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Debugging a KIM-1 computer

Dwight Elvey

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All this time, I thought it was your board.
If there are enough people interested, I'd dig up the stuff to make more kits. He'd need two sets of boards for the 6530's with only one debug board.
Dwight
 

Novell2NT

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I was just wondering... Since we know the 6530-003 is also bad. In fact scrambled up pretty good. I was wondering if I could place the bad 6530-002 in it's place, to make it easy to take another look at it.
To verify that my bread board project did show me the correct information? Of course this will be addresses at the same location that the 6530-003 would normally be seen at. I just want to take another look at the ROM
section. Can you think of any reasons that I should not do it this way???

PS. I am not receiving alerts at all to my email. So I have to remember to log in to see any new posts.
 

Novell2NT

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Well, I placed the 6530-002 in the 6530-003 socket, to take a look at the ROM and it looks the same as it did on my bread board project. Good code repeating itself every 8 bytes, and there by replacing the code that should be there.
I was thinking there might have been a wiring problem, with my breadboard that was causing this, but now it has been verified. Both ROMs are DOA !!! :cry:
 

daver2

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>>> PS. I am not receiving alerts at all to my email. So I have to remember to log in to see any new posts.

Have you ticked the boxes in your preference settings for "Content options"? I don't use this option (I check on a regular basis), so it could be faulty of course...

Your machine seems to have had a bad time for some reason. Perhaps been tortured by a previous owner!

I wonder if now is the time for someone to think of a more compact 6530 replacement so it has a similar form-factor to a standard 40 pin IC?

Dave
 

Novell2NT

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>>> PS. I am not receiving alerts at all to my email. So I have to remember to log in to see any new posts.

Have you ticked the boxes in your preference settings for "Content options"? I don't use this option (I check on a regular basis), so it could be faulty of course...

Your machine seems to have had a bad time for some reason. Perhaps been tortured by a previous owner!

I wonder if now is the time for someone to think of a more compact 6530 replacement so it has a similar form-factor to a standard 40 pin IC?

Dave
Everything is ticked under Preferences and under account details email options and I have verified that the correct email address is in place.
 

Novell2NT

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I have just uploaded a new video. Showing the now working KIM-1. I also placed the bad 6530-002 in the 6530-003 socket, so that we could take a look at it.
I have to mention that I would never have been able to get this system to boot up again, without the Corsham RRIOT replacement board.

 

Novell2NT

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There are a number of the people that bought my original kit that after using the test board found no issue with the ROMs. The ROM replacement is made of two small PCBs that fit under the 6532. There are two active parts on it, one being a PAL for address decoding and an EEPROM to hold the ROM image. As shipped the EEROM is blank and one uses the Test board and KIM to program the EEPROM. There are two removable jumpers. One to select -002 or -003 usage for the address decoder in the PAL and one to disconnect the write enable of the EEPROM. One of the two boards deals with the PAL and EEPROM, while the other does the pin translation. It all fits under 6532 but adds about 3/8th of an inch to the height of the 6532. Putting one together can be a challenge of soldering. There area number of small wires that go from board to board and also a number of the device pins do not go from board to board. I can understand why it seems that no one built a board from the kit that didn't need it. I don't know if I have any second rev ( working ) PCBs left for that. I do have some of the EEPROMs but not sure if the PALs I have are blank or have working fuses blown. You'd need the diagnostic board to program the EEPROM or program it before mounting,
The best place to get one of the kits is to ask around for those that didn't build the ROM replacement board. They'd have all the needed parts.
You could always build your own from scratch. I don't think anyone else has made one small enough to fit under the 6532.
I suspect with as much of the board you have, working, that replacing the RAMs will likely get it running.
Of those reporting back what they replaced the most common was one or more of the RAMs. I think one had to replace a buffer chip for the RAM bank and another the address decoder.
Dwight
I would like to git a look at your 6532 replacement board, as I could probably use two of them, if I can make them fit. The Corsham board, is too wide to repace both 6530's.
 

Dwight Elvey

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I don't think you have been reading my post.
Anyway, part of the address decoding is different in the RAM and I/O part of the -002 and the -003. Only the ROM part is socket location decoded. Moving the -002 to the -003 location does not change the chips RAM or I/O location decoding, that is done in the chip.
You can see a picture of the two boards in post:

https://forum.vcfed.org/index.php?threads/debugging-a-kim-1-computer.55589/page-2 #38

They essentially fit under the 6532 chip. It does raise the 6532 by about 3/8th inch or so.
I recommend reading the entire post from end to end.
This arrangement uses an EEPROM to replace the ROM part of the replacement. The address changes for the I/O and the RAM are done with the PAL chip.
The EEPROM is programmed by the debug board. in two steps. The first step is to load the code into the KIM1's RAM of the code that executes the programming. It is run, using the next block of EPROM data to initialize the EEPROM that is under the 6532.
The EEPROM I used was intended to be mounted with the leads of a flat pack. This was too wide so I fold the leads under the chip, like a PLCC. I planerize them and pre-tinned them.
In the kits, I did the step of soldering them to the PCB, as the spacing is quite small. I left the construction of the rest of the circuit to the person that bought the kit.
Like I said, to load the EEPROM, you need the debug board. It can be done with the proper attachment of the flat pack to a regular programmer but I do not use the addresses in typical order as the routing of traces was way too constrained. I don't recall if I swapped data bits either. Remember, it was intended to be programmed in place. With the debug board. I don't know if I still have the PAL code or if any of the PALs I have in my box of parts have the correct code.
I do have several of the prototype under 6532 chip boards that is known to have one of the top, easy to get at traces missing.
As I mentioned before I have several of the prototype debug boards that would need a three pullup resistors added and the edge connector pads scrapped clean for the bottom side. ( both not too hard to deal with). I shipped the kits with an edge connector but I don't have any spares. These are hard to find.
If you are interested, I can send a blank EEPROM, programmed PAL ( believed to be correct ) and the two boards.If you want to do both 6532s you'll need two sets.
I would like to recover some of my cost. I'm not in the business of doing this. I created these kits that I sold at close to my cost for the creation of the kits and did not add extra cost for my prototypes, since I needed to fix my board as well.
You can PM me to determine what you expect of me and my time.
 
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