Re: Random Characters

Hi Ed - Yes, they are all interchangeable with the exception of th later 
cost reduced boards which don't have a stand alone PLA - the majority of 
the logic functions are integrated into a single large MMU. I think the 
906114-02 (as well as -03,-04 & -05) was from one of the P or B series 
machines, so no, it will not be compatible.

Rob

On 29/01/2012 17:48, Ed Johnson wrote:
> It's a  906114-02 is that interchangeable with a 906114-01?
>
>
> Best regards,
> Ed Johnson
> (904) 584-4362 VoIP
> (904) 444-5402 Cell
>
> -----Original Message-----
> From: Rob Clarke [mailto:crock@clarke-family.org.uk]
> Sent: Sunday, January 29, 2012 10:10 AM
> To: cbm-hackers@musoftware.de
> Cc: Ed Johnson
> Subject: Re: Random Characters
>
> Some early boards do not have the commodore part number on the PLA. In this
> particular photo it's below the 6510 (cpu) and to the left of the
> 6581 (SID).
>
> If it is the PLA at fault, you can buy a new one here:
> http://www.arcadecomponents.com/catalog/item/3054735/8335676.htm or buy a
> modern replacement here :
> http://retro-donald.de/sinchai-shop/index.php?main_page=product_info&cPath=3
> &products_id=16
> <http://retro-donald.de/sinchai-shop/index.php?main_page=product_info&cPath=
> 3&products_id=16>
>
> rob
>
> On 29/01/2012 16:01, Ed Johnson wrote:
>> I don't see that chip. Can you identify it in this photo?
>>
>> http://upload.wikimedia.org/wikipedia/commons/8/86/C64motherboard.jpg
>>
>>
>> -----Original Message-----
>> From: owner-cbm-hackers@musoftware.de
>> [mailto:owner-cbm-hackers@musoftware.de] On Behalf Of Gerrit Heitsch
>> Sent: Sunday, January 29, 2012 8:56 AM
>> To: cbm-hackers@musoftware.de
>> Subject: Re: Random Characters
>>
>> On 01/29/2012 02:29 PM, Ed Johnson wrote:
>>> I have a C64 that displays random characters on the screen and locks
>>> up when powered on. Sometimes it powers on correctly but within
>>> seconds displays random characters and locks up. I bought it off eBay
>>> and it worked fine for about a week of heavy use but then this
>>> problem
>> started.
>>
>> The usual suspects in this case are the PLA (906114-01), the 74LS258,
>> the CIA that supplies the 2 extra address bits for the VIC and maybe the
> RAM.
>> Also, if any of the chips I mentioned are in sockets, see if removing
>> them and putting them back in helps.
>>
>>     Gerrit
>>
>>
>>
>>
>>          Message was sent through the cbm-hackers mailing list
>>
>>
>>          Message was sent through the cbm-hackers mailing list
>


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