Search found 107 matches

by McKlaud
Thu Apr 19, 2018 10:55 am
Forum: Welcome Area
Topic: Hello from Canada
Replies: 15
Views: 269

Re: Hello from Canada

Any unregulated PSU gives you more voltage than its rated voltage if the load is lower that the nominal load. Make the story shorty, it is uncommon that the ZX81 PSU gives approx. 10.5V when connected to the ZX81. In idle (no load connected) the PSU output voltage can reach 14.5V easily. Bear in min...
by McKlaud
Mon Apr 16, 2018 7:41 am
Forum: Development
Topic: ZX81 ULA-in-a-CPLD
Replies: 147
Views: 12186

Re: ZX81 ULA-in-a-CPLD

Nice and good to hear from you that you made some progress. My unit is in a storage box waiting till I will be back home in a few weeks.

BTW do you have the barebone 32K RAM on your testing PCB?
by McKlaud
Mon Apr 16, 2018 7:30 am
Forum: Hardware
Topic: Sinclair 128k ZX Spectrum +2 Grey UK no video after inverted polarity
Replies: 10
Views: 198

Re: Sinclair 128k ZX Spectrum +2 Grey UK no video after inverted polarity

Have a look and measure a supplying voltage to TEA200 chip. The PAL encoder requires 12V supply (pin 11 on it).
by McKlaud
Mon Apr 16, 2018 7:24 am
Forum: Welcome Area
Topic: Hello from Canada
Replies: 15
Views: 269

Re: Hello from Canada

On the output should be +5V +/- 0.25V. Anything above +5.25V means that something is wrong the voltage regulator chip. Take it out and measure a resistance between GND (middle soldering point of this chip) and +5V rail (right soldering point). The reading should be in low kiloohms but definitely mor...
by McKlaud
Sun Apr 15, 2018 7:13 pm
Forum: Welcome Area
Topic: Hello from Canada
Replies: 15
Views: 269

Re: Hello from Canada

Hi Ogien, Good that you joined us on here. I have attached a picture of the 1st broken RAM pack (48K) There is one IC on there that gets very hot quickly on it which I circled. Not sure if that is the problem but in my limited experience very hot ICs are usually not good. This pointed IC is a voltag...
by McKlaud
Fri Apr 13, 2018 9:13 pm
Forum: Development
Topic: New game - BiggOil
Replies: 6
Views: 252

Re: New game - BiggOil

Well done! I enjoy it and it is addictive. :)

Some annoying flickering when I unroll the pipe horizontally. I run the game under the ZXSP Emulator.
by McKlaud
Thu Apr 12, 2018 8:51 am
Forum: Hardware
Topic: TZXduino
Replies: 2
Views: 125

Re: TZXduino

Hi Bill, TXZduino works with p. files out of the box, if the firmware is in version 1.3 or above. I know this as the fact, because I use it in that way. Maybe the f/w needs an update. See there: http://arduitape.blogspot.co.uk/2017/03/zx81-p-and-o-filetype-added-to-tzxduino.html?m=1 :geek: From whom...
by McKlaud
Mon Apr 09, 2018 9:02 am
Forum: Hardware
Topic: 28C64 in 2364 socket (28 pin to 26 pin)
Replies: 6
Views: 212

Re: 28C64 in 2364 socket (28 pin to 26 pin)

Burn before soldering. :)

The space inside the Zeddy's case is very limited. Unfortunately you will not be able to fit your adapter there and close the case.