Posts by jlopez

    Amazing story! :D

    I noticed the quotation has a line your post don't show... curious.

    No, I don't have a plan to read the memory. I bought it for static display althought I was fully aware that the content is non-volatile, unless read (this kind of memory has destructive read, right?). So bad I don't even know the word size for it... The matrix is 128-bit but I don't know if it is 16 cells x 8-bit or 8 cells x16-bit.:nixwiss: The required voltages are written on the board, so I imagine I could power it. Sounds funny but I have an overhead of months and will have to wait.


    I got my first rope memory!

    Unfortunately I haven't found any background information about the computer itself other than its name "Wagner WAG.40"...

    I also received another core memory board, which is more compact and with more capacity, but is less interesting to see without some magnifying lens.



    As soon as the board arrives and I have some time, I'll report what I find.

    Two days ago the board arrived as expected and, when I had some time just before lunch I made some tests.

    (Top board, my Italian video system; Bottom board, Shiri 's Spanish video card)

    First I checked (again) if there was no shortcircuit in any of the power supply lines. There was no problem.

    I plugged the board at slor nº4 of the Italian unit and turned the system on, being greeted with the RESET message. So, with the new VTAC the board works, and so does with the second VTAC of the lot he bought. Then I proceeded to test the original 5027 only to find it is not broken. Both facts come as a relief as I was expecting a worst-case scenario. Still, even being great news they are confusing.


    The video card works as expected. No VRAM or EPROM fault.

    The monitor was tested with a game console and found to be working.

    His CPU initialized correctly the VTAC on both cases he tested it, judging by the cursor images he shared. So system ROMs seem to be fine.

    Other than the power supply hack (which may prove to be unstable), could the wiring between computer and monitor be the cause of such distortion? Any other board interfering someway?




    The board is in transit and may arrive as soon as tomorrow. Meanwhile I have checked again the SKS schematics. From the description and pictures, and if there isn't another problem with power supply (such as failing -12V on Shiri 's side or broken zener) I have reduced the options to four possible causes, involving up to eight components:

    A) VRAM failure (D5, D6, E5, E6). If the memory was wrong and somehow it always outputs 80h the result would be a screen as the one shown. Still, I thing such a case is so remote that I'm sarting to rule it out.

    B) 74LS175 failure (B4, B5). If the memories were fine but the EPROM doesn't receive a correct value, culprits would be this pair.

    C) 74LS166 shift register failure (B6). If its output maintains a high or undefined value (not low) next component that feeds its inputs with this signal may pull it up and generate an inverted blank screen.

    D) TMS2716 failure (A6). This is the worst possible case to be expected and also the most probable of all scenarios. Was the EPROM the cause, its data output could go high or undefined, making the shift inputs to pull them high internally and generating the inverted blank screen.

    As soon as the board arrives and I have some time, I'll report what I find.



    Hello helwie44,

    After the replacement, image seems stable, at least from what I've seen. It is a perfect blank, but inverted screen.

    Picture courtesy of Shiri

    The replacement is a legit VTAC, otherwise we wouldn't see the cursor (or anything at all). This seems a fault from the video RAM, latches or maybe some other common component coming before the shift register because (as seen on SKS documents and later with the EPROM backups) MSB is the invert signal. As you said, the TA board is a modified SKS but this remains unchanged.

    Yes, Shiri is a bit far, but even if he was near I couldn't meet him due to restrictions on mobility... Still, he sent me the board through mail. When it arrives, I'll give it priority over the PETs.

    Kind regards,



    It's been some time. Last week the VTACs arrived and the one in the card was replaced by one of the Polish units. The image was stable, cursor moved but there was no character at all! The invert signal was also activated, so the screen was green with the exception of the cursor... This means, that the data path from the DIN to the VRAM and from the VRAM to the shift register should be checked. Being completely blank with the invert I imagine:

    A) some 2114 may be faulty.

    B) some 74 series IC in the bus may be faulty.

    He has no scope to check the signals in the card... so he was stuck with it. For this reason, we agreed I would be in charge of the board for some time as I received one of such instruments not long ago. I don't expect it to be a long repair: as the VTAC retains most responsiblity for the generation of the signals, it shouldn't be as complex as a non-6545 PET.




    I have some new things and others that aren't that fresh but also worthy to report.

    With this I regain the ability to repair hardware!

    I found one of the rare tax-evading Amstrad computer!

    I found many interesting things in dump piles near my home, including this ATMega, four breadboards, and some videoconsole boxes.

    My father brought me some astronaut backpack!

    Last, but not least, Toshi sent me the original monitor for the P2. This way, my Italian unit is complete. He was generous and never asked a price! So thank you very much.




    A few months ago I was delighted when I learned the Deutsch word "Hamsterkauf".:hamster:

    It is my turn to expose a word from the country where I was born: "Estraperlo".


    "Estraperlo" comes from the name of an electrical roulette made by two Dutch men called Strauss and Perlowitz. Albeit gambling was forbidden during the Second Spanish Republic, top public officials gave permission to them to operate. This corruption scandal was soon discovered and as most officials in the government were involved (including prominent members as the PM Lerroux and the mayor of Barcelona) prompted the third and last elections of the period, literally destroying the center-right parties and polarizing the country which went into a crude civil war not long after. When the war was over the word was associated with the black market and, after the postwar famine, with anything related to corruption, illegalities, black markets, etc.:capone:

    You may be asking yourself: "Fine, but why is this guy talking about this in an old computers forums?". Well, to be fair, this is the Amstrad forums, I'm talking about Spain and also about something wrong (maybe even illegal) that shouldn't have ever happened. Knowing those facts, you may be already guessing what's going next.8o

    The responsibles of this lied both to the authorities and to their users because they didn't want to pay some taxes... Spanish picaresque at its finest. It is not clear if it was Amstrad itself who gave the order or was the filial company in Spain who did it. Nevertheless, they never got caught. This is the second model, so "Ñ" key and standard BASIC 1.0 ROM (464)... was the older model it would have British keyboard and BASIC 1.1 (664).

