Sinclair ZX80 / ZX81 / Z88 Forums

Hi,
When I start up my Spectrum +3 I get this: Has anyone had this problem and if so is it easy to fix - I have just seen a similar screen for a zx 48k and it might be ram problem?

One of the common problems with Spectrums is indeed RAM faults.

Now, there are some ROM based RAM testing programs, but you need either a expansion that can take a ROM cartridge (the device must be compatible with a +3), and a suitable ROM cartridge (new modern ROM cartridges are available), or an expansion that has a flash ROM that can be programmed with the RAM test program, or you can use a EPROM or EEPROM programmed with the RAM test program) in the ROM sockets.

The test program will test all the RAM and will display the results as coloured bars in the border area. If the RAM that contains the screen area is working, it will also print the results on the screen. You can then change the RAM chip(s) that correspond to the faulty data bits as indicated.

https://github.com/brendanalford/zx-diagnostics/wiki

http://www.fruitcake.plus.com/Sinclair/ ... ridges.htm

Alternately you could just change the four RAM chips. Start by just renewing IC3 and IC4 and then try powering on again.

Also try the self test mode, see here.

There are various copies of the service manual around, a HTML version starts here
Another is here

Mark

Thanks Mark,
I'll get my dad to check them for me as he has made stuff for me before like a plug in card for the 800XL to copy disks to cartridge chips

See edit above

Oh, before you try changing the RAM, try another Z80 CPU first. It's faster and easier to try the socketed chips first.

Mark

Super, thanks mark, I will try these

Scott

Update - now up and running (lots of chips replaced) but the Keyboard is not working at the moment - any ideas?

What is drive m?

Memory drive, basic does not use the full memory so the rest can be used as a ram.drive, I believe the same memory if free is used during a disk copy also

Regards Andy