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JM Precision Reproduced 6502 POD

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Ace` View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ace` Quote  Post ReplyReply Direct Link To This Post Posted: 26 Jun 2020 at 8:51pm
I am pretty sure a cmos 6502 (65C02) cpu like you've installed won't work. It looks weird anyway, possibly fake. Try and track down a standard 6502, or borrow one from a board.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote pikadroo Quote  Post ReplyReply Direct Link To This Post Posted: 26 Jun 2020 at 10:28pm
Originally posted by Lurch666 Lurch666 wrote:

I notice you have 74LS245 instead of 74HC245.
Will have to see if it makes a difference on my Z80 build.


LS is what was indicated in the parts list for the 6502 board. I see the Z80 says HC and I have those for that board.

Drew
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ace` Quote  Post ReplyReply Direct Link To This Post Posted: 26 Jun 2020 at 10:32pm
I found a post on klov that confirms 65c02 don't work. So that could be the only problem.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote pikadroo Quote  Post ReplyReply Direct Link To This Post Posted: 26 Jun 2020 at 10:36pm
Originally posted by Ace` Ace` wrote:

I am pretty sure a cmos 6502 (65C02) cpu like you've installed won't work. It looks weird anyway, possibly fake. Try and track down a standard 6502, or borrow one from a board.


Purchased at Mouser as a fall back to 1 MOS 6502 and 4 SY6502 all tired in this pod but didn't do anything and are known to work. My understanding of this 65c02 is it's the same as those (dunno if that means it's cmos I didn't see that in the datasheet) but it has some extra instructions. I figured if I am messing around I'd rather blow up this chip than one of my vintage collection. Smile

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Post Options Post Options   Thanks (0) Thanks(0)   Quote pikadroo Quote  Post ReplyReply Direct Link To This Post Posted: 26 Jun 2020 at 10:38pm
Originally posted by Ace` Ace` wrote:

I found a post on klov that confirms 65c02 don't work. So that could be the only problem.


That's crazy! I swear one of Jerry's videos has this chip in the pod. LOL

Drew
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Post Options Post Options   Thanks (0) Thanks(0)   Quote pikadroo Quote  Post ReplyReply Direct Link To This Post Posted: 26 Jun 2020 at 11:00pm
I just tried the 65C02 in Millipede. It didn't like it and Millipede behaved like a dead CPU in the game, with the garbage screen. I really would have thought this chip would have worked.I would have bet money on it. Confused

Drew


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Post Options Post Options   Thanks (0) Thanks(0)   Quote Lurch666 Quote  Post ReplyReply Direct Link To This Post Posted: 27 Jun 2020 at 7:54pm
74LS574 not turned up so it's going to be at least Monday before I can test my Z80 pod.

@Drew:
Have you done much troubleshooting of your 6502 pod yet?

Are you interested in trying to get it working together because it would be good practice for me if I have problems with the Z80 pod.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote pikadroo Quote  Post ReplyReply Direct Link To This Post Posted: 28 Jun 2020 at 12:58am
Originally posted by Lurch666 Lurch666 wrote:

74LS574 not turned up so it's going to be at least Monday before I can test my Z80 pod.

@Drew:
Have you done much troubleshooting of your 6502 pod yet?

Are you interested in trying to get it working together because it would be good practice for me if I have problems with the Z80 pod.


The only thing I forgot about is I still have a 6532A on the way from Canada as Lurch666 has suggested maybe that chip will be more effective. That is the only other thing I can think it is and without a schematic I am not even really sure what to look at with this thing.

So, failing that I am also trying to get a hold of a guy named marian on klov and I am having some difficulties with that because I am a new user over there. marian has also made a 6502 pod and there is a lot of information on that unit. If I can get one of those and get it assembled working, then I can circle back around and use that pod to look into what might be wrong with the JM Precision pod. Cool eh? Smile

I also have a Z80 pod I need to build and I think Tuesday or Wednesday I will have time to start building that and then we can see what our combined experience is. At least that way we can both be on the same pod. Might just be a problem with the 6502 pod design and the Z80 one is fine.

Drew
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Lurch666 Quote  Post ReplyReply Direct Link To This Post Posted: 28 Jun 2020 at 5:08am
Do you have the original 6502 fluke pod schematic?


I thought these reproduction pods were mostly the same so this would be a good place to start.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Lurch666 Quote  Post ReplyReply Direct Link To This Post Posted: 30 Jun 2020 at 11:44am
574s turned up at last.

And:


It works.

I still have 74LS245 instead of 74HC245 but the self test come up fine.
EDIT:Talking crap about the 74LS245.Replaced them yesterday with 74HC245 that had turned up then promptly forgot I did it(old age).
Now to have a play.

@pikadroo:Now we at least know the Z80 pod works I was thinking about your 6502 pod.
On the schematics it looks like the data and address lines are connected through resistors on the self test socket.
Can you scope out the data lines during self test and see if you have any activity.



Edited by Lurch666 - 30 Jun 2020 at 4:51pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote pikadroo Quote  Post ReplyReply Direct Link To This Post Posted: 01 Jul 2020 at 2:32am
Originally posted by Lurch666 Lurch666 wrote:

It works.
...
Can you scope out the data lines during self test and see if you have any activity.



LOLAwesome! That has to be a relief after hearing me go on about mine. Glad to hear it works for ya. Yeah, I am struggling to get some work done over here and finished so I can end my month and have a few days to play. I really want to see if I can get the Z80 pod working first and then circle around. I haven't had a chance to look at the book schematics but I did see a picture of a real 6502 pod the other day and noticed it did look very similar. So I will look into it more.

Hey I noticed two things I find interesting on what you did there. You have your pins for the DB25 are on the under side of the board and what looks like just a straight through ribbon cable to just a DB25 patch cable. Is that ribbon cable from the pod to the DB25 just straight thru wiring?

Drew
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Lurch666 Quote  Post ReplyReply Direct Link To This Post Posted: 01 Jul 2020 at 4:32am
Yep I didn't want to have to do 25 connections for the DB25 and another 40 for the UUT socket so I figured if I put the connectors under the PCB and this would let me use an old parallel port connector from a PC for the DB25 since with the connector under the board the pins would be in the correct order.
With the UUT since pin 1 of the POD connector goes to pin 40 of the CPU again putting the connector on the underside means that I could just solder the pins of the connector at the other end straight to the corresponding pins of the CPU plug since the way the connectors work with these ribbon cables pin 1 would now connect to the top right of the plug which is pin 40 of the CPU.

Doing this means you have to use longer pins on the connectors between the two boards of the pod so there's room for the connector going to the fluke.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote pikadroo Quote  Post ReplyReply Direct Link To This Post Posted: 02 Jul 2020 at 11:31pm
I've got a Marian 6502 pod on the way, $300.00 shipped and I mean I have two 9010A. So it's not like a complete waste if I can figure this out and get both working. Z80 pod in the works.Big smile

Drew


Edited by pikadroo - 03 Jul 2020 at 4:05am
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