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non standard loader bar coloursAs with my speedloader thread, when did non standard colours start to appear and who came up with the idea and what was the reaction?
... , intensive writing to the lower 16K RAM may cause timing problems due ... I was assembling it into lower RAM. -
BooHoo....Broken Speccy on 25th anniversary!Speccy broke today (today of all days!!) I'm presented with black screen on power up, anybody any ideas what might have gone wrong and any repair ti…
Almost certainly a bad 4116 lower RAM chip.
Repair means ... -
Reason for strange display layout?I have always wondered if there is any technical reason behind the strange layout of the display file or why did Sinclair choose to do it this way?
... required much more contention for lower RAM with the Spectrum's simple ... the screen picture read the RAM only when the CPU didn ... given that the slowest static RAM today has an access time ... -
48K Speccy not workingHey, A few months ago (hope it´s not to late) I was loading a game into my speccy and from one moment to another it stopped working! I unplugge…
... to check (once again) the lower RAM voltages, because a common component ... have dead lower memory (according to the TMS4116 datasheet, 4116 RAM will ... -
48K Speccy not workingHey, A few months ago (hope it´s not to late) I was loading a game into my speccy and from one moment to another it stopped working! I unplugge…
... /> ULA, Z80, power supply transistors, lower RAM and tr8, tr9 transistors were ... -
Running code from the display memory?Is it possible to run machine code from the memory area used by the display file? If you were really out of memory and some part of screen is not u…
Each 3rd of the screen provides 2Kb of memory (and an additional 256 bytes if you include the attributes area).
Nice one Icabod, it never occurred to me though of the fact that the lower RAM isn't contended during the border trace! -
Unconventional way of diagnosing a faultHi everyone Some time ago I got a 48k Spectrum (issue 3B board) in a pretty bad condition. I believe the power supply transistor TR4 failed, causing…
... the only fault is lower RAM, it's unlikely you ... can think of where lower RAM has failed in such ...
Since the 4116 RAM would have likely been damaged ... desolder all the 4116 RAM and put them in ... be fully functional and lower RAM can be completely goosed.< ... -
Unconventional way of diagnosing a faultHi everyone Some time ago I got a 48k Spectrum (issue 3B board) in a pretty bad condition. I believe the power supply transistor TR4 failed, causing…
... I can think of where lower RAM has failed in such a ... />
[QUOTE]Since the 4116 RAM would have likely been damaged ... would desolder all the 4116 RAM and put them in sockets ... 't be fully functional and lower RAM can be completely goosed.[/QUOTE ... -
UlaI remplaced an ULA 6c001-6 by an ULA 6c001-7 chip on issue 3B board. It is "crucial" to remove R32 and adding the 2x NAND gates ??? or not ? Thanks.
Not really, they get used plenty anyway - whenever lower RAM is accessed (so regularly by the ULA) -
UlaI remplaced an ULA 6c001-6 by an ULA 6c001-7 chip on issue 3B board. It is "crucial" to remove R32 and adding the 2x NAND gates ??? or not ? Thanks.
[QUOTE=Winston;197694]Not really, they get used plenty anyway - whenever lower RAM is accessed (so regularly by the ULA)[/QUOTE]
Humm, maybe changing the R32 value to 150 or 220 Ohms ?
(2x NAND gates do an 20-30 ns propagation delay) -
Disable onboard memoryWould this work...? Access to onboard I/O can be disabled by holding IORQGE high. Would it be possible to create a MEMRQGE in a similar way to disa…
The ULA controls the lower RAM (including contention by withdrawing the ... if the CPU goes for lower RAM at the same time as ... the /CAS signal from reaching lower RAM when you want yours paged ... left alone - and that way, lower RAM will continue to get refreshed ... -
Poorly Spectrum + Fault diagnosis help needed!Hi, I've got a Spectrum+. Sometime in the past I broke it and sent it off to be fixed. It came back working good as new, but with an issue 2 board i…
Almost certainly the lower 4116 RAM. The ULA normally gets ... usually does so because the lower RAM went bad.
RAM. Refer to the diagram ... one of the 4116 RAM chips, and check the ... changing out the 4116 RAM. You'll probably find ... -
Poorly Spectrum + Fault diagnosis help needed!Hi, I've got a Spectrum+. Sometime in the past I broke it and sent it off to be fixed. It came back working good as new, but with an issue 2 board i…
... if any of the 4116 RAM is non-intermittently bad (i ... shots, it's been bad lower RAM. (That's not to say ... 't cause that, but 4116 RAM doesn't seem to age ... would suggest swapping the 4116 RAM for known good 4116 first ... -
Poorly Spectrum + Fault diagnosis help needed!Hi, I've got a Spectrum+. Sometime in the past I broke it and sent it off to be fixed. It came back working good as new, but with an issue 2 board i…
... if any of the 4116 RAM is non-intermittently bad (i ... shots, it's been bad lower RAM. (That's not to say ... 't cause that, but 4116 RAM doesn't seem to age ... would suggest swapping the 4116 RAM for known good 4116 first ... -
Poorly Spectrum + Fault diagnosis help needed!Hi, I've got a Spectrum+. Sometime in the past I broke it and sent it off to be fixed. It came back working good as new, but with an issue 2 board i…
... hot. Especially the 4116 RAM chips. Change any 4116 ... 4) Test upper RAM - sometimes, bad upper RAM just stops working so ... t work. Sometimes, bad RAM will stop the machine initialising ... , and fool you into suspecting lower RAM!
