avatar_keropi

Accidentally used a 9v PSU on the 6128 plus, what's the damage?

Started by keropi, 22:39, 16 June 16

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keropi

Hiya...


well... I accidentally powered on my 6128+ with a 9v PSU instead of the 5v one (polarity was correct though)  :doh:
And Now when I power the machine I get this screen:




Any idea/guess of what I killed? I get this screen with the basic cartridge and a black screen with no cartridge in the slot.


TIA for any help/tips. Kinda bummed atm  :(



edit:
found Bryce's over-voltage guide, replace ram and hope for the best?  :-X

||C|-|E||

It has border, so I think that there is a good chance that the RAM is failing  :)

chinnyhill10

Quote from: ||C|-|E|| on 23:14, 16 June 16
It has border, so I think that there is a good chance that the RAM is failing  :)


Yeah, looks like the RAM. I've got a Speccy here that has had its RAM fried by higher than expected voltage.


Can't remember the layout of the Plus machines, but do a quick check to see if any of the RAM chips are getting hot. All the failed chips in the Speccy were red hot after 30 seconds. May save you replacing the lot.
--
ChinnyVision - Reviews Of Classic Games Using Original Hardware
chinnyhill10 - YouTube

keropi

thanks for the replies fellows  8)
I will report back tomorrow morning - I just don't have the heart to try anything today...  gonna take the machine with me and open it up on my workbench at the office. I'll let you know how it goes, I really hope it's the ram... wish me luck!






keropi


Just had a look at the machine, I can feel one of the RAM chips (the outer left) getting really hot and this seems to affect the "Amstrad 40464" and 74LS38 ICs that are next to it. I have tested the 74LS38 and it checks out fine , it survived the ordeal.
I am in the process or removing all 4 ram ICs and putting sockets.
Sadly I have no 41464 ram chips in my stash, is there any other compatible part I could use? Maybe 2x larger ram chips instead of 4?

Bryce

Nope stick with 41464. They are quite easy to find. And pray that the ASIC hasn't been damaged because that's not replaceable. Then stand in a corner and hit yourself with a big stick for doing something so stupid to your plus! :D

Bryce.

Duke

Isn't it possible to use the 41256 (it's lots cheaper overhere atleast <$1 pcs), according to RAM - C64-Wiki :
"If you need one of the 4164 chips, you can also use a 41256 instead. You have to solder a short piece of wire between pins 1 and 16 of that chip ...."
Of course thats for C64, but should be OK for CPC aswell, Bryce? Of course using same amount of chips (and wasting the remaining space of the chips).

I have to do a ram replacement to my 6128 aswell :)

Quote from: Bryce on 08:22, 17 June 16
Nope stick with 41464. They are quite easy to find. And pray that the ASIC hasn't been damaged because that's not replaceable. Then stand in a corner and hit yourself with a big stick for doing something so stupid to your plus! :D

Bryce.

keropi

yeah... keeping same psus with different ratings at the same place is not a clever idea  :picard2:
This is what I fear , some custom Amstrad IC died. I have Z80s, AY and 74xxx here but if that large asic in the middle is fried then this is a lost cause. It doesn't seem to get any warm though, so there is still hope maybe  :-X

Bryce

Yes, that's possible, but having messy jumper wires in the CPC for the sake of saving a few cents? Up to you.

Bryce.

@keropi: I have labels on my PSU cables directly at the computer side plug with Voltage and polarity written on it. Too many similar PSUs that are all lying under the same desk.

The fact that you are getting the screen/border would suggest that at least some parts of the ASIC are still working.

keropi

Yeah well lesson learned. I was too lazy to put a label and thus I used another multi-purpose PSU that looks the same.
Since I don't have suitable ram here I'll just remove the damaged one and power up  to see if anything else gets really hot.

Bryce


keropi

I already found the auction for me, the one you linked Bryce has +12eur shipping cost to Greece...
KM41464AP-12 64Kx4bit MOS DRAM DIP 18 1PC | eBay


I removed all ram, powered on and I don't get any IC with high temps. The only one that gets slightly warm (maybe 18~20 degrees? one just feels a really slight warmth when touching it) is the large asic. The screen I get now is the following with rolling garbage:





I'd love to have some ram atm for testing - even with some patching but unfortunately I can't find any suitable. I am really curious whether the machine survived or not .

Bryce

You'll know soon enough when the RAM arrives.

