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Old 22nd Feb 2021, 4:52 pm   #21
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Default Re: Philips N1500 - can it be tricked?

af024, thanks for your message. I will try altering the belt position as youíve described and get back with the result.
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I've found that these machines were not brilliant at synching up material recorded by other machines. Have you tried to record something on your machine and playing that back?
Havenít tried making a test recording on this machine yet, but will do so when itís certain I wonít be recording over any old footage.
The picture disturbance is exactly the same as Iíve experienced sometimes on old Beta tapes whilst playing in a Sanyo VTC5150, which was cured by altering specific variable resistors on that machineís servo board just for those tapes, and can see that there are also variable resistors on the the servo board in the N1500. If only it were that simple!

Philip
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Old 24th Feb 2021, 12:02 am   #22
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Default Re: Philips N1500 - can it be tricked?

HurtyAC, still to try with the capstan eddy brake disconnected.

af024, tried your suggestion with the belt position but no change.

The adventure continues...

Philip
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Old 24th Feb 2021, 8:16 am   #23
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Default Re: Philips N1500 - can it be tricked?

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Finally, an update. Loading mechanism repaired, new drive belts fitted,
>>
>>

Philip
Hello,

I've also got an old model N1500/15, I picked-up many years ago, that I need to get round to fixing - I found a metal loading drive gear's teeth were stripped a bit, after spending 2 nights removing all the goo the rubber belts had gone to. So looks like having to try and re-make something, assuming nowhere has spares any more.

So I was just wondering if you'd found a supplier for recently-made new replacements for yours or if you were using NOS ones (which I presume most of these would have suffered badly with age by now)?
I think I did look through my old belt kits, but hadn't got anything of about the right sizes
But I think I did manage to get an original of the service manual, in case it's not all online somewhere.

TIA,
Owen
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Old 24th Feb 2021, 8:47 am   #24
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Default Re: Philips N1500 - can it be tricked?

Owen, there are plastic gears associated with the tape loading system (plus the cord and pulley), all of these to the right of the head drum. If that’s what you mean, 3D-printed replacements (plus belt kits) are available from a Dutch supplier on a well known auction site. It was NOS gear parts I used which are doing their job well, so far.

If your restoration does not go forward, please let me know if the machine becomes available.

Philip
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Old 24th Feb 2021, 11:08 am   #25
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Default Re: Philips N1500 - can it be tricked?

So you positioned the belt on the motor pulley to essentially increase the diameter at the motor pulley location, thereby increasing the capstan shaft speed and that didn't help.
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Old 24th Feb 2021, 11:27 am   #26
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Default Re: Philips N1500 - can it be tricked?

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Owen, there are plastic gears associated with the tape loading system (plus the cord and pulley), all of these to the right of the head drum. If that’s what you mean, 3D-printed replacements (plus belt kits) are available from a Dutch supplier on a well known auction site. It was NOS gear parts I used which are doing their job well, so far.

If your restoration does not go forward, please let me know if the machine becomes available.

Philip
Thanks for reply with useful info - I've just found your post from 2016 about the supplier in Holland

I had wondered about trying to 3D print something, if it couldn't easily be machined. I've just taken a look again at it, and it seems I took out this 'Toothed wheel' gear (Chassis Part No. 193 in Service Manual, part no. 4822-505-10029) I'm sure was metal, but have temporarily misplaced.
It fits at the top of the shaft from the Threading In/Out motor, with a grub-screw to retain it - just above the threading cord pulley - drive a couple of plastic gears / cam to activate 2 'mode' switches.


It would be nice to get it going one day, as also have tapes - Especially as back in 2007 someone was trying to sell one at £400 that said it was working but just needed replacement belts (which led you to wonder how they tested it / if belts had been available (N1700 NOS 4 belt set were being sold for £50, but not sure if any of these were same as the 3 in the N1500).

I was also given a couple of N1700's, after the owner bought another online to copy his old tapes as I think the heads had worn on these - And replacements were NLA / v.expensive when they were.
But these may have had Television magazine mods for longer tape time.

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Old 24th Feb 2021, 1:23 pm   #27
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Default Re: Philips N1500 - can it be tricked?

