macsonny Posted January 27 Share Posted January 27 Hi All, I've been working on an Atari 130XE unit on and off. Essentially the machine used to work and it had a VBXE installed which I was never happy about. Went to install a GTIAdigitizer from #c0pperdragon as I was really happy with the results of the GTIAdigitizer in my 800XL. Anyway, machine has stopped working. I had to desolder the GTIA and put in a socket for the GTIAdigitizer mod and after that was done the machine refuses to do anything. Have tested all the main chips by swapping into my working 800XL including OS, BASIC, POKEY, PIA, SALLY, ANTIC and GTIA. All worked fine in my 800XL. Replaced memory chips (they were only 12 months old anyway). Did a bit of multimeter work and buzzed all the GTIA connectors/vias and all seem ok. I have removed the IC socket from the GTIA chip location and will replace., But before I do that is there anything else I should be testing or doing? Have attached a few photos of my work so for. Thanks macsonny Quote Link to comment Share on other sites More sharing options...
Beeblebrox Posted January 27 Share Posted January 27 @macsonny could you define no booting? Is it totally dead, no signal with your video out via the savo, which will be the only output available at present given rf modulator is gone. (no composite or rf outputs possible). Because you are talking about VBXE and gtiadigitizer, at present are you experiencing the onion booting state when the computer is in the last picture setup. (qeg with VBXE in place)? Quote Link to comment Share on other sites More sharing options...
Rybags Posted January 27 Share Posted January 27 (edited) Bottom left - you generally remove the master crystal in a VBXE install as it's sourced from there. But now you've removed VBXE so where is the system getting it's clocking from? Note the 4.43 MHz one is just for the PAL colourburst. Also - what was the problem with the VBXE? Most people are really happy with them. Edited January 27 by Rybags 1 1 Quote Link to comment Share on other sites More sharing options...
macsonny Posted January 27 Author Share Posted January 27 4 minutes ago, Rybags said: Bottom left - you generally remove the master crystal in a VBXE install as it's sourced from there. But now you've removed VBXE so where is the system getting it's clocking from? Note the 4.43 MHz one is just for the PAL colourburst. Oh - that's such a good point. The board isn't getting 4.43 MHz from anywhere! Thank you for pointing out the obvious! I assume I'll need to replace the surrporting components to the crystal as well right? 1 Quote Link to comment Share on other sites More sharing options...
Beeblebrox Posted January 27 Share Posted January 27 (edited) 11 minutes ago, Rybags said: Bottom left - you generally remove the master crystal in a VBXE install as it's sourced from there. But now you've removed VBXE so where is the system getting it's clocking from? Note the 4.43 MHz one is just for the PAL colourburst. As Rybags says VBXE provides the system clock. (I wasn't 100% sure whether you were saying the system doesn't work even with VBXE in place anymore.) If VBXE isn't present anymore, as a test just pop it back to the VBXE install setup and you should get a working system back. Basically in an XE system, due to the close proximity of antic and GTIA, you can't have both gtiadigitizer AND VBXE in the same system as they get in each other's way. If you want to use the gtiadigitizer you'll need to add back the system clock crystal and add back the resistor(S?) removed in that area next said system clock crystal when you undertook VBXE install, (see the VBXE install instructions). I've installed VBXE in a good few XEs (as well as XL), but not for a while. Edited January 27 by Beeblebrox Quote Link to comment Share on other sites More sharing options...
Beeblebrox Posted January 27 Share Posted January 27 (edited) 6 minutes ago, macsonny said: I assume I'll need to replace the surrporting components to the crystal as well right? AFAIK yup, see the VBXE install instructions and just reinstate. Edited January 27 by Beeblebrox Quote Link to comment Share on other sites More sharing options...
Rybags Posted January 27 Share Posted January 27 Missing 4.43 would likely just mean you'd get black & white display only. The 14~ MHz crystal is central to the computer doing anything. My VBXE install is on 800XL so I don't know what else would have been removed on the 130XE - possibly some passive support components? Maybe consult the install guide for 130XE VBXE and work backwards. 2 Quote Link to comment Share on other sites More sharing options...
macsonny Posted January 27 Author Share Posted January 27 49 minutes ago, Rybags said: Missing 4.43 would likely just mean you'd get black & white display only. The 14~ MHz crystal is central to the computer doing anything. My VBXE install is on 800XL so I don't know what else would have been removed on the 130XE - possibly some passive support components? Maybe consult the install guide for 130XE VBXE and work backwards. So it actually looks like Y1 is what I removed along with a few resistors and capacitors in the bottom left of the board. Y1 is actually 14.187576 MHz according to the schematics for PAL. Does that sound about right? Quote Link to comment Share on other sites More sharing options...
