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nauseous

Aussie Arcade Member
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  1. Well some good news... I put the A2M6021x back together and started on the next one to be repaired. Model on this next monitor is A2M2056x - to my surprise it is the same exact same chassis as in the A2M6021x just with a Samsung Tube instead (chassis numbers match). So I have swapped chassis over and now have one working monitor. Needs some fine tuning but my work on the first chassis was not wasted. I tried to remove the neck ring / purity rings from the A2M6021x in a hope to get at the yoke... The plastic has perished and is brittle, i snapped a retaining tab off that holds the rings in place. So be very wary if you do try go down this path. I'm sure one could easily 3D print a replacement retainer.
  2. Hey all, I fitted the replacement TA7644BP IC over the weekend. Monitor works apart from a geometry fault... One of the winding's on the deflection yoke has gone open circuit. The top half of the monitor is mushroomed in... Looking closer at the yoke I can see green corrosion which I missed initially when tearing it down. Not sure exactly what my best options to move forward are at the moment. Apart from finding a working replacement yoke... What are my chances of successfully re-winding this coil by hand?
  3. Very nice. Do keep us posted with how you go. I am awaiting a replacement TA7644BP IC before I can continue with the one I have... And also you are correct with the Value of C101, I just double checked my notes and I wrote it down initially as 47uf 50v..
  4. Got a little further with this over the weekend. I am suspect that the TA7644BP is faulted. It looked dubious when I first opened the case.. The earth strap on the back of the monitor had disintegrated and made a mess of the chassis. Subsequently I cleaned the chassis and replaced earth strap (plus a few other components). The picture on screen comes and goes at random, when it is visible the adjustments make no difference to the display (brightness, contrast, v/h hold, size). Last night digging around on the internet I have found that the Samsung 20K20 chassis is almost identical to this model Apple. Same IC's, very similar internal wiring, even to the point it has a 3 way service switch. Mind you being a TV set it has extra circuitry for the tuner portion, but this is drawn separate to the actual CRT workings. I'm sure there will be subtle differences between this and the Apple monitor so use it purely as a guide to aid you in troubleshooting. I am doubtful that component labels/values match exactly. Here is a link to the schematic https://elektrotanya.com/samsung_20k20_chassis_mtc_mtv207r.pdf/download.html
  5. Switch does appear to orientated correctly. Just spent a little bit more time and went over all the pots to get those stuck moving again. I can hear the monitor's EHT come on, but the screen just stays black. I guess it's time to double check the adjustment pots...
  6. Very similar to before replacing capacitors (was hoping this would have resolved fault - but clearly something more going on). But that's OK as at least all of the above are now ruled out. You can't really see in the photo but the monitor is showing output. APPLE II and the console prompt is visible but scrolling. Just working on getting a complete list of symptoms at the moment. Some of the adjustment pots look to be dirty / stuck. Would it make any difference driving this from a Apple IIe (currently testing with a Apple +) ?
  7. I just went through and re-capped one of these monitors overnight, thought I might put this here for future reference. Capacitor List: C390 - 50v, 47uf C211 - 50v, 1uf C135 - 50v, 1uf C130 - 50v, 10uf C102 - 16V, 100uf C111 - 16v, 10uf C203 - 50v, 0.47uf C213 - 50v, 0.47uf C309 - 35v, 470uf C218 - 50v, 0.47uf C138 - 25v, 1000uf C209 - 16v, 100uf C117 - 50v, 0.47uf C136 - 16v, 1000uf C120 - 50v, 0.47uf C220 - 16v, 47uf C305 - 35v, 470uf C302 - 25v, 1000uf C312 - 50v, 10uf C310 - 35v, 22uf C308 - 50v, 1uf C161 - 25v, 47uf C501 - 400v, 220uf C502 - 160v, 1uf C505 - 100v, 0.47uf C503 - 50v, 1uf C101 - 50v, 47uf C509 - 160v, 220uf C224 - 160v, 1uf C201 - 50v, 1uf C140 - 250v, 22uf C908 - 250v, 1uf (Neckboard) *Edited 05/06/2020 to update correct value of C101
  8. Hi Guys, I have a bunch of Joystick "Extender" cables I would like to get rid of. Apparently they are left over's from a failed MAME project. From my understanding the project was so that you could connect an original controller to MAME. I know nothing more about the details as I wasn't involved. So in total I have 5 different types of tails available, see attached photos. SNES N64 DB9 (Atari, c64 etc) PlayStation2 (PS2) Dreamcast. 50c Each 20 Cables - $5 (Your Selection) 50 Cables - $10 (10 of Each type) Hit me up if interested. Cheers,
  9. Another update from my end. SDisk II interface arrived, I assembled it and it works as expected. This has allowed me to load troubleshooting tools and get 2 floppy drives working. Mixture of bad IC's, bad floppies and repeated dirty heads. I'm moving onto a lot of 5 or 6 Apple IIG's next, this time I will make a better effort to document the fixes. Good news so far is no battery damage on any of the motherboards.
