Search found 42 matches
- Sun Jul 12, 2020 9:33 pm
- Forum: Hardware
- Topic: 16K Issue TWO --> Hard reset when loading games
- Replies: 4
- Views: 667
Re: 16K Issue TWO --> Hard reset when loading games
Hi Both Thank you for your detailed responses. Mark, the command returns the correct result for a 16K machine. The reason I checked the ULA is I know I damaged a pad when I desocketed it, so I totally removed it (good practice) to find that it works, and it also allowed me to properly repair the tra...
- Sat Jul 11, 2020 10:35 pm
- Forum: Hardware
- Topic: 16K Issue TWO --> Hard reset when loading games
- Replies: 4
- Views: 667
16K Issue TWO --> Hard reset when loading games
Hi everyone Hoping you can help me solve an issue. I think it's a hardware issue but I'm not sure at this point. I've been refurbishing an issue two, jobs performed: Recap DCDC Mod (following Retroleum's instructions) New membrane Desocket and heatsink for ULA I know the ULA works as I tried it in a...
- Tue Jun 16, 2020 10:40 pm
- Forum: Programming
- Topic: String handling
- Replies: 0
- Views: 422
String handling
Hi I have an example script I'm modifying, and I'd like find a faster way to achieve this... DEF FN m$(q$)=q$(2 TO )+q$(1) The purpose of the function is shift a line of space invaders along by one cell, moving the last back to the front of the line. It's just so slow the game really isn't much fun!
- Fri May 29, 2020 12:35 am
- Forum: Hardware
- Topic: Spectrum 48k not booting to sinclair logo screen
- Replies: 10
- Views: 1796
Re: Spectrum 48k not booting to sinclair logo screen
Any photos of the board and its chips?
Do the pixels move while it's on or is it frozen?
Do the pixels move while it's on or is it frozen?
- Sun May 17, 2020 9:04 pm
- Forum: Hardware
- Topic: Issue 3 - Recap + DCDC Mod
- Replies: 0
- Views: 428
Issue 3 - Recap + DCDC Mod
Recapping, Composite mod, cleaning up and DCDC Modding an Issue 3, while drinking coffee.
Please tell me if you see any mistakes or inaccurate information
https://www.youtube.com/watch?v=AbIJza7 ... qz0PFOw0V0
Please tell me if you see any mistakes or inaccurate information
https://www.youtube.com/watch?v=AbIJza7 ... qz0PFOw0V0
- Sat May 16, 2020 1:19 am
- Forum: Hardware
- Topic: Stuck with repair of Spectrum+
- Replies: 76
- Views: 10399
Re: Stuck with repair of Spectrum+
Your clip of the machine running with no RAM looks a lot like what I had here https://youtu.be/OYsv7Jaseu8?t=326 That came down to a broken trace under the RAM sockets. Have you checked continuity on all the lower RAM pins (Except Din and Dout) between the farthest left (IC13) and the farthest right...
- Fri May 15, 2020 7:05 pm
- Forum: Hardware
- Topic: Another eBay gamble
- Replies: 5
- Views: 947
Re: Another eBay gamble
A small update for you. - I cleaned the case and keyboard - Did the initial tests, all OK - Plugged it in, heard the whine, OK - Checked voltages, 12V is 12.7V but generally OK, better than expected - Plugged it into my TV...... https://i.postimg.cc/bGdxsmxG/1.jpg https://i.postimg.cc/y3CcpBw9/2.jpg
- Thu May 14, 2020 10:07 pm
- Forum: Hardware
- Topic: Another eBay gamble
- Replies: 5
- Views: 947
Re: Another eBay gamble
Honestly I don't think there's a whole lot to do as long as nothing too weird is happening with the electronics. I would love to restore the face plate, but what can I do except try to paint the areas that have flaked off? I wouldn't be able to match the colour and I don't know any methods to print...
- Wed May 13, 2020 10:32 pm
- Forum: Hardware
- Topic: Another eBay gamble
- Replies: 5
- Views: 947
Re: Another eBay gamble
Honestly I don't think there's a whole lot to do as long as nothing too weird is happening with the electronics. I would love to restore the face plate, but what can I do except try to paint the areas that have flaked off? I wouldn't be able to match the colour and I don't know any methods to print ...
- Wed May 13, 2020 7:13 pm
- Forum: Hardware
- Topic: Another eBay gamble
- Replies: 5
- Views: 947
Another eBay gamble
I think I got lucky with this one!
It looks in really good shape except for the face plate.
Haven't done any checks yet... just a first looksee
https://youtu.be/RHPBncMMBpM
It looks in really good shape except for the face plate.
Haven't done any checks yet... just a first looksee
https://youtu.be/RHPBncMMBpM
- Wed May 13, 2020 10:17 am
- Forum: Hardware
- Topic: ZX Spectrum 48k reboot loop
- Replies: 10
- Views: 1648
Re: ZX Spectrum 48k reboot loop
How did you disable upper RAM?
- Wed May 13, 2020 12:08 am
- Forum: Hardware
- Topic: ZX Spectrum stuck before Sinclair copyright message.
- Replies: 51
- Views: 10563
Re: ZX Spectrum stuck before Sinclair copyright message.
