Amstrad CPC 6128 (US version) and Zaxon's 4MB expansion card

[HigashiJun]

Sorry to continue hijacking the topic, but I would like to clarify some points.

- The Solavox/US CPC 6128 is not so rare in Spain. Users in this forum like cngsoft, llopis or myself have one. In the spanish amstrad.es forums there are more owners.

I got mine from a Spanish guy on Ebay. He was selling it as a German CPC...

[norecess464]

- Some (unsold?) units came back to Europe and were marketed in Spain. These units have stickers on some keys to adapt the keyboard to the spanish standard:

LOL really?? please can you confirm that (some) unsold US Amstrad CPCs were actually sold in Spain, with some stickers on the keyboard to "hide" the US layout ?!
As a buyer of a new machine, I would be quite offended to get those ugly stickers on the keyboard.

That's great "Historic" info, thank you for sharing 

[HigashiJun]

Ok, got another US version CPC 6128 on Ebay for really cheap... 

I will be able to check whether the expansion card works on this second machine or not.

[deepfb]

LOL really?? please can you confirm that (some) unsold US Amstrad CPCs were actually sold in Spain, with some stickers on the keyboard to "hide" the US layout ?!
As a buyer of a new machine, I would be quite offended to get those ugly stickers on the keyboard.That's great "Historic" info, thank you for sharing 

I can confirm the CPC 6128 pictured, with stickers on some keys, is mine, and that I know of some spanish owners of these "Solavox" models (you may ask cngsoft or llopis, I believe they also have one).But as this doesn't proof anything, I wrote José Luis Domínguez (remember: he was the founder & owner of Indescomp, then sold the company to Sugar and entered the Amstrad Plc board), and he has just replied this:

Parece como si una remesa hubiera vuelto a Europa, e Indescomp la hubiera vendido aquí, castellanizando el teclado con pegatinas como estas: https://flic.kr/p/8ZsoDT. ¿Te suena algo de eso?


PARA NADA .. ES AMSTRAD ESPAÑA NO HICIMOS ESTA ·GUARRERIA" .. SEARS ESTABA MUY DEPECIONADA PORQUE LOS CLIENTES QUERIAN EL DISKETTE DE 3 1/2 Y CANCELÓ LA VENTA EN TIENDAS POR NO PODER DAR CONTINUIDAD Y GARANTIA A LOS CLIENTES.. ASI QUE SUPONGO QUE SE QUITARIAN DE ENCIMA LOS STOCKS COMO PUDIERON Y ALGUNO LLEGARIA A ESPAÑA ..

Is it possible that Indescomp had marketed in Spain some of the unsold CPC 6128 that were intended to be sold in the USA, with those stickers on the keyboard?

ABSOLUTELY NOT. THAT TRICK IS NOT SOMETHING WE DID AT AMSTRAD ESPAÑA. SEARS WAS DISAPPOINTED SINCE CUSTOMERS WERE ASKING FOR A COMPUTER WITH A 3.5" DISK DRIVE INSTALLED. THEY CANCELLED THE SALE [of the CPC 6128; he writes "THEY CANCELLED THE SALE", not "THE LAUNCH"] BECAUSE THEY COULDN'T EXTEND A GUARANTEE PERIOD [for that part]. I GUESS THEY GOT RID OF THE STOCK OF CPCs, AND SOME OF THEM MAY HAVE ENDED UP IN SPAIN"

He strongly denies they were marketed through Indescomp/Amstrad España -we should look further for the re-seller.

[GUNHED]

Back the days when I lived some years in the good old south I brought my great CPC6128 from Bavaria and bought a CTM644 in the USA. It was the US version because it had some very slight differences, somewhere in this forum I posted pics, but they probably won't exist any longer in here. So in brief the mail difference were the 110 Volts instead of 220 Volts PSU inside.


But back to topic... Hard to imagine a reason for the CPC not to boot up when adding an expansion internally. Somehow I fell it's a very nasty well hidden shortcut, which is hard to trace.


Any news from Zaxon?


What's about our hardware specialists... Nobody here to help?

[VintageAdvantage]

He strongly denies they were marketed through Indescomp/Amstrad España -we should look further for the re-seller.

Interesting! Can you ask him how large the stock was that SEARS had and then got rid of? I guess they were the only original channel for 6128 US CPCs (they also kickstarted the Atari VCS exclusively that way etc). And, how many weeks did they try before they canceled. Maybe he even knows how many 6128 were sold by SEARS. This could give a very coarse upper bound for the number of CPCs ever sold in the US. My estimate is a few hundred / one thousand units.

[VintageAdvantage]

What's about our hardware specialists... Nobody here to help?

With that kind of a problem description... impossible. Put it back in the form where it didn't work and send it to Bryce.

[HigashiJun]

But back to topic... Hard to imagine a reason for the CPC not to boot up when adding an expansion internally. Somehow I fell it's a very nasty well hidden shortcut, which is hard to trace.

Any news from Zaxon?

What's about our hardware specialists... Nobody here to help?

Hmm, I'm very confident in my soldering skills and I always double check before powering-on. The problem is the CPC doesn't boot with with the expansion connected to the expansion port either...

[HigashiJun]

I was just thinking about the PSU I use for my CPC (i.e. 5V / 2A).

Even if there's no any voltage drop, the amperage may not be enough to handle this memory expansion card...

Does someone know how much amperes this card draws (and what is the amperage needed by a CPC 6128) ?

[VintageAdvantage]

Unlikely. But you can try a 2.5 A or 3 A 5V PSU.
If that doesn't do it, and you have checked with a 2nd CPC 6128 to rule out that it is not your 6128 that is bad, then I would send it back to Zaxon and ask for a replacement. Is the behavior the same with all switch settings?