Regarding the capstan-speed / servo-lock issue, it may be worth having a look through this (recent post?) - in case you haven't already discovered it:

https://www.radios-tv.co.uk/communit...age-artifacts/


Which I found at the bottom of this posting (where they'd also had belts turn to a gooey mess): https://www.radios-tv.co.uk/communit...n1500-finally/

- This has quite a few good photos of the insides / the special 'jig stand'
Plus it also mentions the Combiined Electronic Services (ces) = Philips / Pye Service Link publication, which may be available on their to members
(I've got 3 copies from 1974, which includes info & mods etc. on the N1500, so had been trying to find if any others were available on the 'net)

I found I actually picked up 2 copies of the service manual over the years, and both seem to have several addendum inserts (in different places, but same contents?) with details of manuals corrections / changes & production changes.
- Of which some of the first seem to be a revised version of the infamous loading pulley plus they also changed the motor for a slower more powerful one to reduce noise and also had a flat on the side of spindle at the top to sort problems with the gear slipping.
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Old 24th Feb 2021, 3:00 pm   #28
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Default Re: Philips N1500 - can it be tricked?

af024, the belt was taken out of the groove as you suggested but made no difference.

However, since then, have come across two pages from Television dated December 1977 which details the cure for this exact picture issue: to first check R276 and D209 [on panel 23 which is to do with playback servo, as Iíve suspected all along]. On this machine R276 is reading 3.6 ohms instead of 2.7, and D209 has shorted, so until I can get the board removed from the chassis to check all other components, will assume there are likely to be more that need replaced.

Getting there now, but my soldering skills are terrible so may take a while!

Philip
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Old 24th Feb 2021, 3:48 pm   #29
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Default Re: Philips N1500 - can it be tricked?

Owen, that first link you included is the exact one I discovered in the early hours of this morning and have since been able to at least trace a fault, if not all of them.

The part youíve misplaced is the one in the attachment, yes? If so, this is one of two spares I have (but no spare grub screw), so if you get to the point of obtaining the other parts from Holland, let me know and I can send you this part. Also have some Service Link brochures, and the intention is to scan these and make them available on here when time allows.

The Service Manual information sheets with changes / corrections sometimes state from which chassis number they apply, so you can narrow down what is relevant to yours.

Always on the lookout for a spare N1702 for parts as well, so if either of yours are that model and may become available, please let me know.

If neither of us get our N1500 operational, video99.co.uk does transfers of this format videotape.

Philip
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Old 24th Feb 2021, 8:54 pm   #30
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Default Re: Philips N1500 - can it be tricked?

af024, please disregard most of what’s in post #28, I don’t even know if R’s and D’s can be tested in circuit. Even if they can, having difficulty understanding multimeter readings on diode check setting, AFTER reading up on this online!
Maybe a working N15xx will appear one day.
Thanks for everybody’s help posts.

Philip
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Old 28th Feb 2021, 12:06 pm   #31
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Default Re: Philips N1500 - can it be tricked?

Thanks for the info on your previous post / picture of the 'missing' part.

A photo of the part is rather better than rough drawings in the manual, and I've just checked again and found it is still in fact in my machine!

It was just that the metal teeth are such a fine pitch compared to the plastic gear it engages with, that I'd assumed that they'd worn down a lot as seem to recall they weren't engaging / had got damaged from the mechanism being forced. But it was a long time ago now, so will have to remount the gear assembly, and take a look again to see what's going on.

Yes, I might also scan my copies of Service link and upload somewhere, if these don't seem to exist anywhere (there seemed to be mention of ones available to members on that www.radios-tv.co.uk webpage). Although my HP all-in-one's scanner is extremely-slow, so I need to have a play with some others I have.

BTW, you should be able to test that resistor / diode in-circuit, providing they aren't in parallel with a very low resistance. And the increase in resistance, from 2.7 to 3.6R maybe due to the resistance of your test-leads , so need to subtract the reading you get when joining them togther (unless you've got a DMM that support 4-terminal kelvin leads, that takes this out or a null option to automatically subtract any resistance)
Diode-check should just around 0.6V with leads one way and '1' (over-range) the other way, unless there's a low-resistance across it in the circuit, that causes a mis-reading.
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Old 28th Feb 2021, 2:04 pm   #32
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Default Re: Philips N1500 - can it be tricked?

Owen, the fine teeth on the metal part in the photo are for sliding another plastic gear on to, which is a common failure. That plastic gear is one of the parts available as the 3D-printed replacement.

The resistance of the DMM test leads is negligible but will desolder suspect parts to double check. The diode in doubt is showing 0.4V in both directions so assuming short-circuited, but again, will now remove to double check.

Many thanks.

Philip
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Old 4th Mar 2021, 10:41 am   #33
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Default Re: Philips N1500 - can it be tricked?