How useful would be if i had an oscilloscope in this specific situation? You could check the power rails and determine if there’s too much ripple on each. You could also examine digital signals and see if there are any irregularities. A data analyzer would be even more useful. This was my thought a...
- Fri May 08, 2020 5:57 pm
- Forum: Hardware
- Topic: Issue 6A repair vlog
- Replies: 0
- Views: 440
Issue 6A repair vlog
https://youtu.be/OYsv7Jaseu8
Hi all.
This is the repair I've been posting about in another thread.
Quite an interesting, but in the end easy job.
Enjoy. Please let me know if I say anything incorrect.
4K should be processed and ready later
Cheers
Hi all.
This is the repair I've been posting about in another thread.
Quite an interesting, but in the end easy job.
Enjoy. Please let me know if I say anything incorrect.
4K should be processed and ready later
Cheers
- Wed May 06, 2020 6:16 pm
- Forum: Hardware
- Topic: Disabling Upper RAM
- Replies: 28
- Views: 4475
Re: Disabling Upper RAM
The copper tape repair went beautifully, I captured it with the microscope and the spectrum now boots correctly
- Wed May 06, 2020 4:35 pm
- Forum: Hardware
- Topic: Disabling Upper RAM
- Replies: 28
- Views: 4475
Re: Disabling Upper RAM
Thanks Mark.
Yes I'm a bit concerned about the heat gun. No problems so far but I find it a bit unrefined when the board gets a bit wobbly with the heat
Yes I'm a bit concerned about the heat gun. No problems so far but I find it a bit unrefined when the board gets a bit wobbly with the heat
- Wed May 06, 2020 2:53 pm
- Forum: Hardware
- Topic: Disabling Upper RAM
- Replies: 28
- Views: 4475
Re: Disabling Upper RAM
https://i.postimg.cc/JGMKrhjg/signal-attachment-2020-05-06-092515.jpg For you feel better pleasure. Top side just had a few traces, bottom was a disaster ground. I did the full nuke on removing all the upper ram and logic chips and for some reason that section gave me all the trouble (ram). Rest wa...
- Tue May 05, 2020 1:20 pm
- Forum: Hardware
- Topic: Disabling Upper RAM
- Replies: 28
- Views: 4475
Re: Disabling Upper RAM
I've never used it before but it seems like a good solution, fingers crossed, if I make a mess again it's going to get harder to fix
- Tue May 05, 2020 11:00 am
- Forum: Hardware
- Topic: Disabling Upper RAM
- Replies: 28
- Views: 4475
Re: Disabling Upper RAM
Time to put it away until the copper tape arrives... Copper tape? You mean the desoldering stuff? No it's a sticky copper tape for electronic repairs. You tidy up the damage, stick this over and solder it in. I tried to make the link with a small wire but buggered it up https://i.postimg.cc/y3dHvsn...
- Mon May 04, 2020 8:04 pm
- Forum: Hardware
- Topic: Disabling Upper RAM
- Replies: 28
- Views: 4475
- Mon May 04, 2020 11:39 am
- Forum: Hardware
- Topic: Disabling Upper RAM
- Replies: 28
- Views: 4475
Re: Disabling Upper RAM
My replacement Z80 was actually a Z84C20 with is a PIO chip. What, and it didn't work? :lol: I'm impressed that anything happened. I got the screen shown in the post above and the blocks were changing. The chip did get quite hot though... It got me thinking, could you make a simulation so accurate ...
- Sun May 03, 2020 9:31 pm
- Forum: Hardware
- Topic: Disabling Upper RAM
- Replies: 28
- Views: 4475
Re: Disabling Upper RAM
It looks like a bad joint on the topside of the board as there is continuity from the socket to the underside
- Sun May 03, 2020 9:02 pm
- Forum: Hardware
- Topic: Disabling Upper RAM
- Replies: 28
- Views: 4475
Re: Disabling Upper RAM
Hi! Sorry, I like to share, I hope it's interesting. After reading some of the Z80 Technical Manual (Great little book happy to have found it) I realised a silly mistake. My replacement Z80 was actually a Z84C20 with is a PIO chip. I put an actual Z80 in and got a white border with some more familia...
- Sun May 03, 2020 2:38 am
- Forum: Hardware
- Topic: Disabling Upper RAM
- Replies: 28
- Views: 4475
Re: Disabling Upper RAM
C80 - should be 22uF, was 1uF - :shock: this will affect the power output of the DC/DC converter :-( C74 - should be 4.7uF, was 22uF - :shock: this will affect the response time of the regulation of the +12V line :-( C27 - should be 1uF, was 4.7uF - that will just give a slightly longer reset pulse...
- Sun May 03, 2020 12:16 am
- Forum: Hardware
- Topic: Disabling Upper RAM
- Replies: 28
- Views: 4475
Re: Disabling Upper RAM
Slight diversion from the original thread but I just noticed that whoever recapped this board used the wrong rating of capacitor in a few locations. ........might be a good place to start! Different capacitance? Different voltage? Higher value? Lower value? In most applications, the next value up, ...
- Sat May 02, 2020 7:05 pm
- Forum: Hardware
- Topic: Disabling Upper RAM
- Replies: 28
- Views: 4475
Re: Disabling Upper RAM
Slight diversion from the original thread but I just noticed that whoever recapped this board used the wrong rating of capacitor in a few locations.
........might be a good place to start!
........might be a good place to start!