1088XLD - Custom A8 Computer in 1050 Drive Case

[Simply_Graham]

Here Here for that Dr Venkman

Although a pain, you could also try swapping the XEL TK II into the XLD temporarily as you know this works, beside that maybe a photo of the area around the Pokey's and post just in case we can spot anything to help you with it.

 

Meant to mention I can't help much with the vagaries of the display you are getting with the U1MB menu up, perhaps sorted with a software update, however I've only a 130XE with NTSC and that’s stock at the moment

P.S you could try te U1MB in the XEL, and also update the Bios to XLD and swap back when done.

[+MacRorie]

1 hour ago, Simply_Graham said:

 

P.S you could try te U1MB in the XEL, and also update the Bios to XLD and swap back when done.

The BIOS for the XEL & XLD is the same except for the boot "splash" that says XLD instead of XEL, so if you are trying to test and you have the latest "XEL" firmware, it would be virtually the same and a good test.

[flashjazzcat]

Just now, MacRorie said:

virtually the same

Functionally identical, 100 per cent the same apart from the menu logo as you say.

 

[Simply_Graham]

Hi Guys

Yea, I'm aware the two BIOS are similar with the Splash screen's being diffrent, however I did mention an update, I assuming the U1MB has it's original firmware, as Chevymad hasn't got the SIO working as yet

I think in one of Flasgjazzcat's video's there was mention of some odd artifacts, down the left in one of the machines he'd upgraded.

(But that maybe my poor memory or associated with something else.)

Can you think of any reason's at all as to why he maybe getting this ? I believe the screen is stable once booted, just the Menu, maybe Chevymad can add some more information this evening.

[flashjazzcat]

I remember a few specific ANTIC chips were exhibiting PMG issues... Mytek talked about it (possibly earlier in this thread).

[+mytek]

Be nice to see a picture of what the screen looks like when the problem appears .

 

1 hour ago, flashjazzcat said:

I remember a few specific ANTIC chips were exhibiting PMG issues... Mytek talked about it (possibly earlier in this thread).

Yes I remember something about that, but don't recall the exact details. I'll have to scan through this topic and see if i can find it.

 

[flashjazzcat]

2 minutes ago, mytek said:

I'll have to scan through this topic and see if i can find it.

Here you go:

 

[Simply_Graham]

That's great that you picked that out so it may be a simple Antic swap to fix.

 

Mytek

Quick question, in regard XEL MIDI update added MIDI XEL II  I purchased the boards from OSH park ages ago (8 months plus), and appears no version numbers, mentions on ArariBits a newer version of board to correct left channel output, was this simply a track left off.

to discuss should I PM or post on a new topic ?

[+mytek]

It wasn't Antic after all. Scroll down that page that Jon linked to and you'll see it was the CPU that was the actual issue.

 

After replacing Sally all was well .

 

[chevymad]

Swapped pokeys and reprogrammed all pics. Will have to take apart XEL to do anymore swapping. The blue border on the ultimate screen flashes. The basic screen I typed the alphabet several times. Comes out different every time.

[chevymad]

Went through with a magnifying glass and double checked all the resistors. Didn't find anything else. Reseated IO boards, UAV, and Ultimate. Swapped all the major chips with another set, except pic chips. No difference yet. Next I guess I'll take the pics out of the xel and try them.

 

Since the ultimate doesn't have XEL/XLD firmware yet, what issues will that cause? I can pull that chip and update it if I need to.

Edited April 23, 2020 by chevymad

[+DrVenkman]

6 hours ago, chevymad said:

Went through with a magnifying glass and double checked all the resistors. Didn't find anything else. Reseated IO boards, UAV, and Ultimate. Swapped all the major chips with another set, except pic chips. No difference yet. Next I guess I'll take the pics out of the xel and try them.

 

Since the ultimate doesn't have XEL/XLD firmware yet, what issues will that cause? I can pull that chip and update it if I need to.

Did you actually measure continuity from the I/O board keyboard jack all the way down to the TK-II? There are vias around the board you can use to test each line step by step. 

 

The lack of XLD-specific firmware in the U1MB shouldn’t cause any weird issues like keyboard input changes or color changes in the BIOS menu but that reminds me that the U1MB requires a system with a base 64K RAM - do you have a spare SRAM memory chip in case the first one is faulty?

[+mytek]

3 hours ago, DrVenkman said:

o you have a spare SRAM memory chip in case the first one is faulty?

Good point. I believe they also have a working XEL unless I'm  mistaken, so that could serve as a reservoir of known to be good parts.

