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General Category => Amstrad CPC hardware => Topic started by: radu14m on 22:04, 12 November 12

Title: CPC6128 - blaues anzeige
Post by: radu14m on 22:04, 12 November 12
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 (http://forum.classic-computing.de/wcf/images/smilies/smile.png)

Danke euch .

Radu
Title: Re: CPC6128 - blaues anzeige
Post by: Bryce on 22:46, 12 November 12
Hi,
     willkommen im Forum. Kannst du vielleicht ein Foto des Bildschirms hochladen? Besonders wenn es gelbe Zeichen zeigt.

Bryce.
Title: Re: CPC6128 - blaues anzeige
Post by: radu14m on 22:53, 12 November 12
Danke man :)

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

und drin:

http://i45.tinypic.com/4ta78y.jpg (http://i45.tinypic.com/4ta78y.jpg)
Title: Re: CPC6128 - blaues anzeige
Post by: Bryce on 10:52, 13 November 12
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.
Title: Re: CPC6128 - blaues anzeige
Post by: MacDeath on 12:06, 13 November 12
Sorry guys but you re at the english part of the forum... :-[


Wilkomen anyway.
Title: Re: CPC6128 - blaues anzeige
Post by: Bryce on 15:07, 13 November 12
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.
Title: Re: CPC6128 - blaues anzeige
Post by: radu14m on 20:19, 13 November 12
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..
Title: Re: CPC6128 - blaues anzeige
Post by: Bryce on 22:19, 13 November 12
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.
Title: Re: CPC6128 - blaues anzeige
Post by: radu14m on 23:10, 13 November 12
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....
Title: Re: CPC6128 - blaues anzeige
Post by: Bryce on 23:13, 13 November 12
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.
Title: Re: CPC6128 - blaues anzeige
Post by: radu14m on 23:16, 13 November 12
where and how should i start the measurements ?

i tought to use a multimeter, and check the pins status of the ICs...
Title: Re: CPC6128 - blaues anzeige
Post by: Bryce on 09:33, 14 November 12
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.
Title: Re: CPC6128 - blaues anzeige
Post by: Gryzor on 15:06, 14 November 12
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).
Title: Re: CPC6128 - blaues anzeige
Post by: Bryce on 16:44, 14 November 12
Quote from: Gryzor on 15:06, 14 November 12
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 :D )

Bryce.
Title: Re: CPC6128 - blaues anzeige
Post by: Gryzor on 17:01, 14 November 12
And here I was, thinking you just stayed after Euro(??!wtf?!)vision...
Title: Re: CPC6128 - blaues anzeige
Post by: radu14m on 19:26, 14 November 12
i check now the voltage
Title: Re: CPC6128 - blaues anzeige
Post by: emuola on 19:33, 14 November 12
Quote from: Bryce on 16:44, 14 November 12
That's exactly why I moved, (and because they allegedly had the audacity to hack UN Laptops during a Cyber security congress they hosted :D )

Bryce.

I knew it!  :D
Title: Re: CPC6128 - blaues anzeige
Post by: radu14m on 19:36, 14 November 12
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 !
Title: Re: CPC6128 - blaues anzeige
Post by: Bryce on 20:57, 14 November 12
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.
Title: Re: CPC6128 - blaues anzeige
Post by: radu14m on 21:27, 14 November 12
no, unfortunately no.
i found this here...

CPCWiki forum - Index (http://www.cpcwiki.eu/forum/amstrad-cpc) ... 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 ?
Title: Re: CPC6128 - blaues anzeige
Post by: Bryce on 21:59, 14 November 12
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.
Title: Re: CPC6128 - blaues anzeige
Post by: radu14m on 22:21, 14 November 12
well, i look and everithing looks fine to me...
some pictures :
http://i45.tinypic.com/qxmp2c.jpg (http://i45.tinypic.com/qxmp2c.jpg)
http://i46.tinypic.com/11r3wvs.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://i48.tinypic.com/2mpbvqe.jpg)
http://i50.tinypic.com/2uprbec.jpg (http://i50.tinypic.com/2uprbec.jpg)
http://i50.tinypic.com/4v4j1x.jpg (http://i50.tinypic.com/4v4j1x.jpg)
http://i49.tinypic.com/2pplst4.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.

