Re: CBM 610 troubleshooting

More good info! Ya, my U20 is soldered in... actually so is the other one at U102. Every other custom chip is in a socket...

Steve



>________________________________
> From: Christian Dirks <Toast_r@IdeaLine.info>
>To: cbm-hackers@musoftware.de 
>Sent: Thursday, January 24, 2013 5:36:16 PM
>Subject: Re: CBM 610 troubleshooting
> 
>
>Steve,
>I did some tests on the P500. Things are different there:
>It will start up with the 6525 at U102 removed. (no keyboard)
>It will start up with the 6526 removed. (no IEEE bus)
>It will start up with the 6551 removed. (no RS-232)
>It will start up with the SID removed. (no sound)
>It will NOT start up with PLA #1 (U78) removed.
>It will NOT start up with PLA #2 (U88) removed.
>It will NOT start up with the VIC removed.
>It will NOT start up with the 6525 at U20 removed.
>It will start to TIM with the Basic ROMs removed.
>
>Christian
>
>Am 24.01.2013 22:48, schrieb Steve Gray:
>
>Christian,
>>
>>
>>That is very handy to know! Thanks! I have a P500 that doesn't start up and the one non-socketed chip is a 6525. I tested the others and they are ok. I kinda suspected it anyway but it's good to see probable confirmation. I guess I'll be de-soldering that chip :-)
>>
>>
>>Steve
>>
>>
>>
>>>________________________________
>>> From: Christian Dirks <Toast_r@IdeaLine.info>
>>>To: cbm-hackers@musoftware.de 
>>>Sent: Thursday, January 24, 2013 4:40:41 PM
>>>Subject: Re: CBM 610 troubleshooting
>>> 
>>>The IEEE bus handshake lines are controlled by the 6525
                at U2,
>>>only the data lines are controlled by the 6526 at U1.
>>>So U2 may be bad.
>>>
>>>I did some tests on a working CBM610:
>>>It will start up with the PLA removed, but it will not
                be useable, since there will be no DRAM accessible.
>>>It will start up with the 6526 removed. (No IEEE bus)
>>>It will start up with the 6551 removed. (No RS-232)
>>>It will start up with the SID removed. (No sound)
>>>It will start up with the 6845 removed. (No video)
>>>It will start up with the char-rom removed. (Video not
                readable)
>>>It will start up to the TIM monitor with the Basic ROMs
                removed.
>>>It will NOT start up with the 6525 at U28 removed.
>>>It SHOULD start up with the 6525 at U2 removed with no
                IEEE bus. Since this one is soldered in, I did not test
                it.
>>>Without the Basic ROMs and PLA, TIM will work fine in
                bank 15. CTRL-G will ring the bell. The IEEE bus will
                work. (.L "$",08)
>>>
>>>Christian
>>>
>>>Am 24.01.2013 19:12, schrieb Michał Pleban:
>>>> Hello!
>>>> 
>>>> Anders Carlsson wrote:
>>>> 
>>>>> Unfortunately, replacing the 6526 with a known
                good chip didn't change
>>>>> anything. Also, I tried the 6509 from the 610
                into the 710, and the
>>>>> latter boots to Basic like it should. This
                suggests that both CIA and
>>>>> CPU are good in the 610, and the problem is to
                be found elsewhere. Too
>>>>> bad the 6525's aren't socketed, as I acquired a
                few from Rob before.
>>>> That's too bad. If you don't have an oscilloscope
                and the CIA chip is
>>>> not broken, I guess there's not much you can do
                except shipping it to me
>>>> (I do have an oscilloscope) :-P
>>>> 
>>>> Regards,
>>>> Michau.
>>>> 
>>>>        Message was sent through the cbm-hackers
                mailing list
>>>
>>>
>>>-- Christian Dirks
>>>Toast_r@Idealine.info
>>>
>>>
>>>
>>>      Message was sent through the cbm-hackers mailing
                list
>>>
>>>
>>>
>
>
>-- 
Christian Dirks Toast_r@Idealine.info
>
>

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