Well I'm either blind, stupid or both. I cannot find a 30-pin Z2 anywhere. So I thought no problem just pick up the voltage from N13-5, nope cannot find that either. OK so R91 then, nope. Aghhhhhh! I've looked through the manual and unfortunately there's not 'Thicko' board locator showing where it is.
I can see on page 99 the plan view of the PCB with all the points I need but physically I cannot see it. I'm suspecting its topside under the right hand side but to gain access would mean removing all manner of things to get to it, two of which state under no circumstances remove these screws! What an absolute mare of a job, surely they must have known what a problem that would present for servicing, why not just make that right-hand side part of the top removable, beggars belief.
If I smoked I'd go and have one so a coffee will have to do! ?
Indeed that is where the CONT board is and the 30-pin Z2, N13 and others.
A total mare to get at with multiple screws to remove, front fascia control panel, spindle platter etc even with the cover off there was another shield covering the CONT board. Then removing that shield reveals yet another soldered to both sides of the board, no getting directly onto the pin.
I will have to get in via the N13-5 track or R91 to get my scope to read. No way to have a disc loaded and I can only assume its OK to power up in this dismantled state. I will somehow have to defeat the open lid interlock as it won't do anything with that removed, probably easiest to just rest the lid back in place and let the lock latch. Compared to the VLP600 access to service this pioneer is hideous, way less friendly than the Philips and all this to find out a voltage for FOCUS lock. ?
That is absolute madness, and how on earth do you set up the three pots I can see!
I know John, its absolutely ridiculous, no thought given towards the service tech, guess I've been spoilt by Thorn. As I mentioned above the Philips VLP600 shows how to make a player serviceable, the Pioneer, how not to!
Anyway I soldered on a wire to the underside of the CONT board to pin N13-5, hooked up the scope and took the following readings.
The player was off, I powered on, defeated the interlock, pressed play, as usual it failed to focus (well it would as there isn't a disc in but take my word for it the fault is present) so it dropped into the four retry sequence before finally reject. I repeated pressing play three further times (that makes for, four goes) before finally releasing the interlock and then powering off.
I scoped the entire operations and they are shown and annotated below.
Just to be absolutely clear the laser lens can be seen moving up and down when the waveform is at zero volts? This is what I would expect but doesn't explain why you are seeing 3.4V at N7-5 on the VSOP, there's only really a 220ohm resistor between there and pin 30 of Z2 on the CONT. Have you checked for FOCUS LOCK going low at all? its at N7-6 or N13-1 and will obviously need to be carried out with a disc present.
Just to be absolutely clear the laser lens can be seen moving up and down when the waveform is at zero volts?
no, its bopping up and down when its at 4.4V as indicated on the above oscillogram (x4 retry=objective lens bopping), at the end of the fourth attempt, it enters reject mode and then drops back to 0V.
Ok, that is the way I read it from your waveform but I doubted my own interpretation as it being active low it seems to me to be the reverse of what it should be. I would have expected the laser to attempt to focus only when low, now if only you had a worker to compare ?
Hope this adds some flesh to the problem rather than just text and photos.
Another thing that's troubling me is the focus error S-curve waveform does not appear to be present when play is pressed when monitoring TP1. All I have is -12.3V. Also Z3 pin 7 is at -12V and does not change when PLAY is pressed.
It would be a good idea to switch off the autoranging on your Fluke and manually select 20v but to be honest scoping on DC would be the best way to do it, meters are just not fast acting enough with digital stuff. I'm baffled why on the yellow meter there is no volts or change at N7-5 which is directly connected to N13-5 and then on to Z2 pin30 via R91 which you scoped yesterday, also there is no way the spindle motor is going to rotate until F.LOCK goes low and stays low. As for the -12V at Z3 pin 7 I don't think it's relevant yet, I would be more interested in the voltages on Z1 and to see what you have at the slider of VR1 the focus offset pot.
BTW just watched the video again and are you aware the yellow meter connected to N7-5 is set to I think 200mV? Something very wrong here.
