Re: PET 2001 fix Part 3 - RAM/ROM board etc.

From: Philip Lord <random6000_at_mac.com>
Date: Sat, 14 May 2011 19:31:57 +0900
Message-id: <066124F4-3019-41E3-B298-2C048BFE6B43@mac.com>
I think I figured it:

-------------------------
	H1  901465-01 
	H2  901465-02 
	H3  901447-24 
	H4  901465-03 
	H5  blank
	H6  blank
	H7  blank

One last question: did my voltages off the CPU look ok?

Phil


On May 14, 2011, at 6:30 PM, Philip Lord wrote:

> Thank again,.
> 
> One quick question before trying what you suggest. How are the BASIC2 901465-1/2/3 and 901447-24 ROM images organized on the 2532 and 2716 EPROMs? 
> Do 1, 2, and 3 go on the 2532's at H1,H2 and H4, and the 901447-24 goes on a 2716 at H3????
> I'll give this a go tonight. Fingers crossed.
> 
> Maybe I'll move this thread over to VCF, I don't want to have my emails clogging up peoples lives. Thanks for all the replies.
> 
> Phil
> 
> 
> On May 14, 2011, at 6:19 PM, MikeS wrote:
> 
>> Too bad H5 is dead; the other four can all be 2716s.
>> 
>> There's no easy way to use 2716s there and you can't easily replace one 2716
>> with a 2532, but you can replace a pair ;-)
>> 
>> If you have three 2532s, program 4K images C000-CFFF, D000-DFFF and
>> F000-FFFF into the 2532s and insert them in H1, 2 and 4 respectively, with a
>> 2716 containing E000-E7FF in H3. Leave H5, 6 and 7 empty.
>> 
>> You could even upgrade to BASIC2 while you're at it with the 901465-1/2/3
>> and 901447-24 ROM images.
>> 
>> If you look at the schematic you'll see that each pair of low and high ROM
>> sockets are wired exactly the same; the low 2316 is selected when pin 18 is
>> low and the high one when it's high, and a 2532 essentially combines them
>> with high and low on pin 18 (A11) selecting the high and low 2K halves.
>> 
>> Maybe the VCF forum might have been a better place for this; don't know if
>> anyone else is interested.
>> 
>> As always, take my advice at your own risk ;-)
>> 
>> Good luck; fingers crossed.
>> 
>> mike
>> 
>> 
>> ----- Original Message ----- From: "Philip Lord" <random6000@mac.com>
>> To: <cbm-hackers@musoftware.de>
>> Sent: Saturday, May 14, 2011 4:12 AM
>> Subject: Re: PET 2001 fix Part 3 - RAM/ROM board etc.
>> 
>> 
>> Me again,
>> I have built the adaptor to read the 2316 H5, H6 and H7 into my burner using
>> the 2K resistor. It seemed to work fine.
>> 
>> Now I have a complete list of which ROMs work and which are dead (compared
>> to the 901447 set from Zimmers):
>> 
>> H1- DEAD (00's)
>> H2- ok
>> H3- DEAD (FF's)
>> H4- ok
>> H5- DEAD (every alternate second back of 128k is 00's, every alternate first
>> bank has code but doesn't match 901447-02 at all)
>> H6- ok
>> H7- ok (unfortunately one of the pins completely broke off due to corrosion
>> and I had  built a make shift fix for it, super ugly but works for testing
>> until I can get the Nicolas's RAM ROM card fixed)
>> 
>> So three dead ROMs and one damaged (that sucks). I can burn 2716's for H1
>> and H3, but I'll probably need to build an adaptor for a 2716 at H5. Do I
>> make the adaptor similar to the programmer adaptor you described, but
>> connect pin 18 to GND instead of VCC?
>> 
