-
BeginnerIm having a go at fixing a spectrum which has been in the loft for 20 years and would like some advice please.... I have downloaded the 'spectrum se…
... cut the -5v legs of lower ram chips until it's not ... taken away by a faulty RAM chip? What should the resistance ... -
BeginnerIm having a go at fixing a spectrum which has been in the loft for 20 years and would like some advice please.... I have downloaded the 'spectrum se…
... measure resistance seems to be lower than the diode threshold, that ... start thinking about removing all lower RAM (4116) and fitting sockets. Like ... -
BeginnerIm having a go at fixing a spectrum which has been in the loft for 20 years and would like some advice please.... I have downloaded the 'spectrum se…
... variations that occurs when the lower RAM isn't working correctly and ... at least some of the lower RAM is faulty, I also recommend ... . Using this method all the lower RAM ICs can be removed within ... also possible to replace the lower RAM with a fairly simple SRAM ... -
Definitive list of games incompatible with +2A/+3 and of compatible versions (if any)I am trying to compile the definitive list of games which are incompatible with the +2A and the +3 and of their compatible versions, if they are pres…
Definitive list of games incompatible with +2A/+3 and of compatible versions (if any)I am trying to compile the definitive list of games which are incompatible with the +2A and the +3 and of their compatible versions, if they are pres…
... the 48K ROM is at lower ram space. even +2 (grey) and ...Faulty rubber speccy - advice neededHello all speccy hardware gurus :) Recently I moved to a new flat and after a long time have some space (and time) to dig out my old Speccy hardware…
... the Z80, ROM or the lower RAM chips. These are all soldered ... 2 of the IC6 of lower RAM is way higher then on ... may be one of the RAM select logic chips... I guess ...Faulty rubber speccy - advice neededHello all speccy hardware gurus :) Recently I moved to a new flat and after a long time have some space (and time) to dig out my old Speccy hardware…
... that one of the upper RAM ICs wasn't fitted properly ... different values compared to other lower RAM chips, when measuring impedance to ...Repairing another Issue 2 48K Spectrum.I said at the start of the other thread that I've got another one of these and I've started investigating it. The board is more-or-less exactly the …
... a Spectrum with its lower RAM removed and so ... that it would work with RAM installed.
lower RAM socket pins look reasonable ... a problem with the lower RAM, but that something ... stuck. Perhaps an upper RAM problem could cause this ...Repairing another Issue 2 48K Spectrum.I said at the start of the other thread that I've got another one of these and I've started investigating it. The board is more-or-less exactly the …
... have double checked the 4116 RAM in another Spectrum and it ... access to some of the lower RAM or perhaps some bits in ... C54 installed. This led to lower RAM corruption in another Spectrum, but ...what is this crazy modfound a speccy in my loft yesterday,and it seems to have an external heatsink modd i havent the foggiest about speccys heres a few pics [url]http://i…
... on the screen. Im thinking lower ram now, specifically IC9 which is ...Use a +2/+3 case as a replacement keyboard for 48KI was just wondering if a 48K Spectrum motherboard could be housed in a +3 case, and somehow the keyboard be connected so that it could have a proper…
... original 48k rom to the lower ram bank. I seem to remember ...Use a +2/+3 case as a replacement keyboard for 48KI was just wondering if a 48K Spectrum motherboard could be housed in a +3 case, and somehow the keyboard be connected so that it could have a proper…
... original 48k rom to the lower ram bank. I seem to remember ...Would anyone be interested in......Hi, I'm wondering if there would be much interest in an expansion card for the speccy that gives a VGA output with enhanced gfx & sound capabilities…
... another 6K of the contended lower RAM for a choice between 8x1 ... fit two screens in the lower 16K for buffering.