 

Has the PS/2 keyboard been verified in some manner? And even though I have yet to come across one that isn't compatible, it might be a good idea to try a different brand keyboard to see if that clears up what you are seeing with the jumbled characters. However that wouldn't  cause the graphics glitching.

 

Still wondering if the graphics and keyboard problems are somehow related. Things to check: U12 = 74F08, CPU swap, carefully check that all sip resistors are properly oriented, carefully inspect ALL the solder joints, not just the ones you've done so far.

 

And although it doesn't  necessarily help you, keep in mind that this board design has been proven to work, and if it doesn't then likely there is an assembly problem, or a bad chip. Also I want verify that you have programmed all your PIC chips from the one zipped collection of firmware on the 1088XLD page, and are using TK-II V2.4. In fact I just thought of an interesting test. Do an ALT+F1 to see if it prints out the correct OS version info on screen (you should do this at the SDX or BASIC screens). Next if that works, try doing an ALT+F2 which should list all of the TK-II configuration settings. If that works properly, then we know that the problem is probably the keyboard, and not TK-II or Pokey related. EDIT: or a bad connection leading up to the keyboard.

 

That last test assumes that the keyboard read is at least good enough for TK-II to acknowledge those key combinations. And if it's just the Atari side of things that's messed up, I would expect those combinations to always invoke a response, but probably result in jumbled characters. Another test would be to press ALT+INSERT several times in a row, and you should see the Scroll Lock LED toggling on and off.

 

[Simply_Graham]

Hi Cheveymad

I like Myteks route of checking the TK II by using it's output to the Left Pokey  however if the Serial part from keyboard is playing up may not 'see the ALT, F!,F2 etrc

Although you may have several faults on the XLD, certainly two maybe three at the moment I think it best to check the chips in the XLD one at a time in the known working XEL as eliminates all the components or dry joints / shorts on the XLD. 

 

Depending on what you may have found already, suggest TK II PIC, then each of the Pokey's checking Keyboard responce as well as SIO.

if both Pokey's (check both in the Left Socket on XEL) work fine and still no SIO on XLD, check the PIA chip from the XLD in the XEL.

Added a capture to help follow the TK II connections (highlighted).

 

P.S

I started this post last night (UK time so Dr Venkmen and Mytek have added posts that will hopefully have helped already, did adjust what I started .

 

 

Edited April 23, 2020 by Simply_Graham
Delete image and update notes

[+DrVenkman]

1 hour ago, Simply_Graham said:

Depending on what you may have found already, suggest TK II PIC, then each of the Pokey's checking Keyboard responce as well as SIO.

FYI, the right POKEY has nothing to do with the keyboard interface or SIO. It's purely audio. 

[Kyle22]

That's why he said this (in the very next sentence) :

4 hours ago, Simply_Graham said:

if both Pokey's (check both in the Left Socket on XEL)

 

 

Edited April 24, 2020 by Kyle22
clarity

[chevymad]

All atari chips have been swapped with known good, exact same behaviour before and after. Swapped the sram chip XEL works fine with the xld chip. Xld works same, except I think this got rid of the U1MB color border. I was checking keyboard response and am not entirely sure when the border problem went away. I actually had accidentally double'd my order of 74f08's so I put the others in. No change. My XEL TKII chip was actually version 2.3. No change swapping this chip. I went ahead and upgraded it to 2.4. Still no change, even tried 2.5. All work in the XEL. Alt+F1 and Alt+F2 print various states of gibberish. Sometimes it's almost correct, others its hardly readable. Same TKII prints info fine on the XEL. Went through the solder joints with a magnifier and touched up anything I thought suspect. Looked at the resistor networks and I think they're all in correctly. Tried to test some in situ, found RN4 doesn't read 3.3k on all pins, but.. probably because it's on the board? 

 

I still need to remove the IO boards and recheck them. Tested about 1/2 the main connector for continuity, so far so good. The standoffs i'm using make it semi difficult to remove the boards, thus why I haven't gone further here yet. 

 

So to sum it up, I still have no SIO, keyboard errors, and a yellow power light. Graphics glitch on U1mb is apparently fixed. 

 

Mytek, I know it's not your board design. I have a mistake somewhere or a bad component. I'll keep plugging away til I find it.

Pictures coming in a second....

 

Edited April 24, 2020 by chevymad

[_The Doctor__]

almost looks like a baud rate miss match... can you take a picture showing the 3 crystal positions even if they are not populated?

 

[Bee]

FWW - In the past, on things like this I took pictures with good focus in blocks, I need them to see well.  The point I'm going for while a component in the wrong place or value is aggravating.  The more elusive for me was a solder bridge I couldn't see otherwise.  The smaller problem was harder to find.

