Search found 2287 matches

by 1024MAK
Mon Apr 22, 2019 8:29 pm
Forum: Hardware
Topic: 5.5" B/W CRT TV - maybe composite mod?
Replies: 3
Views: 62

Re: 5.5" B/W CRT TV - maybe composite mod?

It would be helpful if you can list details of any chips used in this TV.

Mark
by 1024MAK
Mon Apr 22, 2019 8:15 pm
Forum: Hardware
Topic: 5.5" B/W CRT TV - maybe composite mod?
Replies: 3
Views: 62

Re: 5.5" B/W CRT TV - maybe composite mod?

Hi Martin It may be possible to add a composite in in place of the RF input. After all, all TVs with a RF input convert this to some kind of composite signal internally. But it will not be very easy job without a schematic of the version that you have. I’m not sure if you noticed, but the versions i...
by 1024MAK
Mon Apr 22, 2019 7:43 pm
Forum: Hardware
Topic: Composite mod done Zx81 great picture but somethkng is wrong
Replies: 14
Views: 210

Re: Composite mod done Zx81 great picture but somethkng is wrong

The transistor you used. In one of your other threads, I can see that it is marked BC108B. See no -B in photo just before this post, but yes I noticed that too. Chinese ripoff bought from eBay, AliExpress or so? I really don't understand why people save pennies on parts like this, as opposed to buy...
by 1024MAK
Mon Apr 22, 2019 1:10 am
Forum: Hardware
Topic: Composite mod done Zx81 great picture but somethkng is wrong
Replies: 14
Views: 210

Re: Composite mod done Zx81 great picture but somethkng is wrong

@RS232 Okay, I’ve studied your photos. The following points concerns me: The polarity of the electrolytic capacitor appears to be incorrect. As the existing capacitor may have been damaged, I suggest removing the existing capacitor and fitting a new one. What value of capacitor did you use? For this...
by 1024MAK
Sun Apr 21, 2019 8:46 pm
Forum: Hardware
Topic: Composite mod done Zx81 great picture but somethkng is wrong
Replies: 14
Views: 210

Re: Composite mod done Zx81 great picture but somethkng is wrong

Both the ZX81 issue 1 PCB, and the ZX81/TS1000 issue 3 PCB have component positions for a variety of different video configurations. So you will see some positions where components have not been fitted.

Mark
by 1024MAK
Sun Apr 21, 2019 6:41 pm
Forum: Hardware
Topic: Composite mod done Zx81 great picture but somethkng is wrong
Replies: 14
Views: 210

Re: Composite mod done Zx81 great picture but somethkng is wrong

What TV / monitor / display are you using? Have you tried a different TV / monitor / display? Before sticking a heatsink on the ULA, can you please take a photo of the lettering/numbering on the ULA. Is the ULA in a socket? Do you just own one ZX81? And as Andy says, which version of the composite m...
by 1024MAK
Sat Apr 20, 2019 1:06 pm
Forum: Welcome Area
Topic: Hello all from Wellington, New Zealand
Replies: 3
Views: 97

Re: Hello all from Wellington, New Zealand

Welcome on board Jochen!

:D :D :D

Hello Jochen. A warm welcome to Sinclair ZX World.

I’m glad to hear that you are enjoying the forum and finding it useful :D

Mark
by 1024MAK
Fri Apr 19, 2019 9:52 am
Forum: Welcome Area
Topic: Hello all! Nice to be here!
Replies: 4
Views: 153

Re: Hello all! Nice to be here!

Welcome on board Muttley Black!

:D :D :D

Hello Muttley Black. A warm welcome to Sinclair ZX World.

Mark
by 1024MAK
Mon Apr 15, 2019 11:55 pm
Forum: Hardware
Topic: Hot rodding the Zx81
Replies: 2
Views: 125

Re: Hot rodding the Zx81

Do you really think that we would burn you at the stake? :lol:

It’s your machine. As long as you use it and enjoy it, that’s fine with me ;)

Mark
by 1024MAK
Sun Apr 14, 2019 7:38 pm
Forum: Welcome Area
Topic: Hello from Fort Worth, TX
Replies: 2
Views: 160

Re: Hello from Fort Worth, TX

Welcome on board Glenn! :D :D :D Hello Glenn. A warm welcome to Sinclair ZX World. The 9V PSU supplied with these TS1000 / ZX81 computers is an unregulated type. So without the computer connected (‘no load’), the output voltage will be in the 12V to 16V range. This is normal. The computer will work...