Sinclair ZX80 / ZX81 / Z88 Forums

Even with a composite mod the top line still does the slanty thing when using a 2C158 ULA if it did it when using the RF output in my experience, even Pokemon's video boards didn't cure it.

Hi Didier, is it possible to tell us which ULA you have fitted? The early 2C158 version was known to cause a bending of the first line once it got hot, I had 3 which did exactly that even with a composite video board fitted and I found a change to either a later ULA ( 2C184 or 2C210) or modern repla...

In an earlier post I said that when using my logistic equation program, that the Big Bang ROM was throwing up incorrect results. After much online calculator checking plus various maths web sites it now appears that it is the Sinclair ROM maths routines that are erroneous in this regard and in fact ...

Great to hear you have had some success at last, long may it continue!

Tried the ZXPAND command as follows..

ZXPAND "DELETE TF79.P" and it worked just fine (I did restore TF79 later!)

I used v 1.40 of EIGHTY one with the 66x2c ROM and whilst it works the CONFIG "X" command caused a crash. I haven't tried the other ROM in a later version of Eighty One as I'm only interested in real kit but would assume that the72x2c would work the same way with a later copy of the emulator.

As promised I have programmed a 2764 EPROM, fitted it to one of my classic spands and yes it works just as it should even the CONFIG "X" command works unlike when I tried it in Eighty One. So yes works OK and especially useful to owners of issue 3 computers where the ROM is usually soldered to the b...

If you don't wish to remove the socket you could at least try re-flowing the solder joints. some of the pins make contact on the top side of the board so perhaps check and see if these look solid. In my own actual experience with the ROM socket I always ended up either replacing or soldering the chi...

I once read somewhere that Memotech RAM modules needed a certain DIP switch setting to work with the Alphacom but cannot swear to the truthfulness of it,Sinclair's module should be OK though. The Alphacoms are generally very robust and as the self test is producing actualprint then I would say the a...

Found the solution! v72x2c causes the garbage for me in Eighty One but v66x2c works however CONFIG "X" causes a whiteout, I tested it to see if the "PAUSE" stutter was present after a screenful of CHR$ was SCROLLED and no stutter present and the CLS cleared the screen instantly so looks like the imp...