1088XLD - Custom A8 Computer in 1050 Drive Case

[+MacRorie]

8 minutes ago, towmater said:

Is anyone selling pre-programmed microcontrollers? Even if I manage to build the 16F1847 joy-port programmer I'd still need to figure out the 12F1572. It seems sort of wasteful to buy and build a bunch of kit just to program three IC's.

 

Sure.  I can sell you just the pre-programmed PIC chips.  However, the PIC2JOY-STIK will program all 3-4 chips, no fuss.  Just let me know via PM or email macrorie@thebrewingacademy.com

-M

[rockdoc2010]

I just fired up my 1088XLD and I get a eight note musical rif but my screen is blank. Color filled, one color adjustable by the pot, but nothing is loading from U1MB. I hear a slight sound when I hit F12 or F11 but I am getting no action on the screen. Its a great looking single color screen btw.

I used Sdrive max on my XEL in order to do all of it's updates; U1MB firmware, XEL-CF3, and SdosX but I am stuck on the 1088XLD.

I have changed out Sally Antic Pia And GTIA and the SRAM

 

MIDI works and color renditioning of the background works but I get no boot up. No beeps other than the midi intro tune

Any suggestions

[chevymad]

Just about done with my XLD and realized I have the smaller 9v power supply for a 400. I have the 50 watt coming, but will the 400(18.5 watt) one be enough to try it with just uav, no other options yet? I do have a 10.5v ac 1amp supply as well, but will that be too high a voltage?  Also, what jumpers need to be in place? 

[+DrVenkman]

8 hours ago, rockdoc2010 said:

I just fired up my 1088XLD and I get a eight note musical rif but my screen is blank. Color filled, one color adjustable by the pot, but nothing is loading from U1MB. I hear a slight sound when I hit F12 or F11 but I am getting no action on the screen. Its a great looking single color screen btw.

I used Sdrive max on my XEL in order to do all of it's updates; U1MB firmware, XEL-CF3, and SdosX but I am stuck on the 1088XLD.

I have changed out Sally Antic Pia And GTIA and the SRAM

 

MIDI works and color renditioning of the background works but I get no boot up. No beeps other than the midi intro tune

Any suggestions

The MIDI tones are merely a little easter egg in the PIC chip that drives the S2 wave blaster synth module. It doesn’t actually indicate operation of the computer. If you’ve built and installed the level 1/2 I/O boards, you can toggle the MIDI CLOCK switch and turn off the boot up tune. 

 

A solid single-color on boot is usually a sign that ANTIC and GTIA are working but the system is not booting up properly. In a vintage A8, it’s often the OS ROM chip, sometimes the MMU or a DRAM chip. So if you don’t have a scope to measure signals, you can start with some basic stuff - ensure you’ve got the U1MB installed properly - it’s sometimes possible to inserted it down into the XEL/XLD boards offset laterally by 1 pin location. In other words, it looks like it’s installed properly but it’s shifted to one side or the other such that the unit isn’t inserted into all the headers. So verify that.

 

The base 64K ram still has to work properly for the machine to boot, so check your SRAM and if you have a spare, try swapping it. Check that you’ve got all the 74 series logic chips inserted correctly, no bent pins, nothing inserted backwards ... Finally, based on personal experience with my own beta XLD build, make sure you’ve got all your discrete components inserted correct way around, especially the diodes in the clock circuit. Two of them are oriented one way, the third is oriented the other - that tripped me up for 4 days after I finished my board before I saw the problem.

[+DrVenkman]

7 hours ago, chevymad said:

Just about done with my XLD and realized I have the smaller 9v power supply for a 400. I have the 50 watt coming, but will the 400(18.5 watt) one be enough to try it with just uav, no other options yet? I do have a 10.5v ac 1amp supply as well, but will that be too high a voltage?  Also, what jumpers need to be in place? 

