This is taken with my XG-VNB mod, at G1 output. HP 1120A FET probe (with 100:1 divider), HP 1720A oscilloscope, 20v/div, 1080P 60Hz signal out of a GeForce 6600GT video card (the output of the card was measured here) With analog scopes the intensity grading is also carrying information, which you loose on a digital scope (unless it has digital phosphor feature...)
The point is when I started measuring the XG neckboads chasing the bandwidth problems I did not have the FET probe yet only the HP scope along with Tektronix P6105 and P6106 probes. I estimated the bandwidth of the neckboards to be around 30MHz based on the resolutions I tested on it -by eye, measuring on the output with the Tek 6106 probe showed 5ns rise time (~70MHz), later I got the HP FET probe and remeasuring the the same board gave 12ns (~30MHz) rise time then. And this was pretty much the case with every other stage when I used the Tek probe... On ebay you can find 3-4-500MHz passive probes with one single HF trimming element, the Tek 6106 has 5 of them, yet the tip capacitance make too much disturbance to make it useless for most HF measurements. The HP FET probe in its bare form can take only +/-0.5V signal maximum and has a tip capacitance of 3pF shunted by 100kOhm, you need passive dividers (10:1-> +/-5V, 100:1 ->+/-50V) for higher voltages, using the dividers makes the input to 1MOhm shunted by <1pF. You may wonder why is this high impedance head if it only 100kOhm or 1MOhm, because the capacitance is low. It has so high input impedance that often I don't even have to touch the head to the circuit, it pick up the signal even from a few mm distance! You can find good deals about FET probes and good analog scopes (like Tek 485, Tek 2465, or HP 172x) on E-bay if you are serious about these. If you look for a FET probe always make sure the dividers are included, because if you miss them it is basically impossible to find a spare...
I bought the HP 1720A scope with the Tek probes locally for about 140USD, the HP FET probe was another 85USD... I briefly had a Yokogawa DL1740 4x500MHz scope as well, but it wasn't suiting well for CRT measurements despite its awesome bandwidth, I bought it for 280USD as faulty, repaired and then I sold it for 680USD, I regret it only a little
Honestly I don’t know… It is a nice scope except for one thing, it has very little memory, only 4kpts, so at slower timebases you can’t exploit the full sampling speed of the ADCs. As I see you have a modern digital scope already that is perfect for general measurements. In this case I’d recommend the Tektronix 2465 series to get while keeping the current scope as well, it is an analog scope with digital readout, the base model is 300MHz, but Tektronix was very generous with these specifications, there are several reports that they far outperform their advertised bandwidth, not to mention the later models (2465A: 350MHz, 2465B: 400MHz). There are loads of threads how to keep those scopes running flawlessly, so there are a lot of experts as well.
I went with the HP 1720 because this was the only one I could afford (and was available) at that time, this is a 275MHz scope and I’m sure it is indeed not more not even by a slight. Mine is already 40 years old and while it still holds up certainly show some sign of its age. The same vintage would be the Tek 485, which has 250MHz bandwidth in 1M Ohm input mode, but is 350MHz in 50 Ohm mode, but as I pointed out the 1MOhm input really does not matter much, (FET probes are working at 50 Ohm). I hacked my HP scope so at channel A I replaced the 50 Ohm termination resistors to 75 OHM, so I can directly connect video coax to it, using low impedance probing is an other way to go for high frequency measurements, but it is obviously not letting you to take real in-circuit measurements.
Later the day I might be able to post some pictures how the different probing techniques matters on the same signal/circuit.
So here are some measurement results. Rise time out of my pulse generator into the scope's input measures ~1.5ns, this is essentially the same with the HP 1120A FET probe, Testec 250MHz 10:1 probe about 1.8ns (but see later), Tek P6106 about 2ns or little more.
2ns/div uipper trace source directly to scope input 50 Ohm terminated, lower trace HP 1120A FET probe sniffing with a BNC Tee connector on scope's input, note the signal delay.
Same as above 10ns/div
upper trace the source (50 Ohm fully terimnated), lower trace Testec 250MHz 10:1 passive probe with the shortest ground possible, 20ns/div, note the ugly overshoot, this however can be adjusted on the probe but it seriously affects rise time.
Upper trace source (50 Ohm fully terminated), lower trace Tek P6106 250MHz 10:1 probe with typical 5cm ground clip, note the ringing which affects the source signal as well (hard to see on the picture). 20ns/div
The same as above (Tek 6106) but with the shortest possible ground connection.
These are the most ideal conditions. Also note that one pixel at 1080P 60Hz is 6.7ns wide...
zjjxhzf: hello Gabor i am DLP projectorColor wheel is not accurate，setup memory， the phase angle cant setting for the color wheel ，must use service code.
Sept 19, 2017 1:31:25 GMT -5
mastertech: Hi stranger. Guess you spent your summer cruising on that street bike.
Sept 17, 2017 21:43:54 GMT -5
nashou: Hey everyone, just saying hi ! Hvent been here for a while hope you're all doing well !!
Sept 17, 2017 19:19:25 GMT -5
mastertech: Parts for repair are no longer available.
Sept 11, 2017 19:42:24 GMT -5
mayavi: my pioneer elite VSX-92TXH it freezes until I unplug and then it won't power on until maybe 10 minutes. came to know that its a common problem in this model. any help would be much appreciated......
Sept 11, 2017 13:39:10 GMT -5
jaredjaric: Thanks so much Hulio :), your expertise is very much respected
Aug 20, 2017 9:25:37 GMT -5
Admin: james: you need to post in the thread where your problem is being discussed.
Aug 9, 2017 19:51:54 GMT -5
james: Yes Sir All wiring was connected.
Aug 9, 2017 7:46:15 GMT -5
Admin: I have uploaded a copy of the SM to the digital projector section.
Jan 10, 2017 20:21:56 GMT -5
ducki: sorrry for my bad english ....(google translate
Jan 10, 2017 17:44:21 GMT -5
ducki: I have the same defect as a cp-x4021n you but can not start it ... I did the same trials with ic202 pc102 and still do not like, I make short pin 1 and 2 of the pc102 and PJ light (orange) goes off ... you can help me with a service manual for this PJ? TNX
Jan 10, 2017 17:43:46 GMT -5
jlb12: pwr switch off = 2(0.0) 3(11.7) 6(.04) 7(.04)
Dec 13, 2016 23:27:03 GMT -5
jlb12: No Problem. Thank you for all your help.
Dec 13, 2016 0:20:40 GMT -5