CPC6128 - blaues anzeige

[radu14m]

Moin,


habe heute eine amstrad cpc6128 bekommt, der aus frankreich gekauft wurde.

Nach einschaltung bekomme ich nur eine blaues anzeige. Habe mehrmals ein und ausgeschaltet - manchmal sind 5-6 gelbe buchstaben zu erkennen , manchmal nur balue anzeige.

Die Teile sind kuhl, mit ausnahme von ein teil der 8252T beschriftet ist. Der wird warm, aber nicht heiss.
Alle speicher bausteine sind kuhl.
Eine z80 hatte ich hier, habe ihn ersetzt aber mit das selbe ergebniss. Mit der andere Z80 hatte ich 2 oder 3 mal eine gelbes "border" fur eine sekunde ...und der war warmer...
Woran kann es liegen ?

Wurde ihn gern wieder lebendig machen

Danke euch .

Radu

[Bryce]

Hi,
     willkommen im Forum. Kannst du vielleicht ein Foto des Bildschirms hochladen? Besonders wenn es gelbe Zeichen zeigt.

Bryce.

[radu14m]

Danke man

hier
http://i49.tinypic.com/14w36eq.jpg

und drin:

http://i45.tinypic.com/4ta78y.jpg

[Bryce]

Ok, es ist ein Version 3 6128 (Cost Down Version). Wenn du den Z80 schon ausgetauscht hast, dann wird das Problem entweder beim ASIC oder beim Arbeitspeicher liegen. Wenn der ASIC kaputt ist, hast du pech, die sind nicht zu bekommen. Die Arbeitspeicher ICs wären einfacher zu tauschen. Wird irgendwas warm bei den? Die sind die zwei reihen von 4164 ICs ganz rechts.

Es kann auch sein, daß dein Netzteil nicht genug Strom liefern kann. Hast du den CPC mit einem anderen Netzteil ausprobiert? Wieviel Amper kann das Netzteil liefern?

Was ist ein 8252T ? Meinst du 8255 ? Sonst ist 8252 das Herstellungsdatum eines ICs.

Bryce.

[MacDeath]

Sorry guys but you re at the english part of the forum...


Wilkomen anyway.

[Bryce]

I know, I'll let Gryzor move it to the German section when he's noticed it.

From now on I'll answer in French

Bryce.

[radu14m]

Sorry that i post in german language
the fact is that i get a cpc6128 ( french version ), a cpc that was sendet to me as functional.
Arriving at home, i did not manage to get the start screen, just a blue screen.
After several switches on/off, sometimes i get also some yellow caracters...
no memory chips are hot. Almost all are cold, with one exception: the big IC, noted UM8272A is getting hot. ( floppy controller i think )
I swaped also the Z80 and changed with antother one, that was checked before. Same issue.
The PSU that i used is a old AT PSU, modified. With the same PSU i start my other schneider cpc, so that the delivered Amps should be fine.
thanks for your time and answers..

[Bryce]

They used a UM8272? Interesting, I didn't know that. I thought all CPCs used a µPD765.
It will probably get warm, but it shouldn't get hot. Maybe it's damaged and pulling the voltage down, but that would probably get the same result every time. Not the varying results you are getting.

I'd recommend you clean the contacts inside the power switch first. It may be full of gunk causing the voltage to be too low.

Maybe it's an easy fix?

Bryce.

[radu14m]

Thanks Bryce !
youre right. The IC is getting warm, not hot.
i clean the power switch too, same result.
Also i short the two pins directly, to start the cpc. Same result.

i also get ( but only once)  a screen with a lot of garbage, caracters and textures... in the screen frame.
most of the time i get some yellow characters that are flickering, or an empty blue screen.
Could it be an memory issue ? if yes, what is the easy way to test each IC ?
i check them again, none is warm...

it boders me, the cpc was functional before shipping....

[Bryce]

It might be a dry joint (Kalte Lötstelle) on one of the bits of the Data or Address Bus. But it could also be a dodgy ROM. It really is hard to say.

Bryce.

[radu14m]

where and how should i start the measurements ?

i tought to use a multimeter, and check the pins status of the ICs...

[Bryce]

Well you can at least check the 5V rail, by measuring the voltage across pins 8 (+) and 16 (-)  of any of the 4164 RAM ICs.

Bryce.

[Gryzor]

So you guys switched to English halfway down the thread? Damn you.

In any case, welcome to the forum mate, not many users from your country, I think!

Also: Welcome to Azerbaijan, Bryce, , hope the president buys you a palace with a revolving, golden statue of you (while most are whithering away).

[Bryce]

Also: Welcome to Azerbaijan, Bryce, , hope the president buys you a palace with a revolving, golden statue of you (while most are whithering away).

That's exactly why I moved, (and because they allegedly had the audacity to hack UN Laptops during a Cyber security congress they hosted )

Bryce.

[Gryzor]

And here I was, thinking you just stayed after Euro(??!wtf?!)vision...

[radu14m]

i check now the voltage

[emuola]

That's exactly why I moved, (and because they allegedly had the audacity to hack UN Laptops during a Cyber security congress they hosted )

Bryce.

I knew it! 

[radu14m]

Thanks for the warm welcome. Yes, we switch to english !
Well, i measure - every memory IC gets 5V ( between pin 8 and 16 ).
What should i check next ?

And thanks guys, i really appreciate every suggestion !

LE. I measure all the IC voltages, and they are all getting the 5 V !

[Bryce]

Hmm, not looking good then, likely that the ASIC is damaged. Difficult to say though without being able to test anything else. I assume you don't have an oscilloscope?

Bryce.

[radu14m]

no, unfortunately no.
i found this here...

CPCWiki forum - Index ... aper-blue/

seems to be the same problem ..blue screen....due to a wrong supply ( 12V instead of 5V )?
Should i check the tranzistors for the begining ?

[Bryce]

Yes, but if the supply had been connected the wrong way, you will have burnt out several ICs and the 5V rail wouldn't be 5V. I doubt your CPC has this problem. Have you taken a look at the electrolytic capacitors? Do they all look healthy? No bulging tops or leakage underneath?

Bryce.

[radu14m]

well, i look and everithing looks fine to me...
some pictures :
http://i45.tinypic.com/qxmp2c.jpg
http://i46.tinypic.com/11r3wvs.jpg
i also switch the cpc  on /off for about 20 times, and also get ome other pictures..
http://i48.tinypic.com/2mpbvqe.jpg
http://i50.tinypic.com/2uprbec.jpg
http://i50.tinypic.com/4v4j1x.jpg
http://i49.tinypic.com/2pplst4.jpg
i let also the cpc for about 30 minute on, all IC's are getting warm, not hot.

[Bryce]

In the second picture (46), the PCB looks to be in really good condition, but then if you look at the tracks under the grey wire below the AMSTRAD text, it looks like the tracks have been worn away by the wire. Maybe this happened during transportation? Take a closer look at the tracks there (and generally) and check that the vibration during the transport didn't break a connection.

Bryce.

[radu14m]

you mean this ?

http://i49.tinypic.com/24cte21.jpg

I read i the other thread that the guy removed the 40015 , without 74ls38 multiplexer , and the 74hc14  IC's.
How its possible to run the cpc without them

[Bryce]

Well the 40015 could be seen in one of the first pictures you posted and it definitely had never been removed. If the 74LS38 and 74HC14 have been removed, then the CPC definitely won't work. Can you show us a picture of where they had been?

Have you a link to the thread where this CPC was discussed?

Bryce.