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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…
... self-test, but displaying results on LEDs so that the ULA needn ... clock signal supplied by the ULA, you'll be perfectly in ... for contended memory (since the ULA will stop the CPU clock ... than trying to stop the ULA from accessing the screen memory ... -
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…
... self-test, but displaying results on LEDs so that the ULA needn ... clock signal supplied by the ULA, you'll be perfectly in ... for contended memory (since the ULA will stop the CPU clock ... than trying to stop the ULA from accessing the screen memory ... -
A Spectrum that fixes itselfWell, the modulator on my 128K toastrack machine fixed itself. It used to drift horribly within the first half hour or so of power up, but now it's a…
... nice toasty warmth of the ULA, and regular use (I only ... the first Terminator. You can test if this is true by ... -
+2B ram chips?Hi all, I have got 2 Plus2B`s and 1 Plus2 gray case. Ok the one Plus2B don`t work, so I tried to see if I could pin down the problem. I changed the …
RAM or ULA chip would be my major ... obviously been inside it. The ULA can be done, but as ... the bother of changing it. Test the RAM first, then the ... working +2a yourself, you could test the ram.....
The ... -
ZX81 - Modulator problems...Not a spectrum I know, but does anybody here have an experience of repairing ZX81s? When I dusted mine down recently and plugged it in, the display …
... [/url]
One simple test I do is to use ... distortions, its likely that your ULA is acting up.
ZX Spectrum 128+ problemsHello!I recently purchased and got myself a spectrum 128+ from ebay.The item did not have an original power supply so i got a power supply of 9volts …
... output) or a faulty Ferranti ULA chipset?[/QUOTE]
Could be ... 't have an 128+ to test it)....
On 48K+ machines ... kind of malfunction being present (ULA, modulator).
Also, what i ... not a Spectrum 128+ compatible ULA, this is for Russian spectrum ...ZX Spectrum 128+ problemsHello!I recently purchased and got myself a spectrum 128+ from ebay.The item did not have an original power supply so i got a power supply of 9volts …
... only, possibly far worse - the ULA. It would have cost Sinclair ... is common for people to 'test' the battery by connecting it ... the other. Even this short 'test' could destroy the regulator if ...ZX Spectrum 128+ problemsHello!I recently purchased and got myself a spectrum 128+ from ebay.The item did not have an original power supply so i got a power supply of 9volts …
... nothing can pass to burn ULA or the like?
test.
Thank you for all ...Spectrum ULAHi new to forum ,and have been a speccy owner/fan since the begining{like most 30 somthins on this forum !) Anyway what i want to know is the ULA th…
... to do a PEEK/POKE test on the 16k chips?
ULA as well as i have ...Does anyone have any working Ferranti's?Does anyone know where I might get hold of a Ferranti ULA5C112E-3?? I think this is the problem with one of my rubber key 48K's as it otherwise wor…
... =Msx2;201783]Does anyone have ULA for spectrum 128+ and +2 ... can't be arsed to test them in one of my ...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…
... .
The ULA controls the image and is ...
2) Swop the ULA and see what happens. Not ... because the ULA is always the cause ... br />
3) Test for components that are getting ... .
4) Test upper RAM - sometimes, bad upper ...How about making a diagnostic program for 128k speccys?Hi guys, I was just chatting with DEATH today about a problem i had with my 128 heatsink spectrum and the need for a 128k speccy diagnostic program …
... , it does require a working ULA and working screen memory to ... it's a simple bit test, or whether it does random ... and it'll run the test.Contention and floating bus timingHello, I was recently playing a bit with memory contention and floating bus stuff in ZXDS and there is one thing which puzzles me a bit. It is the d…
... IRQ 3 states later after ULA pulls INTREQ low. I don ... earliest 1 cycle after the ULA pulled it low. But not ... be off, not some (contention test they perhaps used for the ... />
BTW, as a quick test, could you try to run ...Contention and floating bus timingHello, I was recently playing a bit with memory contention and floating bus stuff in ZXDS and there is one thing which puzzles me a bit. It is the d…
... off, not some (contention test they perhaps used for ... Every test program I run says that the ULA is ... QUOTE]BTW, as a quick test, could you try to run ... is clearly impossible. The ULA requires at least 2 T ... if you understand how the test was carried out.
