-
48k not startingHi team, I have 2 48k's, one works (Issue 4s), one doesn't (Issue 4a). The non-working one appears to start, but not finish the RAM test. The pape…
... /> [*]Hard way #2 - remove one lower (4116) DRAM chip at a ... with good ones, or a lower RAM module.
[*]Less hard way ... -
48k not startingHi team, I have 2 48k's, one works (Issue 4s), one doesn't (Issue 4a). The non-working one appears to start, but not finish the RAM test. The pape…
... /> [*]Hard way #2 - remove one lower (4116) DRAM chip at a ... with good ones, or a lower RAM module.
[*]Less hard way ... -
Spectrum CapacitorsLooking for some opinions here, if I may? In the 80's and 90's I used to repair Spectrums and other machines for a living so I'm reasonably famili…
... and often lead to the lower RAM being damaged. Those in the ... and that can damage the lower RAM too. -
Spectrum CapacitorsLooking for some opinions here, if I may? In the 80's and 90's I used to repair Spectrums and other machines for a living so I'm reasonably famili…
... and will do to your lower RAM IC's, I'd happily ... -
64k speccydoes anyone have instructions on how to use the extra 16k found in some spectrums?
... asked, the 48k byte RAM machines use either eight 32k ... provision to use any more RAM in the "upper" memory ... comes from 16k bytes "lower" RAM plus two banks of 32k ... DRAM chips) of "upper" RAM. If the board does ... you try searching for 80k RAM.
[b][ ... -
Spectrum +3 blinking yellow/blueI received a +3, which only gives a yellow/blue blinking border during initialization. Pressing BREAK when powering on does not work, neither does a …
... bits 0-3 of contended RAM, i.e. IC3.
Lower RAM or page 5 is all ... . Once the firmware has some RAM to work with in this ... .
Details in the "Lower RAM Testing" section [url="https://github ... -
Spectrom interface ?Hi all, I got 2 of this devices ... :) [img]http://forest.no-ip.org/wos/spectrom/20151006_151428.jpg[/img] [img]http://forest.no-ip.org/wos/sp…
... bank will be copied to lower RAM.
Then it watches ... of the MM content to RAM from ROM. When the second ... -
Issue 1 schematics?I'm fault-finding an issue 1 board. So far I've found a hot memory chip and snipped it's supply legs, then swapped the burnt-out 7805 for a switched…
... important tip is that the lower RAM IC's are in a ... -
Faulty Issue 1Hi all, thought I'd document my efforts in getting another speccy working. I've never done this before so please bear with me... I recently took a p…
... need to put some good lower RAM in? If so, I ... devices) use a ROM based RAM tester (yes, I know the ... board has no RAM), the objective is to see ... has run, remove the 16k RAM chips by cutting all the ... sockets. Then try new 4116 RAM chips, or try Zorn's ... -
Wanted 6C001E-7 ULALooking to replace mine from a issue 4B, anyone got a working one spare in a bag of bits or know where I can get one?
... 4S board. It has a lower ram fault, and 2 caps have ... -
Faulty 48+ Help NeededHi, This is what I get when I plug in the spectrum, this is tuned in. Vid shows a reset. Any ideas, or pointers on the first thing to check. Keyboa…
... that it has a rom/ram check feature, so time to ... /> TR4 and TR5 replaced.
Lower ram replaced
Z80 replaced
Faulty 48+ Help NeededHi, This is what I get when I plug in the spectrum, this is tuned in. Vid shows a reset. Any ideas, or pointers on the first thing to check. Keyboa…
... suspect I have a dodgy lower ram module, or there's something ...Faulty Issue 1Hi all, thought I'd document my efforts in getting another speccy working. I've never done this before so please bear with me... I recently took a p…
... where if I ordered a lower RAM module he'd send me ... some info on how his lower RAM performed.
A few ... in.
Zorn's Ram module plugged straight in and ... 16K speccy? (8K ROM, 8K RAM?) The manual didn't bother ...Issue 3B woesHello there, I currently have a Issue 3B for repairs around, it used to have broken upper and lower RAM, which I replaced with 41256-120 DRAMs (hac…
Oh ... and if I'm quick I can verify that the ZX sees both the upper and lower RAM banks (print peek 23732/23733).
