[Techtoolslist] Data I/O Series 22 problem

[vector]

Thank you John !  I was not aware of tha resource.

I'll check it out.

Thanks,

-- Curt

On 2016-04-30 10:40, John Robertson wrote:
> On 04/30/2016 7:22 AM, vector wrote:
>>
>> Following up on my own post....
>>
>> I'm going to take a logic probe to it to check activity on the 
>> address lines during a chip read.
>>
>> Hopefully looking at the schematics that the 4099 connected to that 
>> socket pin is the culprit.
>>
>> I'm gathering that one bit at a time the address lines are latched, 
>> and then the device would read or program.
>>
>> I just hope it is the 4099 and not one of the 'pin driver' modules.  
>> Doubt those can be found anymore.
>>
>> Ebay seller says this works (it passes self test)... so far is not 
>> willing to work with me on the issue.  His listing does indicate no 
>> refunds, but then why list something as working ?  sigh.... I hope it 
>> is that 4099.
>>
>> -- Curt
>
> Hi Curt,
>
> Can't help you with the Series 22, however are you aware of the large
> Data I/O mail list on Yahoo?
>
> <*> To visit your group on the web, go to:
>     http://groups.yahoo.com/group/Data_IO_EPROM/
>
> The series 22 has been discussed there a number of times over the
> years I have belonged. There are about twenty or so people on the 
> list
> with that device in their collection.
>
> John :-#)#
>>
>> On 2016-04-29 16:39, vector wrote:
>>> I purchased a Series 22.... and now that I've ruined 6 Harris 7641
>>> equivalent PROMs (minimum value about $15)... I've determined what 
>>> the
>>> symptoms are I am seeing.
>>>
>>> This is a 512 byte PROM.
>>>
>>> I'm thinking A6 line to the PROM during read is either high or
>>> floating, as if you break the 512 byte range into 8 blocks of 64 
>>> bytes
>>> you should have
>>>
>>> ABCDEFGH
>>>
>>> When I read a good source rom in, I use edit and compare it against 
>>> a
>>> known good hex dump, and I'm seeing
>>>
>>> BBDDFFHH
>>>
>>> with blocks A, C, E, and G missing.
>>>
>>> This would seem to idnicate that the A6 line is high during read.
>>>
>>> Unfortunately my MOD-EMUP which should handle these PROMs 49 times
>>> out of 50 (or so it seems) will read any 7641 or compatible as all 
>>> FFs
>>> (which it probably ins't reading anything... and the FFs were part 
>>> of
>>> the EMUP's software clear).
>>>
>>> I think I read you can read these as a 2732 and the 512 bytes ends 
>>> up
>>> repeated I think in specific positions in the read.... I have to
>>> google that again to see if during the writes, the A,C,E,and G 
>>> blocks
>>> are all 0 still like on a blank PROM.
>>>
>>> I'm going to strip it down to look at the boards... and check first
>>> at the socket.
>>>
>>> If that line is floating will I get this behavior, or only if it is
>>> driven high ?
>>>
>>> Thanks,
>>>
>>> -- Curt
>>>
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