Rybags Posted January 27 Share Posted January 27 Yes. Before Freddie (400/800, most XL) you'd have had a ~ 3.5 MHz main crystal. After Freddie (all XE) you have the ~ 14 Mhz crystal which goes to Freddie and gets divided down to the 1.77 MHz system clock for the CPU. There are some extra components that go there. But I do suspect what goes there could be different depending on board revision and the type of crystal used. Some are the metalic type that sit flush on the board, some are the plastic encased type that mount a bit like a capacitor. I have 2 x 130XE here and an 800XE for possible reference but fairly sure my 130XEs are both the 16 Ram chip type. Quote Link to comment Share on other sites More sharing options...
macsonny Posted January 27 Author Share Posted January 27 So doing a quick google search finding a 14.187576 MHz crystal will be a bit challenging and stupid me threw out the one I pulled from the board. Anyone know a supplier with a link? Quote Link to comment Share on other sites More sharing options...
macsonny Posted January 27 Author Share Posted January 27 2 minutes ago, Rybags said: Yes. Before Freddie (400/800, most XL) you'd have had a ~ 3.5 MHz main crystal. After Freddie (all XE) you have the ~ 14 Mhz crystal which goes to Freddie and gets divided down to the 1.77 MHz system clock for the CPU. There are some extra components that go there. But I do suspect what goes there could be different depending on board revision and the type of crystal used. Some are the metalic type that sit flush on the board, some are the plastic encased type that mount a bit like a capacitor. I have 2 x 130XE here and an 800XE for possible reference but fairly sure my 130XEs are both the 16 Ram chip type. I feel like a real dummy now for not spotting that in the first place. Now I need to source the crystal as I threw the one from the board out. Any ideas? Quote Link to comment Share on other sites More sharing options...
Rybags Posted January 27 Share Posted January 27 The VBXE has one though it's different to the one on the motherboard just about for sure. The PAL 14 MHz ones were hard to source but I think Lotharek must have found a supplier. The NTSC ones... well they practically fall out of trees. Could you just add your VBXE board back in? Quote Link to comment Share on other sites More sharing options...
Beeblebrox Posted January 27 Share Posted January 27 (edited) 39 minutes ago, macsonny said: I feel like a real dummy now for not spotting that in the first place. Now I need to source the crystal as I threw the one from the board out. Any ideas? ah, never throw out custom atari components - especially PAL system crystals. They are hard to come by. The best cheaper source for them is sourcing a pal Atari 2600 junior and salvaging one from that. You'll often find ones on ebay selling for spare parts, where, even if the console isn't working, the crystal will be 99% of the time. Unforunately there isn't a modern pal system crystal equivilent that is off the shelf readily available. There is for the pal colour burst incidentally. Personally I'd reinstate VBXE and leave it. Edited January 27 by Beeblebrox 1 Quote Link to comment Share on other sites More sharing options...
Rybags Posted January 27 Share Posted January 27 I pilfered one from a 7800 for my VBXE - earlier version that didn't come with one. But again the supporting components are possibly different depending on what type you use. Quote Link to comment Share on other sites More sharing options...
hatchcliff Posted January 27 Share Posted January 27 Zooming in on the 3rd photograph, is that a broken track running between pins 2 and 3 of U17? Can't be sure from the picture - but maybe worth checking. 2 Quote Link to comment Share on other sites More sharing options...
+scorpio_ny Posted January 27 Share Posted January 27 9 hours ago, macsonny said: I feel like a real dummy now for not spotting that in the first place. Now I need to source the crystal as I threw the one from the board out. Any ideas? Maybe this would help? Lotharek's Freddy V2 seems to generate the clock signal on its own. Trying to verify this: https://lotharek.pl/productdetail.php?id=233 Quote Link to comment Share on other sites More sharing options...
macsonny Posted January 27 Author Share Posted January 27 1 hour ago, hatchcliff said: Zooming in on the 3rd photograph, is that a broken track running between pins 2 and 3 of U17? Can't be sure from the picture - but maybe worth checking. Great eye! I did check this and buzzed with multimeter. Ended up being a bit of flux on the track. But well spotted none the less!!!! 1 Quote Link to comment Share on other sites More sharing options...
