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1088XEL Atari ITX Motherboard DIY Builders Thread

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22 hours ago, _The Doctor__ said:

check for backwards components/bad capacitors if a diode or cap is backwards or bad, you may be letting something by you don't want.

nothing backwards ,all joints now checked, values of all transistors checked. orientation etc..   at least 5 x now.. looked under all sockets that I could see for anything jammed.

 

I did have issues with the U1MB - but nothing from that could have effect on the video circuit right?  Otherwise seems to be fine.. computer has run for hours.. with crap video but otherwise fine.

 

LSI chips swapped for 800xl - Chips from 1088 work in 800xl and produce fantastic video via UAV in that machine. Ran Ms.Pacman cart (good colour changes and missile/pl gr) 24h plus all is good.

 

it has been suggested I sub out the UAV.. put the one from the 1088xel in a known good (800xl) machine.. just hate desoldering.. but if thats the next step.. then so be it.   Suggestions?

 

James

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50 minutes ago, Bikerbob said:

it has been suggested I sub out the UAV.. put the one from the 1088xel in a known good (800xl) machine.. just hate desoldering.. but if thats the next step.. then so be it.   Suggestions?

 

What exactly are you desoldering? The 4050 in the 800XL? 

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4 hours ago, DrVenkman said:

What exactly are you desoldering? The 4050 in the 800XL? 

lol.. no funny how no one gets that.. the header that connects the line of the UAV to the board.. in any other machine I have to use wires.. and the header would touch components on the board.. so I have to remove the 5pin header.. put the wire bus in .. or solder direct or some kind of jumper.. then if I am putting it back.. solder that header back in.   I just tend to find my de-solder skill is ok to salvage a component.. but not if I want to reuse pads again and again....

 

James

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25 minutes ago, Bikerbob said:

lol.. no funny how no one gets that.. the header that connects the line of the UAV to the board.. in any other machine I have to use wires.. and the header would touch components on the board.. so I have to remove the 5pin header.. put the wire bus in .. or solder direct or some kind of jumper.. then if I am putting it back.. solder that header back in.   I just tend to find my de-solder skill is ok to salvage a component.. but not if I want to reuse pads again and again....

 

James

wires cut, solder joins.... just a thought....

of course low profile sockets are useful as well...

Edited by _The Doctor__

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This is what I am referring.

 

header.thumb.jpg.3563d3ad7b082dea669595f7c1544d71.jpgdesolder.thumb.jpg.5ea80bc9ca04526836684cba68b12fab.jpgstdinstall.thumb.jpg.bae7f293884ff81f5471981dc0bb5d9a.jpg

 

SO I have the first pictures for the XEL need to desolder.. pic 2 is the best I have managed so far.. and pic 3 is what I need to end up with to test in other board.. or at least get the header out.

 

James

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I don't understand how or why you have the need to solder anything for a UAV.  It should be fully plug & play.  Check my XLD:
 

Bare Board:
38.thumb.jpg.d7af8ea6be3eae16a75e742ac81dd8e2.jpg

 

Plugged in:
59.thumb.jpg.13e42f203972d0b5c687581cc95d0fcb.jpg

 

I can swap this between my 1088XLD and 1088XEL.  Nothing is soldered.  I would say if you need to test in an 800XL, just use a header strip and plug that into the board - or if you already have one in the 800XL, make it pluggable.

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since it's for testing purposes in the 800XL, just stack sockets on the chip side so the header touches nothing.. place a sheet of card stock credit card whatever to prevent shorts if worried in your XL... since you are just testing it should be fine...

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managed to screw up the 800xl now.. no colour. Out of energy for this for now.. very frustrating.

 

James

 

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OK miswired the colour signal into the UAV.. that has been correct.. BUT . BOTH UAVs.. work fine..

 

good UAV rev Ds.. but not for my 1088.. which is still messed up.. and its not the UAV.. but it is going to the video circuit.

 

So something feeding into the UAV is not right on the board.. How to I isolate that?

 

James

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I would go back and check for a short between the pins on the GTIA.

First remove all LSI chips, then on the GTIA check for a short using a DVM between pins 1-2, 2-3, 3-4, ect...

Wouldn't hurt to check 1-40, 2-39, 3-38, ect. too...

 

Edited by AtariGeezer

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Well.. everything back together..  the display is not as bad as it was. The display in composite is bad in the U1mb menu..   bad.. but in the atari screen not bad. In S-video much better in both. But I think connections etc.. are better now and I can live with the composite and the S-video is of pretty good quality.

SO I can use headers and output to Component? Would that be better than S-video? 

 

I am going to consider this part of the build successful now.. if I can do something to improve video later.. so be it.

 

Thanks to all who contributed and put in suggestions.. it was frustrating.. I guess a so so connection somewhere.. the display is "better"

 

Oh can I use that Stress tester for Altirra for real hardware.. would that be a good way to BURN in the computer???

 

James

Edited by Bikerbob

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did the chip you mentioned stop running hot? if it's still running hotter than it should I wouldn't consider the case closed but rather more of a slowly sizzling lit fuse working towards permanent damage...

 

not something to look the other way on for sure...

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Hi,

I want to connect the MIDI XEL II (with Dream Blaster S2) to 1088XEL and it is a little bit confusing to me.

