+3 Verticle Black & White Lines
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+3 Verticle Black & White Lines
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?
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?
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- 1024MAK
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Re: +3 Verticle Black & White Lines
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
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
Last edited by 1024MAK on Sun Mar 27, 2016 12:31 pm, edited 1 time in total.
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
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- Posts: 10
- Joined: Sat Mar 26, 2016 2:47 pm
Re: +3 Verticle Black & White Lines
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
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
- 1024MAK
- Posts: 5103
- Joined: Mon Sep 26, 2011 10:56 am
- Location: Looking forward to summer in Somerset, UK...
Re: +3 Verticle Black & White Lines
See edit above
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
- 1024MAK
- Posts: 5103
- Joined: Mon Sep 26, 2011 10:56 am
- Location: Looking forward to summer in Somerset, UK...
Re: +3 Verticle Black & White Lines
Oh, before you try changing the RAM, try another Z80 CPU first. It's faster and easier to try the socketed chips first.
Mark
Mark
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
-
- Posts: 10
- Joined: Sat Mar 26, 2016 2:47 pm
Re: +3 Verticle Black & White Lines
Super, thanks mark, I will try these
Scott
Scott
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- Joined: Sat Mar 26, 2016 2:47 pm
Re: +3 Verticle Black & White Lines
Update - now up and running (lots of chips replaced) but the Keyboard is not working at the moment - any ideas?
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- Posts: 10
- Joined: Sat Mar 26, 2016 2:47 pm
Re: +3 Verticle Black & White Lines
What is drive m?
Re: +3 Verticle Black & White Lines
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
Regards Andy
what's that Smell.... smells like fresh flux and solder fumes...