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Hi,


I think my trusty old 6128 has finally given up on me!   :(


It's connected to a CTM644 but when I switch on the 6128 the screen goes grey and lines move vertically up the screen. There is no border, it covers the whole screen. Is this as bad as I think it is?  :o


1. 6128 power light is on
2. There is a faint noise coming from the speaker which changes when the volume is adjusted - but prolonged key presses don't make a beep
3. CTM644 works with an analogue TV tuner (MP-3)
4. 12V and 5V power supplies from the CTM644 are fine
5. There are no physical signs of damage to the board and it worked fine the last time it was used


I looked at the service manual flowchart, it possibly suggests ULA (40010?). Any ideas whether this is likely or whether there are other possible causes? And is ebay the best place for parts?


Thanks for any help,


JT

If you don't have anything on screen and no sound on keypress (DEL/CLR), most likely failing chips are :
- Z80
- 40010
- OS ROM
- CRTC

The Z80 and 40010 are on socket, so you may try re-settling them.
Also none of these chips are not supposed to heat. A finger test may point the culprit.

For a replacement 40010, just check @TotO (http://www.cpcwiki.eu/forum/index.php?action=profile;u=290) if he still have some in stock.

Thanks Gerald!


I will trying removing and re-mounting the Z80 and 40010. Then see what happens!


I did check for heat on the chips but none were hot tbh - maybe need to leave it on for a bit longer!


Thanks again,


JT

This is where I bought my 40100:

Amstrad CPC 464 / 6128 ULA 40010, Mutant Caterpillar Games Ltd Retro Store (http://www.mutant-caterpillar.co.uk/shop/product_info.php?products_id=3767http://)

This is where I bought my CRTC:

ACORN BBC MICRO REPLACEMENT IC - HD6845SP HITACHI VIDEO CRTC CONTROLLER | eBay (http://www.ebay.co.uk/itm/ACORN-BBC-MICRO-REPLACEMENT-IC-HD6845SP-HITACHI-VIDEO-CRTC-CONTROLLER-/252372574231?hash=item3ac293e017:g:9LQAAOSw5ZBWKl8W)

Thanks Higgy :) I've bookmarked them :)

I think I will need some bits! Just not sure which ones yet?

I left it on for a while and the Z80 was warm and the CRTC was too.

Should I start with the Z80 (cos it looks easier   ;D  ) ? and where do i get one?

*writes down shopping list*

Thanks
JT

Those business links are expansive (twice the real price). Just contact me if you prefert to get them cheaper...
I have some GA, CRTC and UK OS ROM chips in stock to repair your CPCs. (I have to check for CPU)  ;)

Hi TotO,

Thanks, I think I was looking at your website earlier. I will try to remove the Z80 and 40010 and try re-mounting them. Need to find an IC puller first. If this doesnt work I will message you to get some bits!  :)

Thanks,

JT

@johnnyt (http://www.cpcwiki.eu/forum/index.php?action=profile;u=1753)
Your reply appeared in a tiny tiny font. I corrected it, that is why you see your message as "edited"  :)

Quote from: johnnyt on 12:22, 11 May 16
Hi TotO,

Thanks, I think I was looking at your website earlier. I will try to remove the Z80 and 40010 and try re-mounting them. Need to find an IC puller first. If this doesnt work I will message you to get some bits!  :)

Thanks,

JT

A flathead screwdriver is all you need to remove the ICs. Just lever them carefully going from one end to the other until they're completely free.

Bryce.

Thanks Bryce - I followed your advice and the chips came off nicely!  :)

Sadly after I remounted them the problem wasn't fixed - but worth a try!

Looks like I need some new bits ;-)

JT

PS thanks to the moderator for making my message readable! :-)

I'd try replacing the Z80 first, however, it might be cheaper in the long run to send it to someone who has spares of all these parts.

Bryce.

Thanks Bryce,

I was going to ask TotO for some prices and see from there.

JT