Posts by jlopez

    Removing them all was a must, certain components can interfere multimeter readings (low impedance resistors, dead capacitors, etc.). And yes, I was going the scanner way (scanners don't have either lightning or perspective problems). You read my mind. :S

    Just for the record, months ago I had the backplane documented, but I don't remember where did I post it... Those documents may belong to this thread now and for this reason I'm uploading them here too.

    Thank you very much,


    You chose a tedious job.

    Fortunately the worst part is nearly finished... albeit the connector will prove to be a nightmare. ;)

    At this point six ICs, two resistors, four resistor arrays, four capacitors, a socket and the connector remain soldered. Three new values have been added to the previous list:

    Silk Screen ReferenceIntegrated Circuit Reference

    I'll continue disassembly tomorrow. With a bit of luck I may be able to leave it flat by then.




    A few days ago I started to desolder the P3's CPU board (CAAA08 - CA1102/8HP00067). The desoldering hand pump broke soon afterwards and this Monday received a replacement (which broke after 1h of use, but that's another story :D). Approximately 2/3 of the board has been exposed and the silk screens containing the components is visible in the unearthened region.

    Both resistors and capacitors use the standard references (Rn, Cn; n being a number).

    Resistor arrays use "N24/x" (x being a number).

    Crystals use "QUn" (n being a number).

    Integrated circuits, on the other hand, have a unique reference consisting of a single number and are also labelled with (what I think it is) their TA's part catalog identifier:

    Silk Screen ReferenceIntegrated Circuit Reference

    EPROMs in this board don't seem to have a catalog reference.

    I hope to be able to complete this list soon, and to start real work with the board - so we can get a proper schematic to repair it and also to identify parts of the bank-switching mechanism.



    BTW: Could you meanwhile verify if the 64 KB mode also works? It seems that the 64 KB RAM card in my P3 is now faulty and it would be interesting to test if the machine runs with the Elephant board. However I also suspect an error in the CPU board, hence potential problems with the Elephant board might not automatically be caused by the board itself.

    I have a newer design that has to surpass the 64KB limit. The problem is that either the original trigger and its interactions with the other boards are still not documented. A few months ago I started to trace the board using continuity tests but it is too complicated to do it in a reasonable amount of time. It is also imprecise as broken traces affect the outcome. Without understanding those, any banking design won't be compatible.

    What I do certainly know is that decode is partial and in case of the P3 with two memory boards configuration the data is outputted to the data bus but it is inputted from slot C. To know more I began to disassembly the P3 CPU board (as I understood you needed more information about it) but the desoldering pump broke at mid-job. Fortunately today I have received the replacement and may continue as soon as possible.

    Yes, the memory boards. Piggybacking may help; doesn't always work but most time is a useful trick to test for defective RAM without desolder.

    Do you know if the memory is directly connected to the data bus or there is something in between? Bad memory could cause a system to fail if parasites are introduced into the data bus, for example. My 3032 had a problem with such parasites. There may be other causes... but without schematics is difficult to search for weak points.



    No apologies, sir. Your considerations were fair. And now is more than plausible. ;)

    Is there any logic on the video card that interacts with the ram board?

    The video boards ist working again with the 5027 (I get a correct display from MOS when I switch on the computer), but only with the 16k board removed.

    Really bad news.;(

    I don't know the KISS enough to know but if it is similar enough to the P2 then it shouldn't. Do you have any other memory board to replace them?

    My piece of advice: next time don't test on the KISS... better use a spare unit as a sandbox.

    Do you know if the SRAM boards work on another system?



    Hello helwie44

    Not sure. The reason I started the thread long ago was to find a better datasheet of this ic, which may be used by many computers of different origin. I found one better (I think it was) at bitsavers.


    jlopez Does that mean the CRT-5027 / 5037 and TMS9927 are identical and interchangeable? At least for use in TA/KISS machines?

    5027 is the Intersil reference, while TMS9927 is its reference given by TI (it was second-sourced).

    The VTAC 5027 does not behave the same way as the 5037 while in interlaced mode, but in non-interlaced mode they should be completely compatible.




