|
Post by km987654 on Aug 26, 2020 4:29:22 GMT -5
Title says it all. If you have one to sell please message me. Hadn't realised how long ago I made this post. Where did that go? Still happy to hear from anyone with a Moome card to sell. That's for Barco. Can be internal or external. Happy to hear from anyone that might have tried another HDMI to VGA or RGB box that has worked well.
|
|
|
Post by km987654 on Jun 13, 2020 1:16:39 GMT -5
Bump
|
|
|
Post by km987654 on Jun 4, 2020 1:51:44 GMT -5
Well, bandwidth measurements kind of the hardest, as it needs good understanding how the measurement setup affects the shown results, but don't panic, there are several great articles about the art. This is one of the best, for you, mostly the beginning of the artilce and the appendices are the most interesting as it deals with oscilloscope behaviour and proper probing techniques.
As for oscilloscopes: one of the most popular (analog) high bandwidth oscilloscope family is the Tektronix 2465 no suffix/A/B with bandwidth respectively 300/350/400MHz, these are very generously specified as all of these easily outperforming the advertised bandwidth specs, has digital readout feature and two full featured channel, and two additional channel with limited input (voltage) range. These are great scopes, and not extremely expensive, but as a high performance units their age (~30yo) is slowly starting to show its signs. Capacitors needs to be replaced allover the place, and more specifically (depending on revision) these scopes also contain a DALLAS chip to retain calibration constants, once the battery depletes the constants are lost. So backing up the DALLAS chip content is essential. While recalibration is also possible, it requires a very specific toolset to perform, and it is not very easy nor cheap to come by, but there is a huge fan base of this family of scopes so the community power can help a lot, but it is definitely a hassle. Tektronix 2445 was a lower spec (150MHz) sibling of this family but it is also a very great instrument, often performing well over 200MHz: SeeA vintage classic is the Tektronix 485 (350MHz), while old (~40 yo.), but it is built like a tank. With digital: they had their TDS5xx/6xx series, they are similar vintage to the 2465, so they equally suffer from bad caps, and calibration is only externally possible
Hewlett-Packard is an other great oscilloscope manufacturer, their fully analog scopes topped at 275MHz bandwidth, 172x model series, myself have a HP 1720A model. With digital scopes they have a wide selection: HP 54542 or HP54641/2 are good example, the nice thing about the HP digital scopes is that they can self calibrate, that is you just have to connect a single coax cable from the back to the front and run the self cal routine, very convenient.
There were other manufacturers for high bandwidth analog scopes like Philips and Iwatsu, but these are rare (along with spare parts and knowledge about them).
In contrast you can buy a brand new Rigol DS1054z oscilloscope for under 500 EUR, that is a 4 ch 50MHz digital oscilloscope (which can be easily software hacked to 100MHz bandwidth), this would not be suitable for bandwidth measurements, but for everything else yes. A brand new Peaktech 1275 (2 ch, 300MHz) scope is about 1500 EUR, a Rohde&Schwartz RTC 1k 302 (2 ch, 300MHz) digital oscilloscope is about ~2100EUR
Well it seems I have come to the right place or at least person for oscilloscope info. This info is more than I expected. Thanks.
|
|
|
Post by km987654 on Jun 3, 2020 17:27:51 GMT -5
Thanks for all your input. I have no knowledge of what would be necessary so your information has helped a lot. I will see what's around and how much it is. I am just getting started on this avenue.
I am not in any hurry so can I wait for a deal on something. Perhaps a cheaper analog scope for bandwidth measurements to start and see where that takes me.
|
|
|
Post by km987654 on Jun 3, 2020 2:58:51 GMT -5
What specifications should I look for in an Oscilloscope for CRT projector?
|
|
|
Post by km987654 on Apr 20, 2020 20:41:21 GMT -5
If anyone has any 909 RGB end stage amps to sell then please contact me.
|
|
|
Post by km987654 on Nov 25, 2019 3:43:42 GMT -5
Hello, Yes I did, I even used the EPROM from the fully functionnal controller, and it's still the same. I tried having a look with a logic analyzer the SEMU<->Controller parallel communication, but that's pure binary, not human-friendly at all ; I won't be able the dig this way. Something else is different from these generations of controllers.. Robin Yes thats what I am also saying. You need a controller that already has the J20 connector.
|
|
|
Post by km987654 on Nov 25, 2019 0:21:05 GMT -5
Finally got my J20 mod on the older controller working : after some checks, it was not outputing one of the signals, because I missed a connection on the SN74AC74 and left the "/Set" input pin unconnected... (should be on Vcc) So it works well with the 808S SEMU, but is still incompatible with the 909 SEMU, I don't get what's different. At least with the controller, I don't have anymore the PLL issue and can work at 45+KHz H frequencies. Robin Hi Robin Are you using firmware 7.61 and RWI 5.09? If so and its not working then perhaps it has something to do with the controller as it did not originally have the j20 connector so perhaps its not the same as one that does.
|
|
|
Post by km987654 on Sept 22, 2019 3:31:18 GMT -5
Hello Keith, Not finished, but just on hold. Not withdrawn at all. I focused on other activities while the weather is good, I'll be fully back to it during Autumn. The projection room at my friend's, isn't ready at all also, and won't be soon. Last thing I did was trying to attach these video amp, to a large horizontal bracket ; tried to cut it my (home-made) CNC, but failed as it is too weak to work aluminium (I didn't made it for such work, only PCB drilling). As is, these video amp are too loose, they fall easily. Still wonder how I'll attach them ; keeping the blue and red tube centering movement. I'm probably overthinking. Robin Good to hear that you are still working on this Robin. I have also been guilty of overthinking solutions. Einstein said it best "the simplest solution that solves the problem is usually the best" something I usually fall back on.
|
|
|
Post by km987654 on Sept 21, 2019 4:31:16 GMT -5
Did this project ever get finished?
|
|
|
Post by km987654 on Sept 4, 2019 6:32:33 GMT -5
What is it? It looks like a circuit of a frame. But it is not that of a 1209s. What should I check? Thats a 808s frame but the 1209s also has a scan fail circuit. You need to check all of the boards in the scan fail circuit.
|
|
|
Post by km987654 on Sept 3, 2019 4:28:36 GMT -5
Did he ask for pictures before buying?
|
|
|
Post by km987654 on Sept 3, 2019 4:26:03 GMT -5
He can try to disconnect the HT leads to the tubes, and let only the red one for example, then only the blue, then only the green. That we will check that no tubes are shorted. Just tried, same issue. See this.
|
|
|
Post by km987654 on Apr 3, 2019 3:27:01 GMT -5
Title says it all. If you have one to sell please message me.
|
|
|
Post by km987654 on Mar 18, 2019 1:30:55 GMT -5
So as I'll forget 3D for this project, I got a very nice set of P16LXW tube, so I retubed my first set with these : I had to turn the G2 near minimum, comparing to the previous one, they are bright However, I reach the maximum on focus setting (99), and can't move back the focus coil enough to solve that. The tubes are not in fault, but as I've put the 120MHz video amp, its support is interfering here. There is very little play left. I think I'll cut some back of the focus coil (plastic support part) You shouldn't need the support brackets for the RGB amps. Take those out and you can move the focus coils further back. This still may not solve the problem. You may need to have look at how your CPC magnets are setup.
|
|