So after a short break, let's prepare for round two. This time I will use big boys toy's as well, as I arranged a good deal on a 500MHz active FET probe (HP 1120A), I believe this will make a good pair with my HP 1720A oscilloscope, and will let me take accurate measurements on the HF performance of each stage.
Unfortunately it turned out that the probe had a defective DC restoration circuit (not important for these measurements, but why not fix a broken circuit? ) also the divider which came with the probe didn't work well, so I had to look for new dividers, then I had to spend some time to find out how to compensate the new dividers to the probe. And since these were as-is items I had to check if they are really up to their specs (roughly at least).
And finally had to find some spare time to play with the circuits.
Originally I wanted to test a PG xtra neckboard as well, but I wasn't able to feed the board with the appropriate input signal (4Vpp signal on 3VDC). So jumped to the XG boards again, with the FET probe it again became obvious that the sony preamp IC isn't that good as the spec. sheet says, (they claim 2ns rise time with 4Vpp output) while I only measured only 3,5ns at 2Vpp (~100MHz). The discrete preamplifier board seems to be quite good as it doesn't really affect signal speed, and now I measured nice shaped signals throughout to the input pins of the videopacks. The output of the videopack is still poor in speed, though no odd distortions as earlier, about 12ns rise time, which means 30MHz BW. This seems to be believable based on what I can see on the screen. Of course the question still remained: Why this low? But this time at least the measuring equipment can be ruled out from the faking factors. More to come...
So, I managed to get the PG xtra neckboard working, figured out that I can use the preamplifier on the XG neckboard to drive the PGx's, the VPA13 on that board performed considerably better, measued 4ns rise time at 55Vpp output, and since the input wasn't much faster than that this is a very good result. I have to conclude that the problem must lie in the XG's board (material) then, since I already swapped the output ICs multiple times, bypassed all possible components that can load the output of the IC, and the VPA13 can perform much better on the other board even with the preamplied signal from the XG board. This also means there isn't really anything I can do to make them better now.
What do you think MT, am I missed something should I check anything else?
An ic's performance (or any component or circuit) is only as good as the juice that runs it.
Yes, for these tests I built a simple powersupply with the needed voltage for the neckboards, so they are different from the machine's supply. Plus when I tested the PG xtra board tied to the XG board I used the same power supply, the PG xtra was good, the XG board wass bad, the supply was the same.
Great! How does the spotkill and I sense signal go to the Nec? Is that compatible?
The spot kill seems to be compatible, I sense isn't looking hard either, the biggest problem is that there is a gain (contrast) trim pin on the XG neckboards, that is not present in the VNB, and I really don't want to poke with analog multipliers in this project.
Actually he already helped me so much that I feel shame to ask more... To say the least I got this power supply absolutely free, he not even let me to cover the shipping costs...
I invited him. He's going to drop by and have a look see. How are the CRT pin outs on the Marquee vs the NEC tube? Which NEC tube are you going to try on?
Currently I have no NEC spare tube, so I have to make absolutely sure on the bench the spotkill works as it should before putting in the machine... Not the pinout is the biggest problem with the E'home vs. NEC but the tube socket, the NEC tubes use the thin-neck tube, therefore narrower CRT socket, I already have a few ideas to overcome this, will turn out which one works best
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