...Contention and floating bus timingHello, I was recently playing a bit with memory contention and floating bus stuff in ZXDS and there is one thing which puzzles me a bit. It is the d…
... people counting it from when ULA pulls INTREQ low, while others ... the other hand, the float48k test, run on the same machine ...Contention and floating bus timingHello, I was recently playing a bit with memory contention and floating bus stuff in ZXDS and there is one thing which puzzles me a bit. It is the d…
... different machines running the same test program?
Because they ... 1T with respect to the ULA [/QUOTE]
Probably. The ...Contention and floating bus timingHello, I was recently playing a bit with memory contention and floating bus stuff in ZXDS and there is one thing which puzzles me a bit. It is the d…
... 1T with respect to the ULA.[/QUOTE]
BTW, it ... of for how long the ULA holds the INTREQ low. On ... off, the result of this test should be off by 1T ... . Which would mean, assuming the ULA holds the line low for ...Contention and floating bus timingHello, I was recently playing a bit with memory contention and floating bus stuff in ZXDS and there is one thing which puzzles me a bit. It is the d…
... last attribute byte fetched by ULA? This is weird, isn ... 't it? How would ULA know it should apply IO ... work like that the ULA always applies memory contention ... paged in? How could ULA know it is not going ... to use slightly different test for memory contention in ...Contention and floating bus timingHello, I was recently playing a bit with memory contention and floating bus stuff in ZXDS and there is one thing which puzzles me a bit. It is the d…
... an explanation why the ULA does not apply contention ... doesn't clash with the ULA in other cases, however ... way of doing the test is to measure the ... ULA 6 cycle contention period is, then you do the same test ... will work as the ULA contention period always occurs ...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…
... . If you have a spare ULA (check the number against the ... some of the boards specify ULA type XXX or later) - so ... . DEATH knows more about the ULA than I do, though.
test. Just check with a multimeter ...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…
... cause when I wanted to test my repaired spectrum+ but was ... anything out, who knows. ULA chips are quite hardy to ... s the first chip to test during a repair, is ... than 3 or 4 duff ULA chips in my time - ... harmless.
If ULA chips were 20 quid each ...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…
... short anything out, who knows. ULA chips are quite hardy to ... 's the first chip to test during a repair, is that ... than 3 or 4 duff ULA chips in my time - compare ... possibly harmless.
If ULA chips were 20 quid each ...Broken SpectrumsChaps ( & Mrs Death ), I was looking at getting some dynamic ram chips for the next phase of the Harlequin stuff, and I started thinking...... I've…
... ve been looking into the ULA in [B]much[/B] ... doing some real spectrum ULA traces so I can ... the ULA RAS/CAS generation and memory access to test my ... to work out about the ULA, along with the speculative ... and oddities in a "Sinclair ULA Internals" paper. I thought ...MULTITECH pictures[url]http://velesoft.speccy.cz/data-gear.htm[/url]
... have +3 to develop and test it...
[quote]I ... natural due to +3's ULA contention. Don't know...
MULTITECH pictures[url]http://velesoft.speccy.cz/data-gear.htm[/url]
... have +3 to develop and test it...
Well, I ... natural due to +3's ULA contention. Don't know...
MULTITECH pictures[url]http://velesoft.speccy.cz/data-gear.htm[/url]
... port #FE work too, but ULA draw border only each 4T ... .....[/QUOTE]
Yet I test scroll text in DMA DEMO ... "1") and scrolling is unstable, ULA is too slow for writing ...MULTITECH pictures[url]http://velesoft.speccy.cz/data-gear.htm[/url]
... ).[/QUOTE]
I can test DMA on +2 or ZX48 ... use wait for CPU and ULA generate stable CLK 3.5xMHz ...MULTITECH pictures[url]http://velesoft.speccy.cz/data-gear.htm[/url]
[QUOTE=velesoft;220034]I can test DMA on +2 or ZX48+ ... use wait for CPU and ULA generate stable CLK 3.5xMHz ...MULTITECH pictures[url]http://velesoft.speccy.cz/data-gear.htm[/url]
... /WAIT issue there, as the ULA doesn't have to access ... haven't had time to test it, but I'm sure ...