Bryce.

||C|-|E||

About the RAM, the cheapest chips I found, by far, as these:

5PCS Dynamic RAM IC NEC DIP-18 UPD41464C-10 D41464C-10 UPD41464C D41464C | eBay

5 for 1.96 pounds or 2 something euros including delivery cost. I used 2 of them the upgrade the 464 Plus and work well  :)

Bryce

Quote from: ||C|-|E|| on 10:42, 17 June 16
About the RAM, the cheapest chips I found, by far, as these:

5PCS Dynamic RAM IC NEC DIP-18 UPD41464C-10 D41464C-10 UPD41464C D41464C | eBay

5 for 1.96 pounds or 2 something euros including delivery cost. I used 2 of them the upgrade the 464 Plus and work well  :)

Good price, but with 3 weeks delivery time, it's not for people impatiently waiting to find out whether their 6128+ is dead or not.

Bryce.

dragon

Quoteauthor=Bryce link=topic=12109.msg128710#msg128710 date=1466148127]


Nope stick with 41464. They are quite easy to find. And pray that the ASIC hasn't been damaged because that's not replaceable. Then stand in a corner and hit yourself with a big stick for doing something so stupid to your plus! :D

Bryce.

Well tecnically is replaceable, as is selling in donberg electronics or an alternative is sacrificed a gx4000.

Anyway, i not sure if is necesary a working ram to test some features of  the asic. Or at least with the minimum ram working of video memory page.

The test cartridge maybe not used ram, or at least very little.

keropi

Quote from: Bryce on 11:47, 17 June 16
Good price, but with 3 weeks delivery time, it's not for people impatiently waiting to find out whether their 6128+ is dead or not.

Bryce.


heh true, make that 5 weeks for delivery here - everything from the far East takes at least a month to arrive here  ;D
I am getting some loaner ram , I believe I'll know soon enough if the machine works or not.

||C|-|E||

Quote from: Bryce on 11:47, 17 June 16
Good price, but with 3 weeks delivery time, it's not for people impatiently waiting to find out whether their 6128+ is dead or not.

Bryce.

Certainly true, I waited because I was not in a hurry, hehe  :) Good news is that it took less than three weeks, the modules were here in around 10 days. Still not good in you are in a rush, though...

Bryce

Quote from: dragon on 12:04, 17 June 16
Well tecnically is replaceable, as is selling in donberg electronics or an alternative is sacrificed a gx4000.

Anyway, i not sure if is necesary a working ram to test some features of  the asic. Or at least with the minimum ram working of video memory page.

The test cartridge maybe not used ram, or at least very little.

I've mentioned this here before somewhere: Donberg DOES NOT possess any stock, they are a reseller of stock they believe exists somewhere in the world. They are a one/two person enterprise in a small office. Try buying one from them and see if it ever arrives.

Bryce.

||C|-|E||

A GX4000 would be the way to go, but the process is difficult. I would probably buy a new Plus if the ASIC was fried. Having somebody to remove it from the GX4000 and doing the transplant would be expensive, unless you are doing it yourself  :)

Dr Tiger Ninestein

So it's possible to take an asic from a gx4000 and put it into a plus?


I did wonder if this was possible but always assumed it had to be from another plus.

TFM

TFM of FutureSoft
Also visit the CPC and Plus users favorite OS: FutureOS - The Revolution on CPC6128 and 6128Plus

||C|-|E||

Quote from: Dr Tiger Ninestein on 14:48, 17 June 16
So it's possible to take an asic from a gx4000 and put it into a plus?


I did wonder if this was possible but always assumed it had to be from another plus.

It is possible, but the chip is heat sensitive. The process of desoldering and putting it back would be not trivial, you need to have quite a lot of experience  :)

dragon

Quote from: Bryce on 12:28, 17 June 16
I've mentioned this here before somewhere: Donberg DOES NOT possess any stock, they are a reseller of stock they believe exists somewhere in the world. They are a one/two person enterprise in a small office. Try buying one from them and see if it ever arrives.

Bryce.

Oh i not know that thanks for the info!

Quote from: Dr Tiger Ninestein on 14:48, 17 June 16
So it's possible to take an asic from a gx4000 and put it into a plus?


I did wonder if this was possible but always assumed it had to be from another plus.

Is the same chip. From plus to gx4000 only change how is conected phisically.

And today gx4000 is very easy to find new at least here in spain.



Anyway  respect to the electrocuted plus . You don 't have a  cartridge  with a socket eeprom or something.? I build a test cartridge time ago, only to a precaution if he or  the gx4000 fails.

Until you cannot view, you can deslize in the menus taking as referènce the cartridge in the winape, and try things as the sound or colours in the border.

Bryce

Quote from: TFM on 15:53, 17 June 16

Of course they are from .... Ireland!  :laugh: :laugh: :laugh:

Everybody knows that Bielefeld doesn't exist, but since when has it moved to Ireland???

Bryce.


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