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TV Modulator. Can it be repaired?Is it possible, to repair tha TV modulator (after removing it) if it gives wavy picture? I replaced both transistors (tr1/2) and both electrolytic ca…
Won't initialize above 16K RAM - well, either A15 on the ... the chip select for the upper 32K is fried. It's ... between the lower 32K and upper 32K based on the state ... -
Anybody fancy coding this?blah de blah de blah Please ignore, poting error.
These days, use flash - don't bother with eprom. You can replace the ROM by making an external board that connects to the edge connector, and nails ROMCS high just like ZX Interface 2, so that the on-board ROM never gets selected. Simple decoding logic ... -
Testing RAM Chips After RemovalHi I am going to use Winstons Hot Air Gun method of removing the RAM chips from a 4S circuit board. I wish to check the RAM chips, I have a Logic Pr…
... show up RAM errors in the lower part of the 16K, the ... higher part, the upper 32K and the bank-switched RAM ... press the red button. Bingo RAM and ULA I/O diagnostic ... -
InterfaceHi I'm building a spectrum emulator. I've tried to build it as modular as possible, for example I have a zx class that have input and output devices…
... a Spectrum (both ROM and RAM) has what are known as ... the lower 16K bank or upper 32K bank (the way the RAM gets ... -
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 onboard RAM. (I'm only thinking about the upper 32K which ... be done with the lower 16K, but you'd need to ... -
Question on Z80 R/W cycles.Snipped from the complete spectrum ROM disassembly: [CODE] Now the memory is checked. 11DA RAM-CHECK LD H,D Transfer the value…
... errors, such as a partial failure internally with the row/column ... the school! It was a 16k model, and they had to ... idiot tried a ZX-81 RAM pack on it - after which ... idiot with the ZX-81 RAM pack was me by the ... -
Wtf??I won this NZ auction earlier this week [url]http://www.trademe.co.nz/Browse/Listing.aspx?id=116509561[/url] and have been to collect the hardware th…
... as an EPROM in two 16K sections, because...well, all memory ... ROM on ALIAC2 into 32 16K sections.
Think of ... any 32K chip (static RAM, EPROM, ROM, flash - whatever, it ... high when you want the upper half, A14 low when you ... -
'orange' on a spectrumalways wondered why spectrums could never seem to achieve the colour orange? wasn't one of the default colours, and don't remember seeing anything th…
... for the screen2 in the upper 16K of RAM, so we can access ... ]scrcopy[/b] Copies current screen RAM into second screen (Very slow ... -
Custom SAVE Routine work on emulators?Hi, I'm developing a SAVE routine derived from the one present in ROM 48K, and I'm trying to get it work on several emulators (X128, Spectaculator, …
... the routine in upper memory (8000h+) as the first 16K is contended ... priority on reading the lower RAM over the CPU. -
4116 DRAM for 48KSomeone told me I got faulty RAM in my broken 48K. They should be 150ns, right? What would be a good place to buy them from?
... the same problem (lower 16K memory bad) and tried ... replacing it with a static RAM (32K x 8 bit ... address bus for lower RAM, so I connected an ... / writes to the lower RAM. Snow gone, normal operation ... Next I replaced the upper 32K with another single SRAM ... -
Jetpac questionHi all, I just bought a copy of Jetpac off of Ebay and I'm having problems. To start, I'm trying to play it on an issue 2 Speccy with Interface 1, 2 …
... area in the lower 16K that can't be ... stack in the upper part of RAM. Overwriting that will ... , I found two RAM-testing programs today written ...
is intended for 16K machines, and despite the name ... 16K only I think.
No doubt there are more RAM ... -
Jetpac questionHi all, I just bought a copy of Jetpac off of Ebay and I'm having problems. To start, I'm trying to play it on an issue 2 Speccy with Interface 1, 2 …
... the tape tests the lower 16K of RAM. (Select (S)OAK test ... /> The second program tests the upper 32K (both use a machine ... 16K to 48K system, but should be suitable for testing the RAM ... -
4116 DRAM for 48KSomeone told me I got faulty RAM in my broken 48K. They should be 150ns, right? What would be a good place to buy them from?
The 4116 RAM usually causes it, because it' ... test on startup. If the upper 32K has a fault, sometimes ... , and start up as a 16K Spectrum - but not crash. But ... if the lower 16K is defective, all bets are ... left of the PCB. The upper 32K is in two rows ... -
1K Minigame : 3D RacerLast year I started to code a 3D Racer in 1K. The print of the road was however quite flickery so I put it away to pick it up this week again. I deve…
... ROM perhaps?) so labelling it 16K/48K only might not be ... game is 48K. It uses upper memory for speed.