Really, you ... -
Spectrum Diagnosis: Purple is not my colour!Hi, I thought the self-fault-finding amongst you might appreciate my learning experience this afternoon in fixing my home-made speccy 48K. Yesterda…
... changed all 8 of the lower ram chips with another kind of ... just black).
The two lower pins of each chip (right ... had already removed all upper ram chips (and installed bases) untill ... -
Poorly Spectrum + Fault diagnosis help needed!Hi, I've got a Spectrum+. Sometime in the past I broke it and sent it off to be fixed. It came back working good as new, but with an issue 2 board i…
Thanks to the kind RAM chip doner, I got the ... at a speccy with dead lower RAM. :???:
I think this ... -
spectrum PSU'sI've read contradictory info on which psu(ie amp rating) is for which spectrum. :confused: The models and amp ratings are 1.2A, 1.4, 1.85 and 48k, …
... and convert it into a lower, extremely stable voltage, at any ... go off to power the lower RAM block etc.
So ... -
Alternative chips for upper RAM blockDoes anybody know of a way to use 4464 chips instead of 4164 for the upper RAM block in a 48K machine? If not 4464 then something a little more avai…
... Eprom 27C128
and uper RAM with 62256 SRAM without any ... ROM socket. I also changed lower RAM with
2 x 4464 ... -
Alternative chips for upper RAM blockDoes anybody know of a way to use 4464 chips instead of 4164 for the upper RAM block in a 48K machine? If not 4464 then something a little more avai…
... Eprom 27C128
and uper RAM with 62256 SRAM without any ... ROM socket. I also changed lower RAM with
2 x 4464 ... -
Alternative chips for upper RAM blockDoes anybody know of a way to use 4464 chips instead of 4164 for the upper RAM block in a 48K machine? If not 4464 then something a little more avai…
... of 4164 for the upper RAM block in a 48K machine ... 4464s for both upper and lower RAM. The 4464 is a 4 ... 15) and have quadruple redundancy RAM...
If replacing a ... -
Speccy just snuffed it while playing 3D Pinball :(I have two speccys but the one I use most has just given up the gost! :-( game froze up and now all I get is flashing patterns and lines:-( Everyt…
... 've got a duff 4116 lower memory chip. If you have ... if it's dead upper RAM the Spectrum will still boot ... power supply can also kill lower RAM, and it's a really ... -
Speccy just snuffed it while playing 3D Pinball :(I have two speccys but the one I use most has just given up the gost! :-( game froze up and now all I get is flashing patterns and lines:-( Everyt…
... power supply can also kill lower RAM, and it's a really ... -
PC power source and Spectrums.I'm planning to use a basic PC ATX power source (300W) for all my sinclair equipment, but I have two questions: - I've read about some nasty things …
... because as you say, a lower RAM chip can go short and ... -
Interface rom - Need help to dump itHi, I have temporarily an interface that is similar to a multiface. It has an NMI button and displays a menu where states can be saved and pokes ent…
... 'll be one or more lower RAM chips, the Z80 could be ... way, I'd be suspecting lower RAM (there are 8 of those ... . Then I'd start testing RAM. -
Interface rom - Need help to dump itHi, I have temporarily an interface that is similar to a multiface. It has an NMI button and displays a menu where states can be saved and pokes ent…
... 'll be one or more lower RAM chips, the Z80 could be ... way, I'd be suspecting lower RAM (there are 8 of those ... . Then I'd start testing RAM.[/QUOTE]
I am ... than you guys.
Lower ram appeared fine with Mr. W ... -
At the Carboot sale today.Today at the carboot sale I picked up An Acorn Electron -I see these all the time, An Official Branded BBC Micro Datacassete Recorder - I'v…
... died shortly after too (bad lower RAM). Before I repaired it, I ... -
At the Carboot sale today.Today at the carboot sale I picked up An Acorn Electron -I see these all the time, An Official Branded BBC Micro Datacassete Recorder - I'v…
... died shortly after too (bad lower RAM). Before I repaired it, I ... -
A question about HTML.Why did the W3C depreciate the align attribute of the <DIV> tag. What replaces it? Is alighnment purely at CSS level now. Scottie_UK.
... CSS to me. But my lower ram is faulty. :D )