Title: Re: CPC6128 - blaues anzeige
Post by: Bryce on 22:43, 14 November 12
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.
Title: Re: CPC6128 - blaues anzeige
Post by: radu14m on 21:44, 15 November 12
you mean this ?

http://i49.tinypic.com/24cte21.jpg (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 ???
Title: Re: CPC6128 - blaues anzeige
Post by: Bryce on 09:25, 16 November 12
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.
Title: Re: CPC6128 - blaues anzeige
Post by: radu14m on 17:43, 16 November 12
 
Look here:

Problem screen border black and paper blue (http://www.cpcwiki.eu/forum/amstrad-cpc-hardware/problem-screen-border-black-and-paper-blue/)
Title: Re: CPC6128 - blaues anzeige
Post by: Bryce on 12:16, 17 November 12
Yes, a similar problem. Did you manage to take fotos of where the missing ICs have been removed?

Bryce.
Title: Re: CPC6128 - blaues anzeige
Post by: radu14m on 13:25, 17 November 12
I did not removed any IC from my cpc.
Just found this post where it's mentioned that the cpc runs without some IC's....just wondered if this is possible...
Of course the falulty looks the same ( blue screen ).
At this point i don't know what can i do to my cpc. I want to repair him.
What can i try ? remove/replace some IC"s ?
Any suggestion wolud be great ! ;) thanks.
Title: Re: CPC6128 - blaues anzeige
Post by: Bryce on 13:43, 17 November 12
Unless you really know what you are doing, you shouldn't start swapping ICs, you will possibly cause more damage. Where are you located? Is there anyone local you can give it to for repair? If not, you could send it (just the PCB) to me.

Bryce.
Title: Re: CPC6128 - blaues anzeige
Post by: Devilmarkus on 14:10, 17 November 12
I'd also guess, that some solder dots are bad.
It's very hard to say something until being able to do more testings.

You first should re-solder (but carefully) all CPU (Z80) dots and also the other ICs, too.

Could you take some more detailled photos of the downside of the PCB?
Best with an angle of ~60° to see the solder points.

Especially the area around the Z80 and ROM/RAM?

You can also add them in your forum reply as attachments, so no need for free image hosters...

Do any solder points have a ring around themselves?
Title: Re: CPC6128 - blaues anzeige
Post by: Devilmarkus on 14:27, 17 November 12
It could also be a damaged ROM... (Malfunctioning)
Title: Re: CPC6128 - blaues anzeige
Post by: radu14m on 21:02, 20 November 12
I tought to solder sockets for the memory.
In this way a faulty IC can be easly discovered.

This is a usual method, i saw also on other retro computers like commodore :)

Do somebody have such an CPC, with socketed IC's?

Btw : sockets are oredered and should arrive this week.
Title: Re: CPC6128 - blaues anzeige
Post by: Bryce on 21:14, 20 November 12
Yes you can do that too, but then you'll need 8 ICs, not just two. I have a CPC with all the RAM in sockets, but that was done because all the RAM ICs really were dead due to a piggy back upgrade that went horribly wrong (The upgrade wasn't done by me!). I also have an 800XL with all sockets (every IC, not just RAM) and a 130XE fully socketed too :)

Bryce.

Edit: The comment regarding 8 ICs instead of two is because I mixed up this thread with the 800XL Broken RAM thread :D
Title: Re: CPC6128 - blaues anzeige
Post by: radu14m on 21:21, 20 November 12
do you have a picture with the socketed CPC ?
Title: Re: CPC6128 - blaues anzeige
Post by: Bryce on 21:26, 20 November 12
No, not at the moment. I know it was a 6128 though, but I have several, I'd have to open them all to check which one. It doesn't look like anything special though, just a standard PCB, but with the RAM in sockets.

Bryce.
Title: Re: CPC6128 - blaues anzeige
Post by: radu14m on 21:33, 20 November 12
thanks, i tought that you have a picture somewhere :)
i wait for the sockets and will solder them.

I'll keep you informed with the progress.
Title: Re: CPC6128 - blaues anzeige
Post by: radu14m on 12:48, 01 December 12
could be the LK104 frecvency switch ?
the cpc is the french version !
Title: Re: CPC6128 - blaues anzeige
Post by: Bryce on 13:06, 01 December 12
No, in either position the CPC would display a picture if it was working.

Bryce.
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