>> I also forgot to answer you question about 2532's. I do have some 2532's
>> (and some 2732's I think) and my burner can program them. Why is it possible
>> to use these as H5, H6, and H7 replacements if the code is doubled? Is the
>> 2532 pin 18 active high? Doing a little bit of googling seems to suggest so.
>> I'll do some more research.
>> 
>> Cheers
>> 
>> Phil
>> 
>> 
>> On May 14, 2011, at 4:21 AM, MikeS wrote:
>> 
>>> If you have a spare 24pin IC socket, bend out pin 18 to isolate it and put
>>> it between the 2316 and your programmer socket, and you might be able to
>>> read the H5 - H7 ROMs that way; if not, try connecting that 2K resistor
>>> between the bent-out pin 18 and pin 24.
>>> 
>>> Pleasant dreams ;-)
>>> 
>>> m
>>> 
>>> ----- Original Message ----- From: "MikeS" <dm561@torfree.net>
>>> To: <cbm-hackers@musoftware.de>
>>> Sent: Friday, May 13, 2011 3:06 PM
>>> Subject: Re: PET 2001 fix Part 3 - RAM/ROM board etc.
>>> 
>>> 
>>>> The ROM numbers and locations look good, but I would expect H1 to H4 to
>>>> all
>>>> read OK. Why not try putting your respective 2716 equivalents into H1 and
>>>> H3, leaving the originals in H2, 4, 5, 6 and 7.
>>>> 
>>>> BTW, can you program 2532s and do you have any?
>>>> 
>>>> m
>>>> 
>>>> *******************
>>>> 
>>>> ----- Original Message ----- From: "Philip Lord" <random6000@mac.com>
>>>> To: <cbm-hackers@musoftware.de>
>>>> Sent: Friday, May 13, 2011 2:39 PM
>>>> Subject: Re: PET 2001 fix Part 3 - RAM/ROM board etc.
>>>> 
>>>> 
>>>> Don't worry, I'm not insulted at all.
>>>> 
>>>> I believe I have the following ROM set (I'll double check in the
>>>> morning):
>>>> 
>>>> Location  Part Number
>>>> ------------------------------
>>>> H1  901447-09
>>>> H2  901447-03
>>>> H3  901447-05
>>>> H4  901447-06
>>>> H5  901447-02
>>>> H6  901447-04
>>>> H7  901447-07
>>>> 
>>>> And I have followed the above convention for placement. 09, 03, 05, 06,
>>>> 02,
>>>> 04 and 07 in that order.
>>>> 
>>>> When I read the original ROMs in my burner I got the following:
>>>> 
>>>> H1 - full of 00's
>>>> H2 - good
>>>> H3 - full of FF's
>>>> H4 - good
>>>> H5 - full of FF's
>>>> H6 - full of FF's
>>>> H7 - full of FF's
>>>> 
>>>> so is it possible that H5, H6, ad H7 were not read correctly by my
>>>> programmer. H3 also shows full FF's, but H1 read as full 00's...Could it
>>>> be
>>>> that H1 is the only one that is indeed dead?
>>>> 
>>>> I'll remove the two 6520 PIAs, and I'll take a look on VCF for the
>>>> voltages
>>>> thread.
>>>> 
>>>> Thanks again for your time.
>>>> 
>>>> Phil
>>>> 
>>>> On May 14, 2011, at 3:17 AM, MikeS wrote:
>>>> 
>>>>> Sorry, emails crossed and you answered my question before I asked it ;-)
>>>>> 
>>>>> A crude way would be to measure the voltage on the various 6502 pins,
>>>>> especially the Reset, Sync and Ready pins.
>>>>> 
>>>>> There's a thread on VCF right now that might be relevant.
>>>>> 
>>>>> m
>>>>> 
>>>>> ----- Original Message ----- From: "Philip Lord" <random6000@mac.com>
>>>>> To: <cbm-hackers@musoftware.de>
>>>>> Sent: Friday, May 13, 2011 1:55 PM
>>>>> Subject: Re: PET 2001 fix Part 3 - RAM/ROM board etc.
>>>>> 
>>>>> 
>>>>> Thanks André,
