

Re: ZX81 generates high pitched sound on CRT

I use Andy's ULA, and often inverse the whole screen. Then it is white text on black screen. This also generates the sound. So I don't think it's related to black text on white screen.
by mrtinb
Thu Sep 03, 2020 9:51 pm
Forum: Hardware
Topic: ZX81 generates high pitched sound on CRT
Replies: 28
Views: 3987

Re: ZX81 generates high pitched sound on CRT

I the weekend I'll check if I can see some blue sparks in the dark.
by mrtinb
Thu Sep 03, 2020 9:29 pm
Forum: Hardware
Topic: ZX81 generates high pitched sound on CRT
Replies: 28
Views: 3987

Re: ZX81 generates high pitched sound on CRT

Thank you for your replies about a faulty flyback transformer. There are maybe 2 things that indicates this is not the problem: I don't know the age of the monitor, but I have just bought it, and has never been used before. I unwrapped the package. The sound does not come, when I connect a camera a ...
by mrtinb
Wed Sep 02, 2020 4:55 pm
Forum: ZX BASIC
Topic: ZX81 RAM Disk Operating System
Replies: 8
Views: 9999

Re: ZX81 RAM Disk Operating System

You can look at SIMDOS2 which is a RAM-disk for ZX81.

I use it when I need to join lines from different programs. Great software.

SimDos2
http://cd.textfiles.com/230/EMULATOR/SI ... /SIMDOS2.P

SimDos2 instructions
http://cd.textfiles.com/230/EMULATOR/SI ... OGINFO.TXT
by mrtinb
Tue Sep 01, 2020 5:25 pm
Forum: Development
Topic: Splash Scree
Replies: 10
Views: 3570

Re: Splash Scree

I think both EightyOne and other emulators support recording the screen to animated GIFs. I've used it my self to demonstrate my programs.
by mrtinb
Tue Sep 01, 2020 12:29 pm
Forum: Hardware
Topic: ZX81 generates high pitched sound on CRT
Replies: 28
Views: 3987

Re: ZX81 generates high pitched sound on CRT

I'll have no time looking into it tonight, but thank you for your replies. I'll post back in a few days.
by mrtinb
Tue Sep 01, 2020 11:45 am
Forum: Hardware
Topic: ZX81 generates high pitched sound on CRT
Replies: 28
Views: 3987

Re: ZX81 generates high pitched sound on CRT

I havn't opened up the monitor.

I don't feel so comfortable with an open monitor turned on, and sticking my head near, trying to listen, when it's turned on. I think of the high voltage of the CRT.
by mrtinb
Tue Sep 01, 2020 11:43 am
Forum: Hardware
Topic: ZX81 generates high pitched sound on CRT
Replies: 28
Views: 3987

Re: ZX81 generates high pitched sound on CRT

Well the volume is turned totally down. So I think the sound is comming from somewhere else.