 

Just my 2 cents

 

Thank you 

[Simply_Graham]

Well your reducing what can be wrong so, although a bit of a slog, all the Pokeys & PIC have now been tested and known to work.

the PS/2 lines to the I/O level 1 board must be good, so I think ignore them for now as Alt-F1, Alt-F2, etc. appears to work, only the K & KR lines on the left pokey not reading the TK II Chip correctly, that and the SIO I think maybe a common issue.

You could try checking the lines for the K0-K5 & KR1,KR2 lines they are only connected to the Left Pokey & TK II, but not sure its a worthwhile check now.

I'll check what happens during SIO, and Keyboard read/scan, and edit later on.

Just realised you mentioned RN4 earlier, it is critical this is the correct way round, as pulls high both /IRQ & /NMI among others high.

this WILL affect both SIO & Keyborad Reads among other things.

 

 

 

Edited April 24, 2020 by Simply_Graham

[+DrVenkman]

So there appears to be an awful lot of character display issues. Might it be worth checking the components around ANTIC? Let’s see - PIA is also involved in SIO operation, especially with the S2 module (the /MTR line controls MIDI if I recall correctly - don’t have my schematics handy). Do you have the S2 module installed? Might be worth pulling it out just to eliminate as many variables as possible. 

 

Do you have a cartridge port connected? It might be illustrative to see if the machine will run STAR RAIDERS and if so, what it looks like. 

[+DrVenkman]

7 hours ago, _The Doctor__ said:

almost looks like a baud rate miss match... can you take a picture showing the 3 crystal positions even if they are not populated?

 

I don’t think he’ll get a picture at all if the crystals are messed up - they feed GTIA directly, which then provides ANTIC with a base clock signal, which then gives Phi0 to SALLY which is used to create Phi2 and Phi1. That’s why many vintage Atari machines fail to a red or green screen - the clock is oscillating, and so GTIA is producing a video signal and ANTIC is trying to start, but with no display list data on the bus to process. 

[Simply_Graham]

 

Apparently I took to long editing my previous post ..  Agree, Only one clock in a NTSC computer so should be no issue as seeing a screen, wouldn't if clock incorrect as timing for video would be off. Trying a Cart a good idea !!

Also realised you mentioned RN4 earlier, it is critical this is the correct way round, as pulls high both /IRQ & /NMI among others high.

this WILL affect both SIO & Keyboardd Reads among other things.

I've removed the SRAM from mine and taken a shot of the two Resistor networks, RN4 to the right of the picture, as you can see the information is hidden toward the CPU, I'd guessing that you should have the same.

If you remove a whole bunchof chips You can isolate the RN4 resistor pack.

need to remove  CPU U9, 74F08 U12, ANTIC U7, Left Pokey U18, PIA U14 and finally the U1MB module. Right Pokey eliminated as /IRQ goes via Q5, so no connection.

You should then test from a +5V rail to the CPU sockets pins 40, 39, 2, 4, 6, and on each see 3K3 or 3.3K ohms

Between any two of these CPU pins 6K6 as goes to the 5V rail and back, seeing two of the resistors in series.

Some but not all resistor networks can be checked in a similar way. see what the pins are connected too go through the Circuit diagram linking up all the labels. RN5 for instance requires every chip that uses the Data Lines D0-D7 to be removed to check.

I hope this is of some help, and I'm not teaching you to suck eggs.

As My XLD is only dropped into the case bottom, happy to supply photo's of each Resistor Network if it will help you, depends on the supplier as to how they are printed up.

[+mytek]

Somethings amiss with TK-II's reads of the Pokey K0-K5 counter outputs. Basically this is resulting in the out of sync issues between what TK-II sends to the KR1 and KR2 inputs on Pokey, and how Pokey interprets that data. Since it's  erratic, this suggests that one of the counter connections is flakey. Could be a physical problem (bad connection) or a flakey I/O line on the PIC (internal problem). Has a replacement PIC chip been tried?

 

And it could also be a flakey problem with the KR inputs (Pokey) or outputs (PIC).

 

[Simply_Graham]

Hi Michael

I think both the Pokey's and the PIC have been swapped (and reprogrammed) and tested in an XEL and all proved fine. I dont think its the lines between as they are unlikely to be intermittant so I'm thinking there is a problem more with the Control lines of the Pokey something like the /IRQ line not being as it should. or maybe the address lines flacky going to the Left Pokey and reading the wrong registers when interupted to read the keyboard values. This would also cause issues with SIO, although PIA has control lines for SIO, that wouldn't cause the issue with keyboard read unless two faults.