    I have a board from the arcade "Speed Up" (checked by its reference), from Spanish manufacturer Gaelco. The board seems to contain the EPROMs with the game and its graphics, as well seven custom ICs and what I think it is a Jamma connector (I am not entirely sure because I am not used to arcade hardware).

    The board was made in 1997 and seems to be in good shape but it is only part of the assembly and therefore the system is incomplete. Other than the cabinet what's missing is the board with the CPU (according to my sources, a 68k). Being that incomplete and missing hardware and experience related to arcades, it is offered as untested.

    The price I'm asking is estimated from the cost of some its components, which uncludes four 96-pin connectors: 35€. As the weight of the packaging is aprox. 558g, transport to any country from the EU would be done by the Spanish mail system Correos (13,20€ ordinary; 17,20€ certified).


    Condition: apparently undamaged, untested

    Price: 35€

    Transport: Correos, 13,20€ (ordinary) / 17,20€ (certified); source (page 5).

    If there is any doubt, don't hesitate to ask.



    Gelegentlich mal zur Kenntnis nehmen, wie die Lage in Italien und Spanien ist, sollte den einen oder anderen wachrütteln.

    Daß die Leichen mit Militärlastern aus der Stadt gebracht werden, weil das sonst nicht zu bewältigen ist, gibt es sonst nur in Kriegsgebieten oder Hollywoodstreifen, die das US-Militär verherrlichen.

    Ob dieser Kelch an uns vorüber geht, ist noch längst nicht raus.

    *** Report from Andorra ***

    Infected: 224

    Healed: 3

    Deceased: 3

    The government is taking measures to protect foreign citizens with seasonal employment.

    *** Report from Spain ***

    Infected: 49844

    Healed: 9357

    Deceased: 4858

    The government has reacted too late, too little. It was not until a week ago that their president decided to create a comittee of scientists to help in the decisions.

    There's not anything related to the IQ of people... there are lots of smart people in Spain. The problem is culturally imposed: if Spain is known for anything is for its picaresque. If something is forbidden, then people will certainly do it; the "idiot" is the one who closelly follows the established conventions and then... the disaster happens. I still remember what happened at Totalán... that was pretty sad.

    Picaresque started to be important in society when the empire started to decline. The large amount of dissent, revolts and civil wars until the last century made it a desirable trait for common people to survive in those hostile environments.

    The following are some cases of the Spanish picaresque during this crisis:…allina-uga-lanzarote.html…saltar-confinamiento.html…bar-murcia-el-palmar.html…tado-de-alarma-salir.html

    People would do anything to get some fresh air. Some even react with violence when found by police or gc. In the (approximately) two weeks we've been enclosed I've seen lots of news like the four posted above.

    To close this post, the Darwin Award of the week... this guy (not Spanish) definitely deserves the award.…llenge-lamer-retrete.html


    jlopez : Here in my region, the youth gathers at the evening at the playgrounds and other places drinking and having fun. For sure, school is closed like all recreation offers. So plenty of free time paired with lacking sense for responsibility. No accusation, 25 years earlier I would most likely have behaved likewise.

    I imagine so. :thumbup:

    But you know... that T-Rex and the dog-dressed-guy hurts the eye.

    Murcianic Park

    Walk time, Bobby!

    I hope if your young people doesn't care about their health, at least they do about their pride. People here in the South have shown no respect for neither of the two.

    Wie ist das in anderen Ländern?

    Both in Andorra and in Spain confinement was implemented last week. There are 50+ positives in my country with no casualties at this moment.

    Spain is, but the opposite. The government is scaling their measures to prevent people cheat the system. There were a few exceptions to the quarantine, one of them is walking the dog (just for hygienic purposes) or to go shopping. During those days I've seen things you wouldn't believe... things like:

    * People walking the dog all day

    * People walking a Guinea Pig

    * People walking a cat

    * People walking a goat

    * People walking a radiator

    * People renting their dogs

    * The skyrocketing number of dog walk services

    * Someone disguised as an inflatable T-Rex (Murcia, Spain)

    * Someone disguised as a dog (Escaldes Engordany, Andorra)

    * Confirmed cases of people who was infected (and knowing it) that travelled, sometimes in buses.