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Owen, the fine teeth on the metal part in the photo are for sliding another plastic gear on to, which is a common failure. That plastic gear is one of the parts available as the 3D-printed replacement.

Philip
Thanks for the info. I don't recall removing anything from this - it may have broken-off, but quite a while ago now.
And it would have been nice if the manual had some better drawings / photos, that later VCR service manuals often had. So I will keep an eye out for any more recent photos that anyone's taken and maybe posted online.
Plus I'll investigate getting a 3D-printed replacement if I can find it on a translated version of that website, so thanks for that info.

Owen
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Old 11th Mar 2021, 4:19 pm   #34
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Default Re: Philips N1500 - can it be tricked?

Owen, these two photos may help, showing you the plastic gear required and where it slides on to.

Philip
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Old 11th Mar 2021, 4:34 pm   #35
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Default Re: Philips N1500 - can it be tricked?

Whilst awaiting the arrival of an oscilloscope, have been comparing the audio/sync head in the machine with a NOS one which have not yet opened, and am wondering if the existing unit is worn/damaged [see photos]. Current audio reproduced is fine, itís still the picture synchronisation (methinks) thatís an issue, updated video at:

https://youtu.be/Nmxu40wXl40

Philip
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Old 12th Mar 2021, 5:24 pm   #36
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Default Re: Philips N1500 - can it be tricked?

I've had something similar Philip. I couldn't adjust the problem out. It was a case of either reasonable audio or reasonable syncs. Getting both was tough going. Again I get the impression that material wasn't very transportable from one machine to another, so things must always have been a bit hit and miss. I remember watching whole programmes at school with the issue you have recorded for us! I don't have the schematics to hand, but there must be somewhere to monitor the pulses. It would be good to see what they look like and what level they are at compared with a working machine/tape. Have you managed to record anything on your machine yet?
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Old 12th Mar 2021, 11:51 pm   #37
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Default Re: Philips N1500 - can it be tricked?

af024, I did try making a recording using the RF output from a Sanyo Beta (donít have any other device that outputs RF) but playback resulted in no picture or audio. The lamp for the colour signal did light up though when receiving the Beta output!
I do have the Service Manual, and the arrival of an oscilloscope is imminent, so will try and confirm whether or not correct waveforms are produced in the playback servo section.
In the meantime, the brake disc for the flywheel has been slightly adjusted as it was slightly too high, but there is still so much vertical play in that shaft which is integral with the capstan motor that am wondering if this is not allowing the eddy brake to function properly...
The frustration is subsiding, as this may need expert attention.
If you need any Service Manual scans, let me know.

Philip
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Old 13th Mar 2021, 9:37 am   #38
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Default Re: Philips N1500 - can it be tricked?

Hello Philip, yes, from memory, mine also has loads of vertical play. I guess that's how they are. I don't think that the position s that critical so long as it's all free to rotate without catching somewhere.

Fingers crossed that the scope will help. I can.t remember whether the service info provides any typical waveforms. Let's hope …

Strange about the RF signal. I wonder if it just wasn't tuned in? Can you monitor the N1500s RF output whilst trying to tune in one if its tuner buttons to the Beta's output? Are the slider switches engaged with the piano keys?

Extracts from the service info will no doubt help at some point.

Keep going. I mean you seem to have good video heads and there's a load that is working ok. Shame to give up.
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Old 13th Mar 2021, 9:43 pm   #39
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Default Re: Philips N1500 - can it be tricked?

af024, thatís good to know that the play in the shaft seems acceptable, and the brake disc is definitely in the middle of the air gap when the machine is horizontal.
The Service Manual does show numerous waveform images for circuit diagrams A through E, so they will undoubtedly be very useful.
The procedure I used for tuning in was as described in the opening couple of pages in the Service Manual, which was to start the tape in recording mode, tune in an external signal, and although the signal level indicator did not seem to function (itís illumination lamp did), the RF output was already connected to TV so I could see the e-e (correct terminology?) output on the screen which was strong, and the colour signal lamp indicator was bright.
Weíre getting there...!

Philip
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Old 15th Mar 2021, 11:16 am   #40
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Default Re: Philips N1500 - can it be tricked?

I didn't know that they provided a procedure to tune in, well you live and learn. I just put mine on fast forward (or was that rewind I forget now) with no tape in to keep the machine turned on and went from there.

Yes I had a feeling that some waveforms were provided in the service info so hopefully they will be useful as you say.

Keep going now, we want to see this thing running properly.
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