You have to have the U1MB installed as well but it will probably be enough for a basic boot test.  Don’t use the 10.5V supply. Theoretically the voltage regulators can handle it but not worth the risk. I don’t have my machine open or build photos handy re any jumpers but you have to have at least the NTSC/PAL jumper set. 

[chevymad]

Tried the 400 power supply. I don't have a video cable made yet and with only UAV installed I need to make an Svideo connection, but I did plug the audio cable in... and nothing.  So I went over everything I could see, touched up a few places then mounted the IO boards on their standoffs. Do those boards ground through the standoffs?? Anyway, after doing all that, tried again and I'm hearing the Atari fart!! So now to build a cable. I'll probably be moving my VBXE from my XEL to this machine too. Since it's easily installed internally, vs my other machine having it laying on the desk.

[_The Doctor__]

THAT'S NOT A FART,  It's the Chirruping and Purring of a HAPPY ATARI CAT!              :)

Edited April 18, 2020 by _The Doctor__

[chevymad]

Pics of my red build. I have the wrong height header for the io board at the moment. Will have to make that change when new part arrives. Also waiting for a PokeyOne for the 2nd pokey. I've stolen the U1mb and pokey out of my 800xl for now. Think I'll leave my original Candle U1mb in this machine. Which pokey can be the pokeyone? Left or right? 

Edited April 19, 2020 by chevymad
adding to

[+Stephen]

I love seeing more and more of these 1088 boards come to life

[Kyle22]

I want one, but my main goal is to replace my 300Dt with 296K miles that blew the chain. It's my fault. I knew I should have replaced it a long time ago... :(

 

At some point, I'll buy it, but not just yet.

 

:)

 

[+DrVenkman]

1 hour ago, chevymad said:

Which pokey can be the pokeyone? Left or right? 

The right only. PokeyONE does audio only. SIO and keyboard stuff is part of the Left POKEY functionality.

[chevymad]

I knew only 1 could be, but wasnt sure which. When I didn't get any action the first time, I stole the pokey out of my 800xl to fill the 2nd slot.. I'll put it back when the pokeyone get's done with it's US tour. 

[chevymad]

Ok.. working on getting video. I have something I think really odd going on. I only have the single 3.57 crystal in X2 position. With the NTSC/PAL jumper in the left position, I get a rolling static filled screen. With it in the right position I get video. Also in the left position, after the Atari fart noise I get feedback. But in the right position it does the atari fart and silence. But isn't the right position PAL??? This is with composite video. 

[+mytek]

 

1 hour ago, chevymad said:

Ok.. working on getting video. I have something I think really odd going on. I only have the single 3.57 crystal in X2 position. With the NTSC/PAL jumper in the left position, I get a rolling static filled screen. With it in the right position I get video. Also in the left position, after the Atari fart noise I get feedback. But in the right position it does the atari fart and silence. But isn't the right position PAL???

Check the oscillator section.

 

Specifically look to see if D3, D4, and D5 are all in the correct orientation. Notice that D3 is flipped 180 compared to the other two.

 

 

 

[chevymad]

Yes, D3 is reversed from the others. The bands on D3 and D4 are towards each other. 

Edited April 20, 2020 by chevymad

[+DrVenkman]

Michael is too kind to point it out but I don’t mind - D3 being installed backward was the only mistake I made during assembly of my beta board, and it took me 4 days, the help of an oscilloscope, and photos of @Stephen’s in-progress beta build to clue me in to my mistake.

 

 

[chevymad]

I saw your troubles, so was allready on the lookout for this problem. Think I have mine right though. I've been pouring over pics of other builds and comparing. Haven't seen my issue yet. I did something similar on my xel build and had one of the resistor networks backwards.

[Simply_Graham]

Dr Venkman you are NOT the only one to have put D3 in backwards ... 

I did exactly the same, however having an oscilloscope I found the problem in about 30 mins.  As  I’d  decided on checking the clocks first. (Mine is a PAL build so no X2 crystal. But does have X1 and  components surrounding U6 and Q2)

However I knew it was the system clock oscillator and it still took me that long to spot my mistake.