I've also tried to isolate the issue by removing the upper RAM & ICs 23-26. Problem persists.Faulty Issue 1Hi all, thought I'd document my efforts in getting another speccy working. I've never done this before so please bear with me... I recently took a p…
... a report of problems with lower RAM before and as the ULA ... a SRAM to replace the lower RAM.
[b][i]Mark ...Faulty Issue 1Hi all, thought I'd document my efforts in getting another speccy working. I've never done this before so please bear with me... I recently took a p…
... certain that, with the lower RAM module installed, the computer ... corruption; CPU use of the lower RAM is not affected.
... addressing one; sometimes the lower RAM module latches an incorrect address ... have this problem when the lower RAM module is used. I ...Issue 3B woesHello there, I currently have a Issue 3B for repairs around, it used to have broken upper and lower RAM, which I replaced with 41256-120 DRAMs (hac…
... the "isolation" resistors between the lower RAM and the rest of the ... of chips used for the lower DRAM like you have done ... SRAM is being used as lower RAM (a LRR module) and they ...No colors on screen, issue 2.I have a 48k issue 2 with composite mod. When i first pluged it in after i bought it, the screen went yellow and after restart there were no colors a…
Check your power supply voltages on IC13, pin1 = -5v. pin 8 = 12v. A missing 12v rail would cause a B/W display, as well as being none too healthy for your lower RAM.
BNTSC Compatibility?Correct me if I'm wrong, but wasn't the Timex 2068 the only NTSC clone built of the ZX Spectrum? And I use clone lightly... From what I underst…
... the data bus for [the lower RAM and ULA] and the CPU ... is reading data from the lower RAM, a I/O read by ... to be reading from the lower memory for use in displaying ...NTSC Compatibility?Correct me if I'm wrong, but wasn't the Timex 2068 the only NTSC clone built of the ZX Spectrum? And I use clone lightly... From what I underst…
... only reads data from the RAM when it needs said data ... read any data from the RAM.
The ULA only stops ... when the CPU addresses the lower RAM, or certain I/O ports ...NTSC Compatibility?Correct me if I'm wrong, but wasn't the Timex 2068 the only NTSC clone built of the ZX Spectrum? And I use clone lightly... From what I underst…
... when the CPU addresses the lower RAM, or certain I/O ports ... contend just 7K of graphics RAM. It has to contend at ... any memory in the 16K lower RAM), then the ULA doesn't ...Sudden death of ZX Spectrum 48KHello A friend gave me a 48K rubber keyed Spectrum. I brought it home, hooked it up to my little TV and powered it up. I was very happy to see t…
The problem might be the lower RAM or ULA judging by the ...Sudden death of ZX Spectrum 48KHello A friend gave me a 48K rubber keyed Spectrum. I brought it home, hooked it up to my little TV and powered it up. I was very happy to see t…
... . It's to allow OKI RAM to be used as upper ... RAM rather than the Texas Instruments ... for TI or OKI upper RAM.
Check for a ... one or more of the lower RAM ICs. It's a very ...Sudden death of ZX Spectrum 48KHello A friend gave me a 48K rubber keyed Spectrum. I brought it home, hooked it up to my little TV and powered it up. I was very happy to see t…
... make me suspect a faulty lower RAM IC or possibly a faulty ...Sudden death of ZX Spectrum 48KHello A friend gave me a 48K rubber keyed Spectrum. I brought it home, hooked it up to my little TV and powered it up. I was very happy to see t…
... fault is indicative of faulty lower RAM. To be honest, it could ... pointed out that the upper RAM and that several of the ... /> As Zorn has said, test lower RAM, it's all you can ...Sudden death of ZX Spectrum 48KHello A friend gave me a 48K rubber keyed Spectrum. I brought it home, hooked it up to my little TV and powered it up. I was very happy to see t…
... /> As Zorn has said, test lower RAM, it's all you can ... of more of the 4116 "lower" DRAM chips has gone faulty ... ROM/EPROM, a ROM based RAM test program should confirm this ... firmware? Also, I have a RAM turbo interface which takes ROM ...
