26th May 2022, 9:31 am | #161 | |
Nonode
Join Date: May 2004
Location: Halifax, West Yorkshire, UK.
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Re: Perth PET
Quote:
Alan |
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26th May 2022, 12:27 pm | #162 | |
Octode
Join Date: May 2012
Location: Perth, Scotland
Posts: 1,762
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Re: Perth PET
The official documentation for this scope is (to put it politely) sparse.
OpenHantek has better docs - here: https://github.com/OpenHantek/OpenHa...ser_Manual.pdf But I can find no mention in there of any external triggers. There is a port on the device marked USBXI but Goggle isn't helping me much with that, nor is it mentioned in any of the documents. Colin. Quote:
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26th May 2022, 12:42 pm | #163 |
Nonode
Join Date: May 2004
Location: Halifax, West Yorkshire, UK.
Posts: 2,583
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Re: Perth PET
I think USBXI provides a means of networking devices so won't help much in this instance. As far as I know the Hantek has two channels but no external trigger facility.
Alan |
26th May 2022, 3:53 pm | #164 |
Octode
Join Date: May 2012
Location: Perth, Scotland
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Re: Perth PET
Dammit. UE9 replaced and no change.
Colin. |
26th May 2022, 4:16 pm | #165 |
Nonode
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Location: Halifax, West Yorkshire, UK.
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Re: Perth PET
Never mind, it was worth a shot and at least narrows down the possibilities. Will make future fault finding easier too.
Alan |
26th May 2022, 5:30 pm | #166 |
Dekatron
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
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Re: Perth PET
I think we are going to have to look more closely at the data bus but before we do let's just check that the address lines are going all the way to the PROM pins. We have only followed them to the outputs of the UE9 / UE10 buffers so far.
Reinstall the original PROMs and refit the NOP rig. Scope the following PROM pins, check that the frequencies on them are as given below and also check that all of the waveforms going to these pins are clean and full height. Code:
on UD6, UD7, UD8, UD9, pin 8, 250Khz on UD6, UD7, UD8, UD9, pin 7, 125Khz on UD6, UD7, UD8, UD9, pin 6, 62.5Khz on UD6, UD7, UD8, UD9, pin 5, 31.25Khz on UD6, UD7, UD8, UD9, pin 4, 15.63Khz on UD6, UD7, UD8, UD9, pin 3, 7.813Khz on UD6, UD7, UD8, UD9, pin 2, 3.096Khz on UD6, UD7, UD8, UD9, pin 1, 1.953Khz on UD6, UD7, UD8, UD9, pin 23, 976.6Hz on UD6, UD7, UD8, UD9, pin 22, 488.3Hz on UD6, UD7, UD8, UD9, pin 19, 244.3Hz on UD6, UD7, UD8, UD9, pin 18, 122.1Hz Code:
CPU pin UD9 pin 33 9 32 10 31 11 30 13 * note UD9 pin 12 is skipped 29 14 28 15 27 16 26 17 |
26th May 2022, 6:00 pm | #167 |
Octode
Join Date: May 2012
Location: Perth, Scotland
Posts: 1,762
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Re: Perth PET
Continuity first - all checks out. Would a resistance reading be useful?
Colin. |
26th May 2022, 6:39 pm | #168 |
Dekatron
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
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Re: Perth PET
Not generally, as 'continuity' implies very low or no resistance. If the resistances are <2 ohms including the resistance of your meter leads, that would be a pass. Anything higher would be 'a measurement of interest'
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26th May 2022, 6:49 pm | #169 |
Nonode
Join Date: May 2004
Location: Halifax, West Yorkshire, UK.
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Re: Perth PET
I must admit that I rarely use a meter's continuity feature for this sort of thing, preferring to measure the actual resistance. As long as the reading is less than a couple of Ohms everything should be fine allowing for lead and contact resistance. Posts crossed.
Alan |
26th May 2022, 6:54 pm | #170 |
Dekatron
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
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Re: Perth PET
True, there are pros and cons for using the 'continuity' feature of a meter depending on whether it is stand-alone or combined with something else.
Continuity on a switch position on its own usually indicates the resistance anyway and buzzes as long as the resistance is below a certain ohms figure but that threshold can be quite high, so I always look at the reading in addition to listening for the buzz. |
26th May 2022, 6:56 pm | #171 |
Octode
Join Date: May 2012
Location: Perth, Scotland
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Re: Perth PET
All less than 2 ohms so that seems to be ok.
This flippin NOP device falls apart every time I look at it. You'll have to wait a little while I'm afraid. |
26th May 2022, 7:00 pm | #172 |
Nonode
Join Date: May 2004
Location: Halifax, West Yorkshire, UK.
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Re: Perth PET
My first meter (analogue then of course) didn't have a continuity/diode function so I've never bothered with such things since!
Alan |
26th May 2022, 7:04 pm | #173 |
Dekatron
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Location: Newcastle, Tyne and Wear, UK.
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Re: Perth PET
OK - if you are reworking it anyway, the power pickup leads you currently have going from the NOP rig to UG4 pads - your life might be easier if you took those to the NOP rig's CPU socket pin 8 (for +5V) and the NOP rig's CPU socket pin 1 (for 0V). That would make it easier to insert or completely remove the NOP rig.
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26th May 2022, 7:35 pm | #174 |
Dekatron
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
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Re: Perth PET
Have to disappear for the evening, sorry - SWMBO has a technical emergency which requires my assistance - 70 miles away!
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26th May 2022, 9:51 pm | #175 |
Octode
Join Date: May 2012
Location: Perth, Scotland
Posts: 1,762
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Re: Perth PET
That's OK. I'll try to get some kind of report back later on.
Don't ever ask for a photo of my NOP device. Even I'm embarrassed. And it's my birthday tomorrow so don't expect anything too coherent tomorrow. Colin. |
26th May 2022, 10:25 pm | #176 |
Octode
Join Date: May 2012
Location: Perth, Scotland
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Re: Perth PET
OK - all ROMs are showing the frequencies as above on all pins.
Couple of questions: 1) what voltage should the pins be showing when powered on with the NOP device fitted? 2) Pin 12 on UD9 does not connect to earth as the schematics say it should (page 4) but to a capacitor - C9; is there a reason that the schematics don't show this? Colin. |
26th May 2022, 10:51 pm | #177 |
Octode
Join Date: Mar 2020
Location: Kitchener, Ontario, Canada
Posts: 1,264
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Re: Perth PET
Pin 12 on UD9 should be connected to ground. The capacitor is probably a decoupling capacitor connected between ground and 5v.
Check continuity between Pin 12 on UD9 and pin 12 on the other proms, or some other known 0v ground. |
26th May 2022, 10:59 pm | #178 |
Nonode
Join Date: May 2004
Location: Halifax, West Yorkshire, UK.
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Re: Perth PET
IC decoupling capacitors are quite often omitted from complex schematics. Their presence is just assumed. I think you'll find that there is continuity between Pin 12 and earth even though you can't see the connection to the PCB ground plane. Have a good day tomorrow Colin!
Alan |
26th May 2022, 11:10 pm | #179 |
Octode
Join Date: May 2012
Location: Perth, Scotland
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Re: Perth PET
This is what's confusing me. I get continuity to the one of the capacitor legs, but not to either ground or any of the other pin 12s.
Colin. |
26th May 2022, 11:24 pm | #180 |
Octode
Join Date: Mar 2020
Location: Kitchener, Ontario, Canada
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Re: Perth PET
Then you might have found a fault. Add a wire link from the capacitor pin that connects to UD9 pin 12 and pin 12 of one of the other proms.
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