>>>>> I only have limited tools. Logic probe, eprom burner and multimeter.
>>>>> 
>>>>> I'll have to snag the keyboard out of my working pet to try the 'LOAD'
>>>>> test.
>>>>> What other ways can I test if the CPU is working?
>>>>> 
>>>>> Phil
>>>>> 
>>>>> 
>>>>> On May 14, 2011, at 2:39 AM, André Fachat wrote:
>>>>> 
>>>>>> 
>>>>>> 
>>>>>> Looking at the further discussion, you are concentrating on the video
>>>>>> part, but is the CPU actually running ok? I didn't see that, may be I
>>>>>> overlooked it. But you mentioned burning new ROMs as the original ones
>>>>>> were dead.
>>>>>> 
>>>>>> If the cpu is not running ok, this could explain the random characters
>>>>>> on
>>>>>> one side and also the "snow", as some random code would not wait for
>>>>>> the
>>>>>> vertical retrace when writing to the screen memory.
>>>>>> 
>>>>>> Did you try checking for example with a tape and typing LOAD and
>>>>>> pressing
>>>>>> the Play button that the tape starts turning?
>>>>>> 
>>>>>> I'd concentrate finding why the CPU isn't working and looking at the
>>>>>> video later.
>>>>>> 
>>>>>> André
>>>>>> 
>>>>>> 
>>>>>> -------- Original-Nachricht --------
>>>>>>> Datum: Fri, 13 May 2011 19:27:34 +0200
>>>>>>> Von: "André Fachat" <afachat@gmx.de>
>>>>>>> An: cbm-hackers@musoftware.de
>>>>>>> Betreff: Re: PET 2001 fix Part 3 - RAM/ROM board etc.
>>>>>> 
>>>>>>> 
>>>>>>> -------- Original-Nachricht --------
>>>>>>> 
>>>>>>>> So now I have a screen of random and slightly deformed characters
>>>>>>>> (seems
>>>>>>>> like the same or similar character layout on each start up though),
>>>>>>>> with
>>>>>>> a
>>>>>>>> pixel flicker through them. I've put pics and a short video up on the
>>>>>>> same
>>>>>>>> page here:
>>>>>>> 
>>>>>>> Sorry to chime in so late only. The pixel flicker might be from the
>>>>>>> fact
>>>>>>> that the CPU accesses the video RAM. The oldest PETs had video RAM
>>>>>>> with
>>>>>>> max
>>>>>>> 1MHz operation only, so when the CPU accesses the video RAM the video
>>>>>>> display presented "snow". The CPU controlled access to the video RAM
>>>>>>> by
>>>>>>> sampling
>>>>>>> the vertical retrace on a VIA pin (VIA Port B ($e840, 59456), bit 5).
>>>>>>> This
>>>>>>> could relate to the fact that characters seem stable when the machine
>>>>>>> resets (switching off?)
>>>>>>> 
>>>>>>> Maybe the VIA has a problem here?
>>>>>>> 
>>>>>>> On a side note: the fact that switching this vertical retrace off
>>>>>>> resulted
>>>>>>> snow, but also faster screen output - no wait anymore - a certain POKE
>>>>>>> was
>>>>>>> found to make that VIA input pin an output - accidentally destroying
>>>>>>> some
>>>>>>> newer models, the "killer poke".
>>>>>>> 
>>>>>>> André
>>>>>>> 
>>>>>>> -- 
>>>>>>> NEU: FreePhone - kostenlos mobil telefonieren und surfen!
>>>>>>> Jetzt informieren: http://www.gmx.net/de/go/freephone
>>>>>>> 
>>>>>>>   Message was sent through the cbm-hackers mailing list
>>>>>> 
>>>>>> -- 
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>>>>>> 
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>>>>> 
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Received on 2011-05-14 11:00:07

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