 

1) Regarding SIO - do I understand that I should connect PINs belonging to the following headers?

MIDI XEL II J1 PIN 2-7

1088XEL J5 PIN 2-7

 

2) Regarding AUDIO.

MIDI XEL II J2:

PIN1 - /RESET

PIN2 - LEFT OUT

PIN3 - GND

PIN4 - RIGHT OUT

PIN5, PIN6 - LED

 

Where do I connect "PIN1 - /RESET" ?

Where do I connect PIN2, PIN3, PIN4 ? The AUDIO header on the XEL 1088 board has only OUTPUT pins :(

Can I ignore pins: PIN5, PIN6 ? What is the purpose of this LED ?

 

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2 hours ago, TheMontezuma said:

Hi,

I want to connect the MIDI XEL II (with Dream Blaster S2) to 1088XEL and it is a little bit confusing to me.

 

1) Regarding SIO - do I understand that I should connect PINs belonging to the following headers?

MIDI XEL II J1 PIN 2-7

1088XEL J5 PIN 2-7

 

2) Regarding AUDIO.

MIDI XEL II J2:

PIN1 - /RESET

PIN2 - LEFT OUT

PIN3 - GND

PIN4 - RIGHT OUT

PIN5, PIN6 - LED

 

Where do I connect "PIN1 - /RESET" ?

Where do I connect PIN2, PIN3, PIN4 ? The AUDIO header on the XEL 1088 board has only OUTPUT pins :(

Can I ignore pins: PIN5, PIN6 ? What is the purpose of this LED ?

 

Go to the MPBI on the board.

 

There you will see:

/RST = Reset

/L-IN = Left audio IN

/R-IN = Right audio in

GND = GND (you can also get this at various points on the board, but since you are connecting three other pins here . . . .

 

Yes, you can ignore the LED pins.

Screen Shot 2019-09-14 at 06.42.35.png

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What I meant is the LED provided by the Realan 80 case.

On the picture below it is not connected at all:

 

2vhFqxk.jpg

 

I though it would be nice if the LED would present SIO activity, but the J3 header has seperate PINs for READ/WRITE activities.

My guess is that it should be safe to connect it to PINs: 5 and 6 (SIO READ).

Does it make sense?

 

Edited by TheMontezuma

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Yes connecting to 5-6 (SIO RX) of header J3 should work, although you might want to try pins 7-8 (SIO TX) as a comparison to see which one you like better. And if you ever install a XEL-CF3 the diagram below maps out where the HDD LED could go as well (CF Activity).

 

XEL-CF3_connect.jpg

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41 minutes ago, TheMontezuma said:

I finally connected the MIDI board (with S2 Dreamblaster) and prepared an ATR with the player and example midi files from:

https://ataribits.weebly.com/midi.html

 

I can hear the MIDI sound only in the right channel (although the Stereo POKEY works OK).

 

Is it normal ? Or is it my Dreamblaster damaged ?

 

The MIDI files I have been using are definitely stereo.  This is in my 1088XLD so I am sorry I can't provide help with possible wiring or connection issues in the XEL.

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I think I found a reason for my problem with S2 Dreamblaster and I'm afraid it is a bug in the layout of the MIDI XEL II board :(

 

The MIDI XEL II diagram is OK and it shows that both audio channels (and /RESET signal) are expected on the same side of the M1 header:

 

s2_0.thumb.PNG.a3542713eac191df9eb3e9dfc1120bf9.PNG

 

S2 Dreamblaster diagram and board are consitent with that:

s2_1.thumb.PNG.1004b5c3c65d49908e10721a4590778d.PNG

s2_2.PNG.5e76f78153337e60d66bc2ee0c5b35bd.PNG

 

 

Now we take a look at the files uploaded to the OSH park:

 

midi1.thumb.png.8bb9906c5a6e98b73c197ecd5265de17.png  midi2.thumb.png.612c2866b0056ada7623d3ad06f3e9d8.png

 

What we see is that the left channel is on the opposite side (SOLDER SIDE, the second PIN from the down side on the left).

It is exchanged with the GND. Picture on the right side shows that right channel and the /RESET are OK.

 

Has anybody tested it before? Perhaps I'm wrong?

 

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So far the theorie.

Now the practical part.

I have just corrected the connection (unsoldered both PINs and soldered a connection for the left audio channel with a flexible wire. GND is anyway bridged, so no need to solder extra GND) and voila - music on both channels.

 

IMG_20190917_220600.thumb.jpg.5ee37882b06dbbbc22fb27c1b07b557c.jpg

IMG_20190917_220510.thumb.jpg.b09a4743dbde0a62b7a59d8ae359158c.jpg

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1 hour ago, TheMontezuma said:

A picture tells more than 100 words:

 

error.thumb.png.fa0d3ae9ad46548d86e3f3bdfc502c4d.png

 

The two PINs marked in red are incorrectly exchanged.

Best ping @mytek and let him know.

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Arggg!!!! I thought I had completely tested that board, but obviously not. Just looked at a couple of boards over here and yep -- screwed up :_( .

 

I'll have to deactivate the links on my website for those until I have had time to correct the files and get some sample boards to test.

 

So sorry you had to be the one to find this.

 

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