I connected up the scopes, they pretty much confirm what the meters were reporting
So is N7-5 showing 4V on the Owon and 0V is at the bottom of graticule and on the mono TEK?
- Colour TEK shows 4.9V on N9-2 This is what the Metrix meter was reading in the video.
- Mono TEK 1st photo shows N7-6 120mV p-p when player just powered on. This is what the Fluke was reading in the video
- Mono TEK 2nd photo shows N7-6 4.5V p-p when play is pressed and focus lock sequence active. This is what the Fluke was reading in the video.
- OWON shows N7-5 160mV p-p constant no change. This is what the yellow meter was reading in the video though not very well (its a naff old meter and needs replacing).
Sorry Chris but when showing DC voltages on a scope we need to know where 0v is to get a meaningful reading, I usually set the Y shift so that it's at the bottom with the tip grounded.
You definitely need to find out whats going on with N7-5 to N13-5 connection and then on to pin 30 on Z2. I'm wondering if there is a mistake in the manual as your previous check shows change at Z2 even though to me it's opposite to what it should be.
Sorry Chris but when showing DC voltages on a scope we need to know where 0v is to get a meaningful reading
I normally set zero on the centre of the graticule so as to easily see +ve or -ve ( as indicated on a previous post as shown below)
Ok I'll remember that for the future ?
Sorry for not stating on the photo examples, my bad!
I'm must admit I'm really struggling with this one, the manual and circuit I'm finding tough going, its way ahead of what I've encountered thus far, should probably stick to telly's. I think that's it for today, I'll come back to it tomorrow and investigate the areas you suggest ?
An article from 1978, not technical but thought you may like to read it.
https://www.americanradiohistory.com/Archive-Modern-Electronics/Modern-Electronics-1978-02.pdf
Hi Guys an update as to where I'm at.
Having invested in new piece of test equipment namely the scope/logic analyser (for info on that unit see here), I'm trying to get to grips with hooking in the MSO. In particular getting the logic analyser side of things into the LD1100 and I suspect I'm going about it all wrong due to my unfamiliarity with LA's. I thought I would start by connecting the logic analyser to the three test points mentioned above, these being the initial start-up sequence :-
- VSOP N7-6 focus lock signal
- VSOP N7-5 focus run signal
- VSOP N9-2 spindle run signal
Note: spindle run and focus lock should be 'LOW'
I set the LA to display only eight of the 16 channels as it was a menu option, I later discovered in a sub menu you can trim this down further to display just the ones your testing, which in my case is D0 =spindle run, D1=focus lock and D2=focus run. With the LA connected and the laser player powered off, you can see the result below.
I then powered the laser player on, D0 and D1 registered a change in height on the display as indicated by the arrows D2 remained static. This correlates to the prior testing where the focus attempts its sequence before fall-back to reject as it never gets to focus, therefore D2 signal is not present.
I power cycled and pressed play observing the behaviour and it was consistent, however one brief time and sadly not repeatable, the spindle run and I think the focus lock traces showed a signal. This appeared ever so briefly and showed as three or four steps on the D0/D1 lines. As I say, I've tried it numerous times since to get it to do that again so I can hit run stop to capture and investigate but its not happened again.
I've manually drawn what I briefly saw in pink on the example below.
As I state above, I'm not sure I'm driving the LA side of this new scope correctly. I just need to keep plugging away and searching for info on the web to see if I'm setting this all up correctly. Anyway that's where I am with this player and I will update as and when I hopefully make some progress worth reporting.
As stated and suspected above, its me badly driving the MSO. I found the correct trigger option and now I can get the High/Low captures. Still figuring out as I go, bet you're glad I'm not a 747 pilot. ?
And adjusting the time from milliseconds to nanoseconds gives me a wider view of the activity. Not only can I see the D0 and D1 signals but now I can see there is in fact a signal appearing on D2 for FOCUS RUN.
What is apparently confirmed by these captures and my previous dmm readings, the pins of N9-2 and N7-6 are in the incorrect state, that being HIGH rather than LOW.
Having its state confirmed is good, knowing it is one thing, ascertaining why is another ball game so I'm not sure I'm any further on at this point.