    I imagine that as it can only be found in Spain it may be rare to see this piece of hardware around this forums, so I thought you may be interested in seeing it.;)



    Hello Helmut,

    That's a relief. I told him the failure was most likely caused by the VTAC, but I wasn't completely sure. If that's the cause, the computer may be working very soon.

    I haven't only guided him to find what was preventing the computer to start, but I supplied him my remaining ATX adapter and 48K replacement kits.

    gpospi I was writing this when you replied. Thank you! ;)




    Last Friday another Spanish unit appeared. With both overCLK 's and mine's this is the third known unit to appear. This one is like mine and different from overCLK 's. As both units were found in Catalonia while overCLK 's was found in another autonomous comunity the conclusion is that the units sold in the Catalan market were different from the ones of the rest of Spain (which have that stylish Triumph-Adler badge).

    As seen, the case is the standard one for the P2, but with the distributor badge (Guillamet) under the Alphatronic Sticker. My unit doesn't has the badge, apparently it was lost long ago but the glue is still there as a reminder of what once held.

    On the technical side, the computer is also a little different. Up to that point all known P2 units were 64K units (even mine, which is not a "U" model). This one is the unupgraded 48K unit.

    Now, the tests... the power supply is defective. It was shorting 5v, 12v and ground. All the boards were fine, there was no dead capacitor, even in the 48K DRAM card. With the boards in good shape I considered the computer to be ready for a test so I explained his owner how to wire an ATX into the backplane. After he checked the supply voltages from the backplane we considered it to be secure for the power up so he connected the three boards required for minimal operation: CPU, Keyboard and Video. The system resets correctly when powered on (also beeps as it should) and reacts to commands from keyboard. But the video display seems to be faulty.

    The monitor is known to be working fine, so the fault is up to the video interface. I think his problem is CSync but I would like to know what do you think the problem would be. VTAC? :grübel:

    Note: this unit is not mine and I haven't even seen it other than i pictures and a couple of videos, the images posted here were uploaded with the consent of his owner. I'll try to convince him to come here. When he rescued it he said there was some possibility he had the Spanish manuals but after a search he found none. Still, the simple fact to appear was enough to give me one of the best days of the year.



    Greetings and sorry for the long wait.

    There were incidents at home that left me without the mood to continue in projects. Recently I have made some progress.

    Sometime ago I found some breadboards in a junk pile. They are tattered, two of them a bit melted and one lacks a row of contacts. Still, I found them to be reliable when used, I later saved some money and bought more of them and wires and have started prototyping as I should have from the beginning. It was expensive for my current budget but I was tired of not having a proper tool set. And so, I resumed development.

    My experiments with sound were halted in february and since then I learned much more. Still, I had preference on digital over analog electronics and as a result the first complex circuits I made with my new tools are digital.

    I compared what I had done whith one of the most common systems with sound (NES) and found my developing to be far behind. And so I challenged myself to get the closest I could. I think that, with the exception of the DCPM channel, I got near.

    I first built the noise generator. It consists of a 17-bit LFSR: Noise Test

    Then I made the pulse wave generator with variable duty cycle: Pulse Test (Failure)

    This circuit was inspired by the Hellschreiber as I was wondering how would its characters sound. Then I realized if the character ROM was replaced by another circuit whose function was creating a single character, I could easily implement the variable duty cycle. The character is exactly this one:

    0 0 0 0 0 0 0 0

    0 0 0 0 0 0 0 1

    0 0 0 0 0 0 1 1

    0 0 0 0 0 1 1 1

    0 0 0 0 1 1 1 1

    0 0 0 1 1 1 1 1

    0 0 1 1 1 1 1 1

    0 1 1 1 1 1 1 1

    Then I resorted to video circuits, especially the one found in early PETs and the SKS KISS. The resulting circuit was designed by stripping them down. Still, it was a failure. Somehow it produced an awful noise when it shouldn't. After debugging it was found the only 74LS166 shift register I had was defective by failing to output high but it worked fine when outputing low. I patched the circuit with a 10k resistor from the 5v supply pin to the output and worked. Still, the circuit was so sensible that every time I approached my hand it started to generate noise: Pulse Test (Fixed)

    Finally, the sawtooth/triangle section. It just needed a synchronous counter, an XOR ic and some logic to control the invert operation. This means that with simple logic I could generate three different tones. And three tones is what I got. Unfortunately, I'm unable to discern an inverted sawtooth from a non-inverted one: Sawtooth-Triangle Test

    On the analog side, I found some operational amplifiers in my father's stocks of components and started to test them. I start to realize they aren't as complex as I thought and, whith some time may even domesticate them just a little.




    About two years ago I rescued an old AIM/65 with its original documents and many papers. Recently I took a look at those papers and found some interesting information. Comelta not only imported and distributed the AIM/65 in Spain: over time their "expansions" for it became part of a stand-alone computer mounted in a backplane. Prior to the release of "Drac-1" ("Dragon-1" in Catalan), they called it CR-System and apparently its boards were sold apart. While some of the boards are known, I found more board references which can help in making a more comprehensive list. I also found some prices and a release date for some of the boards. My backplane pinout document is slightly different from the only other source I found (mine has a battery supply line). Additionally it is also headlined with "Development Laboratory".

    Unfortunately, there are no schematics but simple descriptions for many of the boards. I uploaded the scans here.



    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.