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 _______________________________________________ Techtoolslist mailing list Techtoolslist@flippers.com https://pairlist7.pair.net/mailman/listinfo/techtoolslist FTP site is: ftp://ttl.arcadetech.org/TTL/Test_Equipment Archive site: http://seven.pairlist.net/pipermail/techtoolslist/
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 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
_______________________________________________ Techtoolslist mailing list Techtoolslist@flippers.com https://pairlist7.pair.net/mailman/listinfo/techtoolslist FTP site is: ftp://ttl.arcadetech.org/TTL/Test_Equipment Archive site: http://seven.pairlist.net/pipermail/techtoolslist/
_______________________________________________ Techtoolslist mailing list Techtoolslist@flippers.com https://pairlist7.pair.net/mailman/listinfo/techtoolslist FTP site is: ftp://ttl.arcadetech.org/TTL/Test_Equipment Archive site: http://seven.pairlist.net/pipermail/techtoolslist/
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
_______________________________________________ Techtoolslist mailing list Techtoolslist@flippers.com https://pairlist7.pair.net/mailman/listinfo/techtoolslist FTP site is: ftp://ttl.arcadetech.org/TTL/Test_Equipment Archive site: http://seven.pairlist.net/pipermail/techtoolslist/
_______________________________________________ Techtoolslist mailing list Techtoolslist@flippers.com https://pairlist7.pair.net/mailman/listinfo/techtoolslist FTP site is: ftp://ttl.arcadetech.org/TTL/Test_Equipment Archive site: http://seven.pairlist.net/pipermail/techtoolslist/
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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
_______________________________________________ Techtoolslist mailing list Techtoolslist@flippers.com https://pairlist7.pair.net/mailman/listinfo/techtoolslist FTP site is: ftp://ttl.arcadetech.org/TTL/Test_Equipment Archive site: http://seven.pairlist.net/pipermail/techtoolslist/
_______________________________________________ Techtoolslist mailing list Techtoolslist@flippers.com https://pairlist7.pair.net/mailman/listinfo/techtoolslist FTP site is: ftp://ttl.arcadetech.org/TTL/Test_Equipment Archive site: http://seven.pairlist.net/pipermail/techtoolslist/
On Saturday, April 30, 2016 09:22:37 AM vector wrote:
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.
Most eBay sellers have no idea if the device works correctly, or even if it works at all. He's probably telling you the truth, as far as he knows. If the device powers up, and passes whatever it has for self tests, it's "working" to him. Actually using it for its intended purpose isn't something most sellers I've dealt with are able to do, or even interested in doing. With eBay, and ancient electronics, it's definitely a caveat emptor experience. _______________________________________________ Techtoolslist mailing list Techtoolslist@flippers.com https://pairlist7.pair.net/mailman/listinfo/techtoolslist FTP site is: ftp://ttl.arcadetech.org/TTL/Test_Equipment Archive site: http://seven.pairlist.net/pipermail/techtoolslist/
participants (3)
-
David Gersic -
John Robertson -
vector