  10. I managed to track down a cheap SD II Interface board that should be arriving this week. That will finally let me get to the bottom of this floppy situation. In the meantime I have managed to get 7 out of the 8 machines returned to operation. Confirmed only 1 dead MMU and 1 dead IOU chip, plus a bunch of failed cpu, rom and ram ICs that had to be replaced. Just in the final stages of re-assembling the last 2 machines now. Not a bad outcome. Clones are still pending parts from China for the power supplies before I can start troubleshooting them (not a standard apple power plug on m/b).
  11. Well that is encouraging what you say regarding the custom IC's. In the 4 boards I have the IOU ic's are all soldered in, I have removed the 2 that I suspect might be at fault and am now just waiting on some 40pin sockets to arrive (all out..) Once they arrive I can start swapping chips around into known working board to see what I get. One of those IOU's failed to give the reset signal from pin 15 to the 6502 CPU whilst in board. The reset line appears to be dead coming from that IOU chip. The other failed to give graphic output / video timing - I'm hoping this isn't IOU related. Will update when I know a bit more. Still having no luck with the Floppy Drives and reading media. Basic maintenance has been performed, as well as adjusting motor speed to be roughly 60hz. Drive 1 (Disk II): Dead MC3470AP - Doesn't appear in Volumes list under ADTPro. Drive 2 (Disk II): Everything appears to check out OK on Oscillopscope, . Cant Read Disk (I/O Error), Can't Write Disk (Disk faulty or Check Drive Door) using ADTPro. Drive 3 (Rana Systems - Elite One): Doesn't appear in Volumes list under ADTPro. (Yet to be troubleshooted) I have a few more drives I can test with yet... If I could just get one to work then I might have a path to get the others working.
  12. OK So a bit more progress. ADTPro requires 64bit Java, with this fixed I have been able to send data via the Super Serial II Card and load DOS. This makes testing easier, via serial I can push data at 115200 baud. So onto repairing drives, I have found a few good pages regarding DISK II repairs, but for now I am going to follow "Sams - Computerfacts" repair book. https://mirrors.apple2.org.za/Apple%...Apple%20II.pdf This page also looks like it might have some good tips. http://www.apple2faq.com/knowledgebase/recalibrating-disk-drives/
  13. Thanks D.C - So far I have had a pretty good run with the machines but I suspect now some of the Custom IC's in the 2e's are at fault. I don't like my chances of finding replacement IOU/MMU IC's. In all I have got 5 out of 8 machines booting up to display Apple ][. Lots more work to go yet troubleshooting. The Europlus is on hold waiting 74LS153 order, but the II Plus is working again. Like you said I got it to boot with just the first 16kb of RAM, then started adding banks back one at a time, including the language card. And I also replaced all filter capacitors in all 8 power supplies - these appear to be testing good now. I grabbed out 2 floppy drives (Apple Disk II) and 2 disk controllers to try with ADTPro, along with the Super Serial II card. I am having issues with my windows 10 laptop not detecting the COM port in ADTPro - so I haven't been able to bootstrap via serial connection. And both drives fail to read/write to a disk but both controllers appear to work. So at the moment I am a bit stuck, I am hoping the calibration guides online might help get one drive to a working status again. And thanks Jedi/Arcade King for the offer. Arcade if you don't mind I might just take you up on the offer of a loaner.
  14. ADTPro worked OK via Audio, system booted up with it. But I couldn't find anyway to transfer a DSK into RAM. Converting the Diagnostic Disk (*.dsk) to a mp3 and playing it over the audio jack returned an error. I only used the "LOAD" command and played it back. The machine was reading data but after a while of playback returned ERR.. And I appear to have corrupt RAM on board in the upper 16k region somewhere. I have found a Super Serial 2 card in one of the machines, but it still looks like I might need a floppy drive attached to go further now... I can't see any other way of booting a dsk at the moment..
  15. Is the super serial card and disk drive required to run diag tools or just to load the diag util? I was hoping I could convert a disk image to wav/mp3 (https://github.com/datajerk/c2t) and load in via cassette port. I have read i can bootstrap the machine using ADTPro over Audio. I also found this while searching - http://www.willegal.net/appleii/appleii-kb-int.htm - worse case I can load in data via the Keyboard port on m/b.
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