RAM and alter it on the ... -
issue 6a faultyHi All I got issue 6a pcb from ebay with status faulty pcb had bad voltages when I power up I changed tr4 ztx650 and all voltages got back on ic6 I h…
... from the screen to the upper memory. As the Spectrum ... writes certain values to the upper memory. Because the resistors ... data coming from the lower RAM to the ULA. When ... it starts up like a 16K machine. You'll find ... values back out of the upper memory. But you'll ... -
Spectrum+ - multiple issuesHi all Yesterday I picked up a Spectrum+ (via eBay) to add to my collection. Now, before any of the names I recognise from the last few months of l…
... the keyboard membrane). Your upper 32K of RAM is also almost certainly ... program to test the upper 32K of RAM. You may need to ... are faulty depending on the failure mode. A random fill test ... failed chips easiest. Remember Spectrum RAM is one bit wide, not ... -
Photos of MODIFIED ZX SpectrumsIf you have ZX Spectrum/clone with any modification(s), please release photos: (or send me your photos to --SPECCY(a)SEZNAM.CZ--, I upload all to my …
Lower 16K RAM (the 'video RAM') replaced with a static RAM:
[URL="http ... this machine, I replaced the upper 32K with an SRAM as ... -
Noob to Z80 needing +3 helpI'm quite new to z80 programming, but i'm attempting to write some kind of windowing system that will run alongside BASIC on my +3 with Kempston mous…
... if DOS is active, RAM Page 7 is here instead ... the correct RAM bank to the top 16K when it ... routines from the upper bank (as ram page 7 is ... routine is below the top 16K. You can quite happily ... from anywhere, including the top 16K (any arbitrary bank number), ... -
Two dead SpectrumsHi all, Long time since I posted on here. I'm having a bit of a clear-out, and I've re-discovered two Spectrums I had in the loft : One is an orig…
... almost always means the lower 16K of RAM is dead. 4116 memory ... seems to have quite a high failure ... - this will kill lower RAM too because lower RAM needs -5v supplying ... -
Screen display at resetJust something for curiosity: When the Spectrum is reseted by for example NEW a very typical screen is shortly displayed. [IMG]http://i33.tinypic.c…
... OF RAM is set to the working memorybanks.
So if upper ... memory is missing or malfunctioning (i.e. like in a 16K ... -
Screen display at resetJust something for curiosity: When the Spectrum is reseted by for example NEW a very typical screen is shortly displayed. [IMG]http://i33.tinypic.c…
... OF RAM is set to the working memorybanks.
So if upper ... memory is missing or malfunctioning (i.e. like in a 16K ... .[/QUOTE]
Is the 16k model using exactly the same ... />
That is, does the 16k model know it is a ... -
I bought my first ZX Spectrum 48k, now what ?Hi guys ! I recently go to Brussel in Belgium and found a ZX Spectrum at a "flea market" (sorry, I don't the correct word for that, let's call it a …
... a 16K model, and it was added together with the upper 32K RAM ... -
I bought my first ZX Spectrum 48k, now what ?Hi guys ! I recently go to Brussel in Belgium and found a ZX Spectrum at a "flea market" (sorry, I don't the correct word for that, let's call it a …
... a 16K model, and it was added together with the upper 32K RAM ... -
Test ROM Cartridge For SaleI'm selling another load of gear including a Sinclair Research Test ROM Cartridge. [url]http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=4000772…
... loads a routine into the 16K video RAM that executes a tight ... that the machine has 16K or 48K of RAM, i.e. there ... Test.
Failure here may indicate that the RAM refresh is not ... screen full of text.
Failure will be when the text ... -
Diagnosing Spectrum 48k (faulty RAM chip?)I have a Spectrum 48k (I believe it may be an upgraded 16k model) that doesn't work, and never has ever since the owner gave it to me. When you turn …
... available on all the 4116 RAM chips. If -5v is missing ... (for both lower and upper memory). The lowest 16K (addresses 0x4000 to ... 0x7FFF) are all in the 4116 RAM ... -
Diagnosing Spectrum 48k (faulty RAM chip?)I have a Spectrum 48k (I believe it may be an upgraded 16k model) that doesn't work, and never has ever since the owner gave it to me. When you turn …
... clarity: with the 4116 RAM chips removed you will have ... to socket the low 16k of mem.[/QUOTE]
upper 32K RAM works just fine. There ... chips to control that upper 32K, but they can ... /> As for the lower 16K: you could consider a possible ... -
Announcing: The +2A/+3 FLASH ROM adapter boardAs I've mentioned in a couple of other threads, this project is coming along quite well now, so I thought I'd post some details up here. I've built …
... two banks each contain four 16k rom images (a full +2a ... control the selection of the upper and lower 64k banks of ... connection to the spectrum's ram write line (connected to the ... a flying lead to a ram IC) allowing the FLASH rom ... -
16 K Sinclair Spectrums Still Available?Hi. I wanted to know if the 16 K Sinclair Spectrums are still available to buy. I have looked around on the net without any success. Maybe someone kn…
... ;415148]Only for testing: Which ram must be removed on an ... issue 3b motherboard to have 16K?
Micky[/QUOTE ... 16K. The ones to the right near the beeper are the upper ... -
16 K Sinclair Spectrums Still Available?Hi. I wanted to know if the 16 K Sinclair Spectrums are still available to buy. I have looked around on the net without any success. Maybe someone kn…
the lower ram 16k should not be touched if ... function, you mean remove the upper 32k by the beeper tbh ...