[Simply_Graham]

ChevyMad

Try checking the values of R18 & R19 as these should both be 2K2  resistors RED RED RED,  yours appears to be 22K RED RED ORANGE should only need to change R19  although mine look more like Brown Brown Brown in the photo.

Edited April 20, 2020 by Simply_Graham
Added Picture

[+mytek]

1 hour ago, Simply_Graham said:

Try checking the values of R18 & R19 as these should both be 2K2  resistors RED RED RED,  yours appears to be 22K RED RED ORANGE should only need to change R19

Yep the resistors do look to be 22K instead of the proper 2.2K (shown as 2K2), and R19 would be the only one of concern to get the NTSC oscillator working properly, assuming that's all that is wrong. Although personally I would suggest changing both R18 and R19 to the correct value just in case you decide to go PAL later on.

 

Here's the schematic for the oscillator section.

 

 

[chevymad]

Thanks for the clue. It boots up now in the NTSC position as it should.  Still have some issues to work out. Probably need to go through all the resistors and make sure they're right. Instead of ordering specific resistors for this, I had a big bag of radioshack resistors I bought years ago. So I have to go through by hand and identify the ones I need. This time I had the wife verify the colors! lol  I get a nice blue screen with the d1: prompt now. However, on the U1MB screen I have a border flickering with color going on. I get boot error from my sdrive, the power light is yellow even with the cf card adapter plugged in, and I'm not positive bout my Svid cable, cause it doesn't work. Composite works however. Lots of troubleshooting to go yet. Thanks everyone for the help!  Oh and the keyboard sometimes types atascii characters instead of letters. 

Edited April 21, 2020 by chevymad

[rockdoc2010]

WOO HOO!

 

Another 1088XLD is alive and well. After it failed to boot I am pretty sure I messed up the TK-II chip so I reflashed it as well as replacing the HTC logic chips; 174, 08, 138, 4053 and 00.

 

Sometimes a shotgun approach works because it did! I have upgraded to the XLD U1MB as well as SDX 4.49.

 

Now the Sophia C and VBXE are yet to work but at least the BOB and SDrive Max from The Brewing Academy work great. Thanks Marlin!

 

The Sophia runs straight to DVI and I would think that it wouldn't be a problem. My LCD has HDMI as well as component in but my RGB plugs come from a SVID HD-15 to component cable and I assume that they are correct.

I haven't yet tried them with my BOB yet but I will now that I have working systems.

I see that on my XEL there is a 10PIN cable header that I can attach for the Sophia pass thru and I see a difference in the XLD vs XEL pass-through namely the ground connection is not used on the XLD pass-through.

 

Nice to have two 1088' up and running for now!

 

Cheers

[Simply_Graham]

 

Well looks like things are taking a turn for the best; pleased you've both got them working. :):)

 

Chevymad, make sure the pokey you have in the left channel is a good one, I've had one of my pokey's work fine as a stereo 2nd channel but no SIO swapped round and all good .  It may also be worth re programming the TK II, perhaps clearing up the odd characters your seeing. The yellow indicates CF Swap, however this could be 'swapping back and forth' very quickly giving the appearance of being swapped. ALT-N is the keyboard operation for this but thats programming in the TK II.

I take it the keyboard is known to be good?

Wish you luck!

[chevymad]

Keyboard works fine with my XEL. Pokey chip is from a working 800xl with ultimate.. so should work. Thinking of tkII as well. Will try a reprogram tonight.

[+DrVenkman]

7 minutes ago, chevymad said:

Keyboard works fine with my XEL. Pokey chip is from a working 800xl with ultimate.. so should work. Thinking of tkII as well. Will try a reprogram tonight.

Since this is an XLD and not an XEL, you should also probably confirm all the connections and continuity from the jack and the I/O riser all the way down to the TK-II.