RAM of the [I]Shadow of ...Colour blocks on displayHi all, I have just acquired another Sinclair product, my first one being a C5, it's a 48K ZX Spectrum. It shows colour blocks on the display when p…
The lower 16K of RAM is formed by IC6-IC13 ... power supply connections to the lower RAM that led to the failure ...Colour blocks on displayHi all, I have just acquired another Sinclair product, my first one being a C5, it's a 48K ZX Spectrum. It shows colour blocks on the display when p…
... you can socket z80 and lower RAM and try with new chips ...Colour blocks on displayHi all, I have just acquired another Sinclair product, my first one being a C5, it's a 48K ZX Spectrum. It shows colour blocks on the display when p…
... />
[QUOTE=kamilb1998;601859]
Lower memory bank;
IC6 pin ... ULA is /CAS for the lower RAM and attaching a voltmeter to ... the power supply from the lower RAM, either by cutting the circuit ...Colour blocks on displayHi all, I have just acquired another Sinclair product, my first one being a C5, it's a 48K ZX Spectrum. It shows colour blocks on the display when p…
... a ULA fault, but the lower RAM is far more prone to ... could take out your replacement RAM.Three faulty machines - help!I have three Spectrums and all of them have suddenly collapsed and I can?t figure out what?s wrong. New here.... I own three Speccies but all of a …
... on pins on the lower RAM chips (8x 4116, lower left corner of ... are back in place! These RAM chips are very sensitive to ... not: repeat. If upper 32K RAM is socketed, you can just ...4116 SRAM replacement (and ULA timings).As mentioned in another thread, I have spent quite a lot of time experimenting with different circuits and components for using a static RAM IC to re…
... .php/simm-adapter-for-replacing-lower-memory[/url]
Read ... for CPU access to the lower RAM. In earlier Spectrums this means ... address is presented to the RAM for only about 20ns and ...Three faulty machines - help!I have three Spectrums and all of them have suddenly collapsed and I can?t figure out what?s wrong. New here.... I own three Speccies but all of a …
... on pins on the lower RAM chips (8x 4116, lower left corner of ... are back in place! These RAM chips are very sensitive to ... not: repeat. If upper 32K RAM is socketed, you can just ...Three faulty machines - help!I have three Spectrums and all of them have suddenly collapsed and I can?t figure out what?s wrong. New here.... I own three Speccies but all of a …
... 'd [I]suspect[/I] the lower RAM - can you post a screenshot ... patterns / colors [I]which[/I] RAM chips may have gone dud ...ZX Spectrum not working... issue 4S?Hi, I've bought a "new" broken ZX Spectrum +. The idea was to put an harlequin board inside, but for the moment I'm trying to put it in working order…
... Spectrum in place of the lower RAM. It'll almost certainly work ...Three faulty machines - help!I have three Spectrums and all of them have suddenly collapsed and I can?t figure out what?s wrong. New here.... I own three Speccies but all of a …
... is a fault in the lower RAM. The two where the copyright ... be caused by a partial RAM fault.
I'd ... try installing known good RAM for the lower 16K before investigating further ...ZX Spectrum 48k issue 3b power problem?Hi :) I was lucky enough to find a couple of ZX Spectrums at a car boot sale yesterday. I spent the evening fiddling about with one (issue 2) and t…
... to the right of the lower RAM. Axial caps are harder to ...48k Speccy chucks a wobblerI've got a problem with my rubber keyed 48k speccy. When it is first switched on everything is fine but after a couple of minutes the picture on scr…
Most likely bad memory (usually it's the lower RAM).48k Speccy chucks a wobblerI've got a problem with my rubber keyed 48k speccy. When it is first switched on everything is fine but after a couple of minutes the picture on scr…
... as if the contents of lower memory are becoming corrupted. Once ... /> The problem could be the lower RAM ICs themselves, though usually faults ... switching transistors and consequently the lower RAM too. If this Spectrum still ...Difficult to find upper RAM fault.I've recently repaired an issue 3B 48K Spectrum that had a tricky to diagnose upper RAM fault, so I thought I'd post a report of what I found here. …
... never tries to test upper RAM, so I can boot ... this ROM doesn't use lower memory at all (except ... can boot a Spectrum with lower RAM bad chips. System variables, ... all located into non contended RAM.
Depending ... the damage in low RAM, I can even see ...TR4 is goneMy TR4 transistor is burned. Can I replace this transistor with a TIP31B or C ? My 4116 RAM ic?s are showing +0.05V, +5V and +8.49V... :) My Spectru…
... if the -5v supply to lower ram is missing? :-oTR4 is goneMy TR4 transistor is burned. Can I replace this transistor with a TIP31B or C ? My 4116 RAM ic?s are showing +0.05V, +5V and +8.49V... :) My Spectru…
[QUOTE=guesser;617666]Huh? How is that possible if the -5v supply to lower ram is missing? :-o[/QUOTE]
I don't know. :)
All keys work fine.
But when I hit ENTER, the Speccy resets.Repairing another Issue 2 48K Spectrum.I said at the start of the other thread that I've got another one of these and I've started investigating it. The board is more-or-less exactly the …
... on the first byte of RAM. Usefully, this is the ... step a. I confirmed the lower RAM (IC13) was not at ... suspecting that an upper RAM IC would be the ... and PEEK in upper RAM suggested more than one faulty ... de-soldered all the upper RAM and fitted sockets.
...