Do you have any other expansions that run successfully on that 6128? 

[HigashiJun]

Zaxon's card has only one switch.

Unfortunately, I have no other expansions so I can't check.

When I turn the CPC on, the Gotek drive powers-on and the CPC "ON" led is also lit, so as you wrote, it's unlikely the PSU...

[pelrun]

In my personal experience there's a significant (>=0.4v from memory) voltage drop in my 6128 regardless of how solid the PSU 5v is. So just increasing the current capacity isn't enough.


I didn't get my M4 or some other peripherals working at all until I boosted my input voltage to 5.1v or more to compensate for the fixed drop.


Actually it's just occurred to me that I've got a few super cheap panel meters so I could add one to the main rail to give me a permanent indication of the internal voltage...

[Bryce]

In my personal experience there's a significant (>=0.4v from memory) voltage drop in my 6128 regardless of how solid the PSU 5v is. So just increasing the current capacity isn't enough.


I didn't get my M4 or some other peripherals working at all until I boosted my input voltage to 5.1v or more to compensate for the fixed drop.


Actually it's just occurred to me that I've got a few super cheap panel meters so I could add one to the main rail to give me a permanent indication of the internal voltage...

That's a considerable voltage drop. Have you tried cleaning the power socket and switch?

Btw: Voltage drop can be the result of a PSU not being able to provide enough amps, so in the case of HigashiJun a more powerful PSU may be the solution.

Bryce.

[HigashiJun]

So it's worth to try a PSU with more amps...

I'll get one next week and check what happens.

Cheers.

[pelrun]

Btw: Voltage drop can be the result of a PSU not being able to provide enough amps, so in the case of HigashiJun a more powerful PSU may be the solution.

Yeah, I know, it's just usually the only thing mentioned and it can be frustrating when it doesn't help. True 4A rated power supplies and a lab PSU were used on mine with no success. Increasing the input voltage by even .1v worked immediately (although obviously there's a risk there if you push it too far.)
Thanks for reminding me about the power switch, as there's not really any other possible culprits after I'd replaced the DC jack with a shiny new one. That said, I have cleaned it, I just don't remember if I'd tried bypassing it. It'd also be trivial to measure the resistance across it.

[GUNHED]

So it's worth to try a PSU with more amps...

I'll get one next week and check what happens.

Cheers.

Be careful, more often 5V - 4A PSUs have the same problems! I got plenty of them and most of them loose Volts down to 4,5 or less.
Bryce suggested a PSU - which I currently investigate - that seems to work great, he knows the link to the other thread, it's somewhere here. It's a 20 Euro PSU, but worth its price.

[HigashiJun]

Be careful, more often 5V - 4A PSUs have the same problems! I got plenty of them and most of them loose Volts down to 4,5 or less.
Bryce suggested a PSU - which I currently investigate - that seems to work great, he knows the link to the other thread, it's somewhere here. It's a 20 Euro PSU, but worth its price.

Yes, but mine is still above 5V, even with the expansion card attached...

So the voltage should be OK but the amperage (2A) might be too low for the 4MB card.

[GUNHED]

If Volts are fine, then with an 2A the Amps should be too. Strange...

[HigashiJun]

Yes, it's quite strange...

One of my questions was: how many amps would need a CPC 6128 with a 4MB card added ?

I don't know if a CPC 6128 really draws 1.7 A, but if it's true, the remaining 0.3 A of my PSU might be insufficient for the 4MB expansion.

[Bryce]

If the computer needs more amps than the PSU can supply, you'll see the voltage dropping. If the voltage is steady then the PSU can supply more than the computer needs.

Bryce.

[Munchausen]

One thought that occurs to me is that if the cable is too long it could be a problem as well. It would be best to try it without a cable first. Did you try it on your second CPC yet, or has that not yet arrived?

[protek]

I had some issues with my CPC6128 booting correctly, when I had my X-mass connected on a specific port of my Mx4. When I changed the port, it boots rock solid. I haven't checked if it might just be a bad solder joint on some pin.


Also, Bryce's advice on cleaning the DC jack contacts helped with my CPC464 boot issues.

[GUNHED]

The cable on the expansion port can be 50 cm in length without any problems. The only exception I know wat the SF2 which has a expansion-port-cable length of 15-20 cm max. to work flawless.

So, if your cable length is lower than 20 cm you should be on the save side. Any comments from @Bryce are appreciated. He can explain that better, I only talked from experience.

[Bryce]

The cable on the expansion port can be 50 cm in length without any problems. The only exception I know wat the SF2 which has a expansion-port-cable length of 15-20 cm max. to work flawless.

So, if your cable length is lower than 20 cm you should be on the save side. Any comments from @Bryce are appreciated. He can explain that better, I only talked from experience.

Pretty much correct, but it's a complicated subject. At 50cm you could experience problems with many devices. It all depends on what's near the cable and what frequency the device runs at. Each wire is acting as an antenna, so a switched mode PSU, monitor or other "transmitting" device might be picked up and have the ability to flip bits or cause errors.

However, if the length of the wire matches the interfering frequency (ie: the wire length is equal to a multiple of the interfering wavelength) then you can have issues at even shorter lengths. This can be confusing, because you can have situations where a 40cm cable causes issues, but a 50cm wire works without issues.


Bryce.

[HigashiJun]

Thank you all for your comments !

Just got another PSU (5V 4A) and still the same problem: my CPC boots normally without interface but doesn't boot with interface connected.

My second CPC was delivered to my parents' and I should receive it soon. I could then test if the same problem occurs.

Concerning the length of the cable, it might be a clue: mine is around 44cm.

I will shorten it as soon as I can (lack of time is terrible  ).

Cheers.