| Main > Project Announcements |
| Vector-gasm... Cosmic Chasm! |
| << < (5/23) > >> |
| bobbyb13:
Arroyo! Good to see you come up for air. I appreciate you chiming in on the mess I'm making. It is obvious I have a little editing to do and I'm happy to hear what I am doing wrong at any point. Of course if I knew that you were at this same endeavor I wouldn't have bothered posting my hack work! :lol I did actually have some time to do a little harness building today for the next one. I am curious to know what the wiring situation for those heatsink cooling fans is since the set I have of course didn't come with any instructions. I'll take a shot at posting some pictures here once my work day is finally over. |
| Zebidee:
Nice work Bobby! Was hoping to see a vector build post. I've been lurking on Barry's FB group and noting your participation. |
| bobbyb13:
Sadly at this point my participation is mostly begging for help to get AdvanceMame to recognize my spinner! Thanks Andrew. I've been wanting to get at this for a while now. Of course this may be an exercise in futility because this otherwise choice tube has a bonded yoke and no adjustment rings. Not the best thing to be working with to try to instill confidence in anyone really since every other set I have cracked into was far easier to deal with. But anyway... Last night I stayed up far too late (can't help myself) and rewound the ferrites for this yoke. I had no choice here, but leaving the yoke on is a great idea I think. This thing had some spacers that both hold the ferrites off the yoke body and also direct how the windings can group. I did not rewind this exactly as it was done originally, but opted to space the wire out as evenly as I could. It may not work right like this but I will try it this way first. After I had it all back together the resistance value of 0.6 I got was what I have seen work on my other build so I figure maybe it will be ok here too. I spent a little time building harnesses and doing layout while I was stuck on the phone today. Hopefully the vga connectors I ordered get here soon, as the earlier version of the board I have here for this build doesn't have a vga plug, so I need to solder one up. The rest of these connectors are really straight forward molex kk style ones and I believe that the kits come with all of them required. Like I said, both of the ones I have here I got second hand (impatient waiting on the one I got in line for a while back!) so I can't be sure of what they were originally shipped with. If you include the power supply, there are only 4 parts to this whole thing apart from the tube and yoke. The degauss posistor board, which I have opted to run line voltage from my power distribution block. It should be fused on the line side of course. I have used a 5 amp fast blow and had no issues. The high voltage unit gets its power from the deflection board through a 4 pin molex connector and has the neckboard (which I suppose I should have taken a picture of) already attached here. There is also a 3 wire connector out to feed the deflection board fans but I am not sure if the third wire is a signal wire or what. Help Scott! ;D It is also the only one of the components that needs to be grounded to the tube. There is a through hole on the front corner to solder to. The deflection board has the most activity on it. I don't believe the original Amplifone boards had any active cooling system so this beats that already, and I know the current versions of this kit include an even more massive heat sink but no included fans. Not sure what temperature those transistors are happy to run at for a long time but I have read 175 F on the other newer heatsink right next to the transistors so that could probably benefit from a fan too, even if it isn't attached directly to the heatsink. The other parts of these boards appear the same no matter which version you might have. Everything is very well labeled so this is rather redundant, but... Connector for HV unit is the one upper left. The one lower left goes to the neckboard. It's important to make sure you follow the printing on the board mask because I know on one of my kits the wires cross in that harness. The connector in the middle of the board is for the yoke, one pair left, the other right. Video signal is the one on the bottom middle. I need to dig up a diagram I found of how this should be soldered to that vga connector to mate with the DVG properly. When my connectors show up I will post that too. Finally is the power header on the lower right side. This was the part that scared me the most because I didn't want to blow anything up- and I immediately thought I had. It requires +24VDC and -24VDC. The board literally uses one leg to send the beam one direction, and the other leg to send it the opposite way. I believe it is the positive sends the beam right on the X axis and up on the Y axis and the negative sends it left on X and down on Y. If you think about it, that makes troubleshooting issues easier as things will fail in halves or quadrants. Cool stuff. So really all you need is two 24 volt DC power supplies. The +24 one you wire normally and you swap the positive and negative wires from the other supply to feed the -24 side. That is it. You don't need any crazy toroidal 50VDC center tapped transformer to get this to run. That said, still the first problem I had was outsmarting myself and mixing the wires on the harness and sending +24 V to both sides of the board. Remarkably (and thankfully) it didn't kill anything. It wouldn't, it just sends voltage that the board can't properly amplify the signal of to get full deflection. If you sent a lot more than 24VDC then you might blow stuff up of course (I recall one reply from Fred saying that you could probably actually send the board 35 VDC and it could handle it.) More voltage, more ability to amplify it and make for a wider image. No idea what the threshold for that might be for screen size, but I do know that Barry said he intentionally was sizing things on the later board kits to mimic the ability of a 25" Amplifone. That is the dream of course. And all this explains why the first image I saw was just this cute little 1/4" wide winking ball in the middle of the screen. The board was unable to deflect anything one direction because I had given it the wrong polarity of voltage to do so. As far as the other axis being squashed, I hadn't realized yet that I had wound the ferrites in opposite directions either. Hence the little ball of no deflection. And even after I had corrected my first obvious failure and finally sent proper voltage to the deflection board, all the cross wound yoke did was squash the picture into this 3/8" horizontal line in the middle of the screen. It also made the flyback screech to raise the hair on your neck so I shut it off fast and tried another yoke, which I accidentally wound properly the first time! Now I know. As soon as my other pair of power supplies and vga connector get here I will finish the bench build of this thing and fire it up and see what we get. Should be interesting given this yoke situation. :dizzy: |
| Mike A:
--- Quote from: bobbyb13 on March 06, 2023, 11:46:42 pm --- Of course if I knew that you were at this same endeavor I wouldn't have bothered posting my hack work! --- End quote --- You are doing good work. I love to see this kind of stuff on BYOAC. |
| PL1:
--- Quote from: bobbyb13 on March 07, 2023, 03:11:12 am ---There is also a 3 wire connector out to feed the deflection board fans but I am not sure if the third wire is a signal wire or what. Help Scott! ;D --- End quote --- You guessed right. It's the tachometer sensor wire. A protective shutdown circuit plus a 3-pin fan is a good design choice for applications like this where overheating due to not enough air flow can cause severe damage. Scott |
| Navigation |
| Message Index |
| Next page |
| Previous page |