    The government measures came too late and while most people react as expected there are still a high number of people who seems allergic to follow instructions. It seems inevitable that the country will follow the Italian path... They have deployed police, Guardia Civil and also the army.

    I also have a friend in Milan who keeps me informed about how the whole thing is going there. Fortunately he seems to be fine.



    About the infection and mortality rate of Spain... It would be better for you to not extrapolate it with Germany. A lot of people reacted in an irresponsible manner to the warnings given by the local governments. Lots of them (mostly from Madrid) understood the quarantine as Holidays and travelled to coastal towns employing AVE, in effect crossing the country with it. Some of those people were infected. According to Murcia's president beaches and bars were full of Spaniards other than Murcians and decreeted the closure of any cultural site and cancellation of any event in order to discourage intranational tourism while the quarantine is enforced.

    Yesterday my government made two public statements. The first one contained early measures such as cancelling all school trips to outside the country or aadvising not to exit the country. It seems that after that the government met as a crisys cabinet and by evening they stated that a case of a 86-year old woman was confirmed, her daughter is a teacher and also was close to her. As a result schools close from Monday on. Other closures include the ski resorts, without them our economy will suffer greatly. The nearest supermarket is empty and I cannot expect the other ones to be different.

    It's official, that crowned virus has finally arrived at Andorra.

    Char ROM was pulled from an (almost) working 8032 as unfortunately this computer came without its own. The replacement was known to be working. The VRAM was tested on that other board and found to be working too. Just as a curiosity, I recently found that they were made by Tesla, soviet-era Czechoslovak manufacturer; this means that the totality of its RAM ICs were from the Eastern Block.

    Hamsterkauf means "hoarding" or

    "stockpiling". Of course, and that is the joke, it could also mean "buying a hamster" .

    But that is not the real point. Have you ever seen a hamster or a sqirrel collecting comestibles? It has large expandable chops. That is, where the german meaning of Hamsterkauf comes from.


    It seems today I've learnt a little more.

    Thank you, both to you and yalsi

    Having removed both PIAs (they were pulling /IRQ down) and replaced B2 (7425) and H1 (74LS74) I can proudly say that after 40 years the /RAS signal is pulsing again. I have but the side effect that the screen is not erased anymore. The two (and a half) lines are permanently on the screen. Doesn't seem to react on /RESET. Next step, fixing the video circuit maybe?


    Ah, ok. What I don't understand by lecture is translated using automatic translator... apparently Google's AI loves hamsters. :)

    Yes, I imagine that the Spanish level is difficult to beat. A lot of "miraculous" remedies are flooding the social networks.

    WAIT! Do people really think that hamsters will protect them??!!??

    That's just crazy! Completely irrational! In Spain there's dumb people in social networks that say drinking baby pee cures Coronavirus...

    I didn't know that modern medicine has been supplanted by witchcraft-era remedies... A general state of panic is being created and when that hapens, people lose their mind.

    Two days ago the spare parts I couldn't buy at Barcelona arrived. I still have no /RAS and /CAS, but I least I found the cause of the CPU being stopped: /irq is permanently down. Today's first test will consist in testing VIA and PIAs, which are the only components that can cause this signal to go low.

    Yes I know the name was for this reason. But again, the situation was completely different from now. The belligerents had banned any kind of publication about the disease and in that case the ban helped propagating it. It seems that we humans like extreme scenarios: a case of complete lack of information vs infornography. We always fail to adopt a correct attitude agains those problems and it seems we never learn. And that brings the next point...

    No, the world isn't smaller. That's the price we pay for globalization. Events in the other side of the globe can affect us directly. In the past, cost of travelling was high and therefore people didn't used to move from their countries very often. Nowadays, the cost barrier has been smashed and as a result transit among far countries increased dramatically. Transmission of diseases and introduction of invasive species of animals are a couple of side effects we experience.

    calm down please.