macsonny Posted January 28 Author Share Posted January 28 (edited) I took the 14.187576 crystal from my VBXE and put on board. I then replaced R18 (220 ohm), R26 (2.2k ohm), C32 (18 pF) and C33 (10 pF) per the 130 XE USERS manual for a PAL 130 XE. Ok. Some progress. Rather than a blank screen I'm getting a very distorted screen and it's booting directly into the memory check.I thought maybe bad RAM and I replaced all RAM and but there was no change. Here's the interesting bit. I replaced the two caps with ceramic caps with the value per the manual but the caps in actual manual are not ceramics. Are ceramics ok to use in place of axial capacitors? Also, reading the schematic for the two resistors, they are per above being 220 ohm and 2.2k ohm. However, if you look at the motherboard pics you can see the band colours don't match the schematics. Does any one know the actual value of the two resistors R18 and R26? The last photo is how my board looks right now. Assume there is no polarity on a two pin crystal right? Does this look right to everyone? 130XE Field Service Manual.pdf Edited January 28 by macsonny Quote Link to comment Share on other sites More sharing options...
macsonny Posted January 28 Author Share Posted January 28 This is what happens with a SYSCheck cart installed. IMG_5047.mov Quote Link to comment Share on other sites More sharing options...
TZJB Posted January 28 Share Posted January 28 11 hours ago, macsonny said: I took the 14.187576 crystal from my VBXE and put on board. I then replaced R18 (220 ohm), R26 (2.2k ohm), C32 (18 pF) and C33 (10 pF) per the 130 XE USERS manual for a PAL 130 XE. Ok. Some progress. Rather than a blank screen I'm getting a very distorted screen and it's booting directly into the memory check.I thought maybe bad RAM and I replaced all RAM and but there was no change. Here's the interesting bit. I replaced the two caps with ceramic caps with the value per the manual but the caps in actual manual are not ceramics. Are ceramics ok to use in place of axial capacitors? Also, reading the schematic for the two resistors, they are per above being 220 ohm and 2.2k ohm. However, if you look at the motherboard pics you can see the band colours don't match the schematics. Does any one know the actual value of the two resistors R18 and R26? The last photo is how my board looks right now. Assume there is no polarity on a two pin crystal right? Does this look right to everyone? What you have done reflects the circuit diagram for CA200519 but not the PCB for the two resistors which show as 240R 5% and 1000000R 5% (1M Ohm) This matches the values for CO70025 but there are no inductors present in the timing circuit for CA200519. I can only suggest that you try the 240R/1M combination and see if it helps. Incidentally the capacitors will have been ceramic from the start but they were in axial form, probably for ease of manufacture. Check the clock frequency output of the 14.187576MHz oscillator at FREDDIE pin 2, and that the 3.546894MHz OSC on FREDDIE pin 37 is reaching GTIA pin 28 intact. This clock frequency is used to generate all of the other clocks via ANTIC and SALLY. 9 hours ago, macsonny said: This is what happens with a SYSCheck cart installed. IMG_5047.mov Syscheck video is not apparently working. Quote Link to comment Share on other sites More sharing options...
macsonny Posted January 29 Author Share Posted January 29 19 hours ago, TZJB said: What you have done reflects the circuit diagram for CA200519 but not the PCB for the two resistors which show as 240R 5% and 1000000R 5% (1M Ohm) This matches the values for CO70025 but there are no inductors present in the timing circuit for CA200519. I can only suggest that you try the 240R/1M combination and see if it helps. Incidentally the capacitors will have been ceramic from the start but they were in axial form, probably for ease of manufacture. Check the clock frequency output of the 14.187576MHz oscillator at FREDDIE pin 2, and that the 3.546894MHz OSC on FREDDIE pin 37 is reaching GTIA pin 28 intact. This clock frequency is used to generate all of the other clocks via ANTIC and SALLY. Syscheck video is not apparently working. You are a genius!!! I didn't have a 240R but had a 220R (close enough) and did have the 1M and replaced the resistors and guess what - success!!!! Thank you to all that helped out. If any of you make it to Australia, I owe you a few beers! 3 Quote Link to comment Share on other sites More sharing options...
TZJB Posted January 29 Share Posted January 29 3 hours ago, macsonny said: You are a genius!!! I didn't have a 240R but had a 220R (close enough) and did have the 1M and replaced the resistors and guess what - success!!!! Thank you to all that helped out. If any of you make it to Australia, I owe you a few beers! That is an excellent outcome, 220R 5% may be within spec. of 240R 5% (228R) which it must be as it works. I am glad that you have restored your 130XE to full use. It occured to me overnight whether you took any pictures of the motherboard before you modified it the first time with the VBXE, in order to confirm these values? Quote Link to comment Share on other sites More sharing options...
ACML Posted January 29 Share Posted January 29 (edited) Is the pin circled supposed to be connected to that thick trace or is that a short? Edited January 29 by ACML Quote Link to comment Share on other sites More sharing options...
flashjazzcat Posted January 29 Share Posted January 29 It's supposed to be connected. Quote Link to comment Share on other sites More sharing options...
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