    I am absolutely calm ... no prob. I just want to participate in this discussion with you & everyone. Everything's fine ... there are no worries. :)

    Ok. I had a different feeling when I read the first post... anyway, glad to know it. :)

    Medical staff are getting really worried, but because both mass media and politicians are causing unrest. This morning I heard an excerpt (I think it was fromRadio València) where they jokingly said that the only news that the Spanish tv media were broadcasting was from coronavirus and Catalan independentists. And this evening... yes, coronavirus and catalans. At least they aren't monothematic anymore.;)

    Forist, calm down please. Things aren't as dark as they paint it. Everybody seems to be overreacting about this issue. Coronavirus is not new, but an old enemy we know since the sixties. During those 50+ years there have been a few outbreaks but the total deathtoll of all of them is nothing serious compared with a single year's mortality of normal flu. Just as Toshi said, it's just that the flu is so common that nobody cares about it.

    About the Spanish flu, both events aren't comparable in any way. Our sanitation level is high enough to help to avoid infection (althought not 100% guaranteed). Back in the times of the Spanish Flu, Europe was putting end to a 5-year war. Maybe Germany wasn't in ruins but the ever-decreasing rationing was making its population to starve; soldiers on both sides weren't better: they couldn't maintain any kind of hygiene in the trenches. That was the perfect scenario for a pandemic. Fortunately this is not the case today.

    My advice: don't worry, it's not worth it.

    I know it's Friday and already a week has passed since I got in possession of the following, but I'd like to present them to you.

    Do you remember the MSX-BASIC tutorial beta tape I found? Well, I'll be able to watch it.

    Seems to be working as far as I could test it. The mechanism was found pretty clean and did not destroy the tape as old VHS players do sometimes. When I opened it I found the whole assembly to be very well assembled, I smelt quality inside. Sometime in the past I opened 2-3 VHS players either to clean or to scrap them and I can assure that they were built cheaply.

    And, when things couldn 't get better...

    I acquired a Commodore PET-2001-8C. It's not working but seems that the video logic is fine. The cassette won't open but I think where I could find a spare unit. It came with a 16KB (unnoficial?) expansion board so this computer is 24KB + 1KB RAM. It wasn't cheap but in the Spain the CBM-PET line is almost nonexistent so it seemed fair.

    Its previous owner came to my grandmother's house (the nearest place from Barcelona at which we use to go) and delivered it himself. That's not the usual practice. And there was a good reason. He sold it using an app called Wallapop, which is a second-hand market portal. Very useful. But once he posted it, he received not only my request but the ones from other collectors and a flood of requests from speculators. The average price of a PET-CBM in Spain ranges from 800-1200€ and those people saw the advertising and wanted to make easy money with his computer. As he wanted the PET to arrive be at good hands (someone to repair and maintain it) he turned down their requests and started to be harassed by them. They insulted and threatened him in order to force a deal for the computer. In response he changed the status of it as "reserved" and considered retiring it. The only reason I have this nice piece of iron in my hands is that my father asked if it was still available, about one week after the change of status. Negotiations began and nearly a month later, when we went near Barcelona, he delivered it to us. I imagine the reason of bringing it to us instead of asking us to pick it up was to prevent us (or whoever) to know where he lives.

    We all know there is a speculative bubble around old computers, consoles and videogames but I wanted you to know that it doesn't affect all zones/regions in the same manner. South of the Pyreneés things are this bad... not to say about the flea markets. Last time I went to Arbeca they asked me 170€ for a broken breadbin C64. I love to go to flea markets, but after 3h travelling finding this kind of "offers" is infuriating. I'm considering if I'll ever return there.

    My region is :censored:.


    I'm glad that I haven't scrapped the first prototype (the one which couldn't stop playing). I have some prototyping boards, like the one used for the patch.

    After the revision , the components for a single-pit board is of 6 ICs (74 series and PIT). Being an eurocard-sized board i'm sure that once the VCA is tested it would fit without issues.

    Thank you again, for your help and your patience. :)